ArticlePDF Available

High adsorptive potential of calcined magnetic biochar derived from banana peels for Cu 2+ , Hg 2+ , and Zn 2+ ions removal in single and ternary systems

Article

High adsorptive potential of calcined magnetic biochar derived from banana peels for Cu 2+ , Hg 2+ , and Zn 2+ ions removal in single and ternary systems

Abstract and Figures

The use of banana peel as a sustainable and low-cost precursor for the fabrication of effective biochar was exploited. Here, calcined magnetic biochar (CMB) was fabricated and characterized. CMB possesses surface acidic functional groups (-OH and COO −), porous structures, high saturation magnetization (39.55 emu/g), and larger surface area than the non-magnetic biochar (CB). The CMB adsorption performance (72.8, 75.9, and 83.4 mg/g for Zn 2+ , Cu 2+ , and Hg 2+ , respectively at pH 6) in a single component was described suitably by pseudo-second order kinetic model, Langmuir, and Redlich-Peterson adsorption isotherms. Notably, the selectivity factor values in the extended Langmuir isotherm indicated that CMB has higher adsorption affinity toward Hg 2+ than Cu 2+ and Zn 2+ in the multi-component system. Owing to its high adsorption efficiency and fast and easy separation, the calcined magnetic biochar is considered promising and effective for the purification of heavy metal-bearing wastewater.
Content may be subject to copyright.
RESEARCH ARTICLE
High adsorptive potential of calcined magnetic biochar derived
from banana peels for Cu
2+
,Hg
2+
,andZn
2+
ions removal in single
and ternary systems
Akeem Adeyemi Oladipo
1,2
&Edith Odinaka Ahaka
2
&Mustafa Gazi
2
Received: 3 June 2019 /Accepted: 26 August 2019
#Springer-Verlag GmbH Germany, part of Springer Nature 2019
Abstract
The use of banana peel as a sustainable and low-cost precursor for the fabrication of effective biochar was exploited. Here,
calcined magnetic biochar (CMB) was fabricated and characterized. CMB possesses surface acidic functional groups (OH and
COO
), porous structures, high saturation magnetization (39.55 emu/g), and larger surface area than the non-magnetic biochar
(CB). The CMB adsorption performance (72.8, 75.9, and 83.4 mg/g for Zn
2+
,Cu
2+
,andHg
2+
, respectively at pH 6) in a single
component was described suitably bypseudo-second order kinetic model, Langmuir, and Redlich-Peterson adsorption isotherms.
Notably, the selectivity factor values in the extended Langmuir isotherm indicated that CMB has higher adsorption affinity
toward Hg
2+
than Cu
2+
and Zn
2+
in the multi-component system. Owing to its high adsorption efficiency and fast and easy
separation, the calcined magnetic biochar is considered promising and effective for the purification of heavy metalbearing
wastewater.
Keywords Banana peel .Magnetic biochar .Competitive ternary adsorption .Heavy metal .Kinetics
Introduction
The increasing water pollution by toxic heavy metals is
of heightened global interest and considered a serious
environmental threat. The continuous discharge of efflu-
ents from metal finishing, mining, smelting, steel, glass,
and battery manufacturing, is harmful to human health
and ecosystems. Unlike organic contaminants, the dis-
solved heavy metal ions have a high tendency toward
bioaccumulation because they do not degrade naturally,
thus resulting in detrimental health problems (Bouhamed
et al. 2016;Lietal.2019a,b; Mousavi et al. 2018).
Copper (Cu), zinc (Zn), and mercury (Hg) are widely
used and commonly detected in industrial wastewaters; in
excess concentrations, they can destroy the liver, kidney,
and nervous, gastrointestinal, and hematopoietic systems
(Cataldo et al. 2013; Godiya et al. 2019; Hasan and
Srivastava 2009;Lietal.2019a,b; Tauanov et al. 2018).
Accordingly, the World Health Organization (WHO),
Environmental Protection Agency (EPA), and the
European Union have regulated the maximum allowable
concentration of heavy metal ions in drinking water (EPA
1982; Tauanov et al. 2018;WHO2004). To comply with
the strict regulation, several purification methods have
been utilized (Fu and Wang 2011;Giwaetal.2019;
Oladipo 2018a,b,c; Yan et al. 2018).
For water contaminated with high concentrations of
heavy metal cations, chemical treatment, membrane bio-
reactors, reverse osmosis, and electrochemical treatment
are effectively used. Although, application of these re-
moval technologies has obvious drawbacks such as high
sludge generation and fouling and becomes expensive at
Responsible editor: Tito Roberto Cadaval Jr
Electronic supplementary material The online version of this article
(https://doi.org/10.1007/s11356-019-06321-5) contains supplementary
material, which is available to authorized users.
*Akeem Adeyemi Oladipo
akeemoladipo@csu.edu.tr; akeem.oladipo@gmail.com
1
Faculty of Engineering, Cyprus Science University, via Mersin 10,
Girne, TR North Cyprus, Turkey
2
Polymeric Materials Research Laboratory, Chemistry Department,
Faculty of Arts and Science, Eastern Mediterranean University, via
Mersin 10, Famagusta, TR North Cyprus, Turkey
Environmental Science and Pollution Research
https://doi.org/10.1007/s11356-019-06321-5
Fig. 4 Effect of solution pH on (a) copper adsorbed on CMB and CB (b,
c, and d) mercury, zinc, and copper adsorbed on CMB, respectively con-
sidering the metal ion speciation. Note that the bars are linked with the
removal (%) (experimental conditions: biochar dosage = 0.5 g, T=298K,
initial metal concentration = 200 mg/L, and contact time = 120 min. Error
bars indicate standard deviations for duplicate measurements).
Fig. 5 Effect of (a, b) adsorbent dosage onthe adsorption performance ofCMB and CB, respectively, and (c, d) initial metal concentration (experimental
conditions: initial pH = 6.0 ± 0.1, T= 298 K, and contact time = 120 min. Error bars indicate standard deviations for duplicate measurements)
Environ Sci Pollut Res
72.8, 75.9, and 83.4 mg/g for Zn
2+
,Cu
2+
,andHg
2+
,re-
spectively. Adsorption in ternary systems revealed that
Hg
2+
inhibited the adsorption of Cu
2+
significantly. The
results herein confirmed the potential application of
Table 3 Single- and multi-component isotherm parameters for metal ions removal
Isotherms Equations Parameters CMB CB
Cu
2+
Zn
2+
Hg
2+
Cu
2+
Zn
2+
Hg
2+
Freundlich logq
e
=logk
f
+nlog C
e
k
f
(mg/g)(mg/L)
n
12.9 12.6 13.5 11.8 11.5 10.6
n1.11 1.43 1.56 1.34 1.09 1.32
Δq
e
8.8 8.3 9.2 6.9 7.4 8.9
R
2
0.923 0.945 0.964 0.913 0.919 0.955
χ5.8 4.9 4.6 6.9 6.2 6.3
Langmuir C
e
/q
e
=1/q
m
b+C
e
/q
m
q
m
(mg/g) 75.9 72.8 83.4 44.9 53.9 45.5
b(L/mg) 11.5 9.1 12.9 8.2 7.5 10.3
Δq
e
2.9 2.2 1.1 3.4 5.3 2.9
R
2
0.976 0.989 0.999 0.999 0.989 0.994
χ1.2 1.8 3.1 1.9 3.4 2.3
Redlich-Peterson Ce=qe¼1=krp þCg
earp=krp k
rp
(L/g) 0.0782 0.0681 0.0599 0.0318 0.0399 0.0387
a
rp
(L/mg)
g
0.0034 0.0038 0.0041 0.0056 0.0062 0.0049
Δq
e
2.8 2.5 1.4 3.2 4.9 2.8
g1.11 0.99 1.01 0.98 1.12 0.96
R
2
0.993 0.998 0.999 0.988 0.995 0.996
χ1.11 4.42 3.38 23.19 14.42 6.40
Multi-component isotherm analysis for competitive metal ion adsorption by CMB
System Concentration (mg/L) Extended Langmuir isotherm parameters*
C
o,Cu
C
o,Zn
C
o,Hg
q
m
(mg/g) nβR
2
χ
Cu
2+
ternary 20 20 20 32.7 2.11 2.67 0.996 1.45
20 10 20 38.9 3.91 1.98 0.987 2.11
10 10 10 69.5 3.19 0.89 0.989 6.12
Zn
2+
ternary 10 10 10 19.6 2.87 1.67 0.999 4.89
20 20 20 29.9 1.89 2.09 0.997 5.44
10 20 10 45.8 3.89 2.87 1.000 9.11
Hg
2+
ternary 20 20 10 42.5 2.24 2.99 0.989 6.89
10 10 20 49.5 3.37 3.15 0.999 7.33
20 20 20 53.5 4.01 3.55 0.988 8.96
C
o
, initial metal ion concentration; CMB dosage, 0.05 mg; pH, 6; contact time, 360 min
*Extended Langmuir equation given in our recent reports (Oladipo et al. 2015; Oladipo and Gazi, 2015b)
Scheme 1 Illustration of the removal mechanism of heavy metal by calcined magnetic biochar
Environ Sci Pollut Res
banana peelbased biochar as a sustainable and robust ad-
sorbent for reduction of heavy metal from wastewater.
References
Ahmad T, Danish M (2018) Prospects of banana waste utilization in
wastewater treatment: a review. J Environ Manag 206:330348
Ahmad Z, Gao B, Mosa A, Yu H, Yin X, Bashir A, Ghoveisi H, Wang S
(2018) Removal of Cu(II), Cd(II) and Pb(II) ions from aqueous
solutions by biochars derived from potassium-rich biomass. J
Clean Prod 180:437449
Bouhamed F, Elouear Z, Bouzid J, Ouddane B (2016) Multi-component
adsorption of copper, nickel and zinc from aqueous solutions onto
activated carbon prepared from date stones. Environ Sci Pollut Res
23:1580115806
Ali A, Saeed K (2015) Phenol removal from aqueous medium using
chemically modified banana peels as low-cost adsorbent. Desal
Water Treat 57:1124211254
Cataldo S, Gianguzza A, Pettignano A, Villaescusa I (2013) Mercury(II)
removal from aqueous solution by sorption onto alginate, pectate
and polygalacturonate calcium gel beads. A kinetic and speciation
based equilibrium study. React Funct Polym 73:207217
Cutillas-Barreiro L, Paradelo R, Igrexas-Soto A, Núñez-Delgado A,
Fernández-Sanjurjo MJ, Álvarez-Rodriguez E, Garrote G, Nóvoa-
Muñoz JC, Arias-Estévez M (2016) Valorization of biosorbent ob-
tained from a forestry waste: competitive adsorption, desorption and
transport of Cd, Cu, Ni, Pb and Zn. Ecotoxicol Environ Saf 131:
118126
DeMessie B, Sahle-Demessie E, Sorial GA (2015) Cleaning water con-
taminated with heavy metal ions using pyrolyzed biochar adsor-
bents. Sep Sci Technol 50:24482457
Ding Y, Liu Y, Liu S, Li Z, Tan X, Huang X, Zeng G, Zhou Y, Zheng B,
Cai X (2016) Competitive removal of Cd (II) and Pb (II) by biochars
produced from water hyacinths: performance and mechanism. RSC
Adv 6:52235232
Godiya CB, Liang M, Sayed SM, Li D, Lu X (2019) Novel alginate/
polyethyleneimine hydrogel adsorbent for cascaded removal and
utilization of Cu
2+
and Pb
2+
ions. J Environ Manag 232:829841
EPA (1982) Electroplating and metal finishing effluent guidelines & stan-
dards. US Environmental Protection Agency. Available from: http://
www.epa.gov/electroplating-and-metal-finishing_proposed-rule_
08-31-1982_47-fr-38462.pdf.Accessed1June2019
Faheem YH, Liu J, Shen J, Sun X, Li J, Wang L (2016) Preparation of
MnOx-loaded biochar for Pb2+ removal: adsorption performance
and possible mechanism. J Taiwan Inst Chem Eng 66:313320
Fu F, Wang Q (2011) Removal of heavy metal ions from wastewaters: a
review. J Environ Manag 92:407418
Gazi M, Oladipo AA, Azalok KA (2018) Highly efficient and magneti-
cally separable palm seed-based biochar for the removal of nickel.
Sep Sci Technol 7:11241131
Giwa A, Dindi A, Kujawa J (2019) Membrane bioreactors and electro-
chemical processes for treatment of wastewaters containing heavy
metal ions, organics, micropollutants and dyes: recent develop-
ments. J Hazard Mater 370:172195
Hasan SH, Srivastava P (2009) Batch and continuous biosorption of Cu
2+
by immobilized biomass of Arthrobacter sp. J Environ Manag 90:
33133321
Ho YS (2006) Review of second-order models for adsorption systems. J
Hazard Mater 136:681689
Jia Y, Zhang Y, Fu J, Yuan L, Li Z, Liu C, Zhao D, Wang X (2019)
A novel magnetic biochar/MgFe-layered double hydroxides
composite removing Pb
2+
from aqueous solution: isotherms,
kinetics and thermodynamics. Colloids Surf A Physicochem
Eng Asp 567:278287
Jiang R, Tian J, Zheng H, Qi J, Sun S, Xi L (2015) A novel magnetic
adsorbent based on waste litchi peels for removing Pb(II) from
aqueous solution. J Environ Manag 155:2430
Lasheen MR, El-Sherif IY, Sabry DY, El-Wakeel ST, El-Shahat MF
(2015) Adsorption of heavy metals from aqueous solution by mag-
netite nanoparticles and magnetite-kaolinite nanocomposite: equi-
librium, isotherm and kinetic study. Desal Water Treat 57:17421
17429
Li Y, Bai P, Yan Y, Yan W, Shi W, Xu R (2019a) Removal of Zn
2+
,Pb
2+
,
Cd
2+
,andCu
2+
from aqueous solution by synthetic clinoptilolite.
Microporous Mesoporous Mater 273:203211
Li M, Liu H, Chen T, Dong C, Sun Y (2019b) Synthesis of magnetic
biochar composites for enhanced uranium (VI) adsorption. Sci Total
Environ 651:10201028
Liu C, Ngo HH, Guo W, Tung KL (2012) Optimal conditions for prep-
aration of banana peels, sugarcane bagasse and watermelon rind in
removing copper from water. Bioresour Technol 119:349354
Milenkovic DD, Milosavljevic MM, Marinkovic AD, Dokic VR,
Mitrovic JZ, Bojic AL (2013) Removal of copper (II) ion from
aqueous solution by high-porosity activated carbon. Water SA 39:
515522
Mohan D, Kumar H, Sarswat A, Alexandre-Franco M, Pittman CU Jr
(2014) Cadmium and lead remediation using magnetic oak wood
and oak bark fast pyrolysis bio-chars. Chem Eng J 236:513528
Mousavi SJ, Parvini M, Ghorbani M (2018) Adsorption of heavy metals
(Cu
2+
and Zn
2+
) on novel bifunctional ordered mesoporous silica:
optimization by response surface methodology. J TaiwanInst Chem
Eng 84:123141
Oladipo AA, Gazi M (2015a) Two-stage batch sorber design and optimi-
zation of biosorption conditions by Taguchi methodology for the
removal of acid red 25 onto magnetic biomass. Korean J Chem
Eng 32:18641878
Oladipo AA, Gazi M (2015b) Microwaves initiated synthesis of activated
carbon-based composite hydrogel for simultaneous removal of
copper(II) ions and direct red 80 dye: a multi-componentadsorption
system. J Taiwan Inst Chem Eng 47:125136
Oladipo AA, Gazi M, Yilmaz E (2015) Single and binary adsorption of
azo and anthraquinone dyes by chitosan-based hydrogel: selectivity
factor and Box-Behnken process design. Chem Eng Res Des 104:
264279
Oladipo AA (2018a) Microwave-assisted synthesis of high-performance
polymer based nanoadsorbents for pollution control. In: Hussain
CM, Mishra AK (eds) New polymer nanocomposites for environ-
mental remediation, vol 1. Elsevier, pp 337359
Oladipo AA (2018b) Bioinspired nanocomposites for adsorptive and
photo-assisted decontamination of wastewater. In: Hussain CM,
Mishra AK (eds) Nanotechnology in environmental science, vol 1.
Wiley-VCH Publishers, pp 685706
Oladipo AA (2018c) Biosynthesized and bio-inspired functional nano-
composites for pollution control. In: Hussain CM, Mishra AK (eds)
Nanocomposites for pollution control, vol 1. Pan Stanford
Publishers, pp 501525
Oladipo AA, Ifebajo AO (2018) Highly efficient magnetic chicken bone
biochar for removal of tetracycline and fluorescent dye from waste-
water: two-stage adsorber analysis. J Environ Manag 209:916
Oladipo AA, Ifebajo AO, Gazi M (2019) Magnetic LDH-based CoO
NiFe
2
O
4
catalyst with enhanced performance and recyclability for
efficient decolorization of Azo dye via Fenton-like reactions. Appl
Catal B Environ 243:243252
Pap S, Bezanovic V, Radonic J, Babic A, Saric S, Adamovic D, Sekulic
MT (2018) Synthesis of highly efficient functionalized biochars
from fruit industry waste biomass for the removal of chromium
and lead. J Mol Liq 268:315325
Environ Sci Pollut Res
... It is concluded that in the case of MB and SO dye adsorption, the % removal efficiency was enhanced from 89 to ~ 96%, 86 to 97.9%. This is because of the enhancement in the surface area of the adsorbent, which provides additional functional groups and more active sorption sites (Oladipo 2019). In case of CV dye, the % removal efficiency was increased from 95.77 to 98.27% by increasing the adsorbent loading from 0.005 to 0.01 g. ...
Article
Full-text available
In this study, a Pennisetum glaucum raw material (RM) based green bio-composite adsorbent containing 0.5% functionalized carbon nanotube (0.5% CNT + RM) was synthesized. The morphology and physicochemical properties of the bio-composite were explored using different techniques, such as Field emission scanning electron (FESEM), X-ray crystallography (XRD), Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), and Energy-dispersive X-ray spectroscopy (EDX). The adsorption efficiency of prepared bio-composite adsorbents was investigated for the efficient and effective removal of three cationic dyes such as methylene blue (MB), safranine O (SO), and crystal violet (CV) from single and multi-component systems. Batch adsorption experiments were performed to investigate the influence of different operational factors such as solution pH, initial dye concentration, adsorbent dosage, temperature, and contact time on the adsorption efficiency of dyes. In a single component, the process kinetics and adsorption behaviour of the adsorbent were well explained by the pseudo 2nd order kinetic model and Langmuir isotherm, giving a higher monolayer adsorption capacity of value, i.e., 510.96, 169.70, and 98.77 mg g⁻¹ for CV, SO, and MB dyes, respectively, at neutral pH conditions. The modified Langmuir isotherm model was employed to investigate the inhibiting effects of dyes in binary systems (MB + CV; CV + SO; SO + MB) and ternary systems (MB + CV + SO), which revealed the competitive behaviour of dyes. The adsorption process was feasible, exothermic, and physical in nature, involving H-bonding, π-π and electrostatic interactions. The regeneration studies of bio-composite showed excellent recovery capability, retaining their good adsorption efficiency after ten cycles of regeneration. Overall, a low-cost 0.5% CNT + RM bio-composite with excellent adsorption capacity in single and multi-component systems indicates its good potential for practical applications. Graphical abstract
... Although activated carbon is the most widely used commercial adsorbent, multiple investigations of silver removal by activated carbon or other synthetic and natural adsorbents challenged the commercialisation of such technology due to the cost-effectiveness and environmental footprint [27]. Biochar has been successfully used to remove numerous contaminants, such as antibiotics removal [31,32], phenols [33][34][35], and heavy metals [36,37] from wastewater. For example, a study investigated the application of biochar to adsorption of different heavy metals like copper, zinc and lead from the aqueous phase. ...
Article
Even low concentration monovalent silver (Ag +) and silver nanoparticles (Ag NPs) are emerging environmental threats, seeking an eco-friendly and cost-effective continuous treatment process to mitigate their pollution. In this study, an attempt has been made to investigate the potential of spent coffee grounds (SCGs) biochar in a fixed-bed column, to remove silver ions and silver nanoparticles from wastewater. A series (adsorption and desorption) of fixed-bed column experiments were performed under different operating conditions to determine the breakthrough curves (BTCs) and understand the effect of initial concentration (50-100 mg/L), the quantity of biochar (0.5-1 g), and the form of silver Ag + and Ag NPs on biochar removal capacity. Thomas and Yoon-Nelson models were applied to simulate different column parameters, such as breakthrough time, saturation time, the volume of treated effluent, and percentage of removal. These simulated results could assist in the scale-up of the process for an actual industrial operation. Experimental data showed good agreement with both Thomas and Yoon-Nelson models, where the simulated values were closely matched with the experimental values. Biochar was collected after the adsorption and characterised to confirm the morphology, crystal structure, and ionic state of silver. The saturated column was regenerated by 0.05 M HNO 3 as eluent and used at least 3 times with 15% capacity loss compared to initial performance, which demonstrated the viability and effectiveness of the biochar adsorption process.
Article
This study aims to remove Copper (Cu(II)) and Chromium (Cr(VI)) from aqueous solution using activated carbon (AC) from fennel seeds and potassium permanganate (KMnO4) treated fennel seeds. The activated carbon adsorbents were prepared from fennel seeds at different temperatures (500, 600 and 700°C). These adsorbents were designated as FS-500, FS-600 and FS-700. Each adsorbent was then chemically treated with KMnO4 solution to develop activated adsorbents, KMFS-500, KMFS-600 and KMFS-700. These six adsorbents were used for the binary adsorption of Cu(II) and (Cr(VI)) from an aqueous solution. The adsorbents were characterized by FTIR, SEM, UV-Vis and XRD. FTIR confirmed the presence of oxygen functional groups such as hydroxyl (-OH), carboxyl (-COOH) and carbonyl (-C = O) on the surface of the adsorbents. XRD confirmed a decrease in crystallinity as the temperature increased. SEM images showed that the morphology of the adsorbents was porous. KMFS-700 and FS-700 adsorbed more Cu(II) and Cr(VI) ions than KMFS-600, KMFS-500, FS-600 and FS-500. The maximum adsorption capacities for Cu(II) and Cr(VI) by FS-700 were 19.886 and 8.510 mg/g; for FS-600, it was 15.423 and 1.202 mg/g, and for FS-500, it was 16.921 and 1.722 mg/g, respectively. The maximum adsorption capacities for Cu(II) and Cr(VI) by KMFS-700 were 19.786 and 10.572 mg/g; for KMFS-600 it was 15.735, 8.109 mg/g, and for KMFS-500, it was 17.648 and 3.479 mg/g, respectively. All the adsorbents showed a stronger affinity for Cu(II) than Cr(VI). Kinetic studies showed that Cu(II) and Cr(VI) adsorption followed a pseudo-second-order reaction confirming that a chemical process controlled adsorption.
Article
Full-text available
Converting peanut and sheanut shells into biochar is a smart strategy for recycling agricultural waste. Biochar was produced from peanut and sheanut shells at temperatures of 350 ± 5°C and 700 ± 5°C. The adsorption capacities for lead (Pb 2+), cadmium (Cd 2+) and mercury (Hg 2+) in the binary systems were evaluated. In the binary systems with concentrations of 5 : 5 mg/L, 10 : 10 mg/L, 25 : 25 mg/L and 50 : 50 mg/L the removal efficiencies of GB350, SB350, GS350, GB700, SB700 and GS700 were 100% for Pb 2+ and 88.70% to 99.46% for Cd 2+ , 98.20% to 100% for Pb 2+ and 100% for Hg 2+ , 79.30% to 100% for Cd 2+ and 99.96% to 100% for Hg 2+. The higher adsorption percentages of Pb 2+ , Cd 2+ and Hg 2+ by the biochar in the binary systems indicated that the pH values of the solutions were good and suitable for adsorption. The biochar from peanut and sheanut shells showed excellent capacity to remove Pb, Cd and Hg in the binary systems. The Langmuir model (0.3351 ≤ R 2 ≤ 0.9901) was more suitable than the Freundlich model (0.0014 ≤ R 2 ≤ 0.9994) for the adsorption of toxic metal ions onto the biochar in the binary systems. The interactive effects of the binary mixtures in the aqueous solution of Pb 2+ , Cd 2+ , and Hg 2+ were found to be either antagonistic or synergistic. Peanut and sheanut shell biochar were rich in calcium, potassium, magnesium, and sodium, and phosphates affected the mechanisms of Pb and Cd adsorption. The high sulphur content might have influenced the mechanism of Hg adsorption in the aqueous solutions on peanut and sheanut shell biochar. These results suggest that peanut and sheanut shell biochar have enormous potential and are suitable for adsorption of Pb 2+ , Cd 2+ and Hg 2+ in wastewater and polluted soil. Therefore, their effectiveness should be further tested in an actual water polluted environment.
Article
Efficient removal of tetracycline (TC) has become a global challenge because the unsatisfactory removal rate of traditional sewage treatment technology. A carbon-based material (MoS2@SBC) was synthesized by one-pot hydrothermal method using municipal sludge as the feedstock to remove TC from water. Characterization analysis showed that MoS2@SBC had abundant functional groups (e.g., -OH, CO, SH) and large surface area. The maximum adsorption capacity of MoS2@SBC for TC could reach 229.2 mg/g at 298 K. Elovich model and Langmuir model better fitted the kinetics and isotherms data, respectively, which illustrated that chemisorption dominated the process of TC adsorption onto MoS2@SBC. Liquid film diffusion and intraparticle diffusion simultaneously controlled the adsorption process. The thermodynamics study described that adsorption was a spontaneous, endothermic and randomness increasing process. The ionic species/strength and solution pH were the critical factors affecting the adsorption process. The kinetics, isotherms and thermodynamics analysis, together with characterization results demonstrated that π-π conjugation, H-bonding, electrostatic interaction and pore filling were the main adsorption mechanisms. Additionally, the adsorption capacity of MoS2@SBC for TC in the actual waters (Yangtze River water and Nanhu Lake water) was inhibited. Furthermore, NaOH regeneration could maintain the sustainable adsorption performance of MoS2@SBC. This study developed a promising adsorbent for TC removal and provided a resource utilization approach for sludge.
Article
An Unpredictable rise in greenhouse gas (GHG) emissions is a primary concern to the global scientific community. It is directly related to the rapid expansion of the human population and is associated with the immense energy demand. The combustion of hydrocarbon fuels in internal combustion (IC) engines releases a large amount of carbon dioxide (CO2), which is one of the causes of GHG emissions. Mitigation of CO2 emissions is a significant challenge to the world. Although several researchers have focused on capturing CO2 from power plants, some researchers have taken initiatives in recent times to capture CO2 in IC engines. This study particularly explored the possibility of using a biomass based‐adsorbent to capture CO2 in the exhaust of a diesel engine. Initially, activated carbon was obtained from palm shells by adopting the preparation methods such as (i) carbonization and (ii) chemical activation. Then, the produced activated carbon was analyzed to examine its physico‐chemical characteristics and surface textural properties by adopting characterization techniques. The adsorbent sample was loaded in an in‐house fabricated adsorption chamber which was attached to the exhaust of the test engine. The performance of palm shell‐based activated carbon was evaluated as a potential adsorbent for CO2 capture when the engine was operated with two distinct fuels, (i) 100 % diesel (D100) and (ii) an optimum biodiesel‐diesel blend (JME20) comprising 80 % D100 and 20 % Jatropha Methyl Ester (JME). The experimental results showed that an average of about 30 % and 37 % of CO2 was captured by using palm shell‐based adsorbent in D100 and JME 20 operations, respectively. This article is protected by copyright. All rights reserved.
Article
The excessive and indiscriminate use of agrochemicals, such as paraquat (PQ), leads to numerous water pollution problems. The adsorption of aqueous contaminants is one of the most effective methodologies for water purification. This study develops nanocomposite biopolymeric hydrogels of chitosan and clay, and examines the biosorption capacity of PQ from aqueous matrices. The main objective of the work is to achieve a biocomposite with great biosorbent characteristics and low cost. The nanocomposite hydrogels were synthesized by simple techniques and characterized by aqueous absorption capacity, differential scanning calorimetry, thermogravimetric analysis, infrared spectroscopy, X-ray diffraction, microscopic and texture techniques, and surface charge analysis. Besides, their performance in the removal of PQ from aqueous systems was studied in discontinuous tests under different conditions. The results showed maximum adsorption capacities of 0.06, 0.98, 0.94 and 0.99 mg·g⁻¹ for CS, CS/DDA, CS/Bent and CS/LVF beads, respectively. The results showed that the presence of clay is essential for PQ sorption to occur. Thermodynamic, kinetic, and isothermal studies of the nanocomposite beads indicated that biosorption occurred spontaneously and that it has the participation of exothermic physisorption and chemisorption processes, corresponding mainly to the pseudo-second-order kinetic model, and to the Langmuir and Freundlich isothermal models. The CS hydrogel showed a non-spontaneous sorption process associated with the physisorption of PQ on the beads. The tests showed hopeful results for the utilization of the developed nanocomposite hydrogels as PQ biosorbents, with novel properties and low-cost characteristics, which are a sustainable and promising solution for the generation of pollutant-free water.
Article
Xanthates are largely used in the mining industry as mineral flotation agents, causing serious environmental problems, and therefore, removing them effectively is a significant barrier for sustainable green mining that needs to be addressed. Here, nanostructured mesoporous CoFe2O4/Co3Fe7@carbon prepared by clean and facile mechanochemical-molten salt process is employed as a trifunctional magnetic adsorbent-photocatalyst agent (M-APh) for the efficient adsorption of potassium ethyl xanthate (KEX) from its solutions in dark, and the photocatalytic degradation of the compound under LED-light irradiation. The surface- and bulk‑carbon content of M-APh is evaluated to be around 88 and 80 wt%, with the surface area of 355 m²/g and the average pore size of 3.7 nm, enabling the adsorption of 6.12 wt% KEX on its surfaces in dark. The ferromagnetic performance of M-APh, characterized by the coercivity (Hc), saturation magnetization (Ms) and remnant (Mr) values of 735 Oe, 17.9 emu/g and of 6.1 emu/g, respectively, is an asset supporting the facile separation of the agent from its suspensions. The effects of various parameters including the concentration of KEX in the solution, the dosage of M-APh, the wavelength of the LED-light, and the initial pH on the KEX removal performance of M-APh are studied. Within 5 h of LED-light irradiation of wavelengths 450, 385 and 365 nm, the KEX removal rates are recorded at 96.59, 98.61 and 99.49 %, respectively. Possible mechanisms involved in the adsorption and photocatalytic degradation of KEX are discussed.
Article
Hydrogen peroxide is a useful molecule in biological and chemical reactions, but in excess harmful. Developing simple, low cost, and quick analytical method capable of detecting H2O2 is still critical. In this proposed work, our main objective was to synthesize nanocomposite of Musa paradisiaca L. peels (MPLP) by fine tuning its structure and properties with magnetite (Fe3O4). The characterization study, such as UV–Vis, FT-IR, SEM, EDX, XRD, VSM, Zeta potential, and BET were carried out effectively. The change in color from the initial grey to blue could be observed with naked eye (approximately 30 s) and the sensor established a colorimetric response in a relatively wide range of 0.01 μM to 0.9 mM with a lower detection limit (LOD) of 0.008 μM and limit of quantitation (LOQ) of 0.02 μM. Interference tests (using cations and organic chemicals) and real samples application (Tap water and milk) were used to evaluate the sensor's selectivity with recovery values ranging from 96 to 99% close to the H2O2 detection endpoint. The MPLP nanocomposite reflected a strong peroxidase-like activity for 3, 3, 5, 5, tetramethylbenzidine (TMB) oxidation in the presence of H2O2, having enzyme mimicking properties. Our study established a sensitive and selective optical sensing platform based on the green plant material for H2O2 detection.
Article
Full-text available
Organics and heavy metals are common pollutants in many wastewaters and water bodies. Adsorption processes by magnetic materials can rapidly remove these pollutants from water and effectively recycle adsorbent. In this study, magnetic analyzer, X-ray diffraction, Flourier transform infrared spectroscopy, and granulometry were used to characterize the synthesized magnetic reed biochar materials (ZnFe2O4/biochar). Influences of adsorption time, pH, temperature, initial solution concentration, and adsorption equilibrium concentration on adsorption performances were investigated for Cu²⁺ and phenol adsorption by ZnFe2O4/biochar. Adsorption kinetic and isotherm models were used to describe the adsorption processes. Adsorption of phenol and Cu²⁺ by ZnFe2O4/biochar reached saturation within 45 min and increased slightly with the increase of temperature from 15 to 45 °C. Adsorption of Cu²⁺ increased with the increase of pH, while the adsorption of phenol peaked at pH = 6. The adsorption processes fit the pseudo-second order kinetics model, and both conformed to the Langmuir model. The fitting results show that the maximum single-component adsorption capacity of phenol and Cu²⁺ by ZnFe2O4/biochar is 63.29 and 12.20 mg/g, and the maximum bi-component adsorption capacity reaches 40.16 and 9.48 mg/g, respectively. All the findings demonstrate that ZnFe2O4/biochar has good adsorption performance for phenol and Cu²⁺.
Article
Full-text available
The magnetic biochar (γ-Fe 2 O 3 @BC) derived from banana peels was synthesized by a facile one-pot thermal process and used as the cost-effective and recyclable persulfate (PS) activator for organic contaminants degradation. The results showed that the encapsulated iron oxide nanoparticles not only introduced the magnetism into biochar for easy separation, but also influenced the catalytic ability for PS activation. The γ-Fe 2 O 3 @BC was found to be highly effective for bisphenol A (BPA) degradation without pH adjustment. A complete removal of BPA was obtained within 20 min with an observed rate constant (k obs ) of 0.1849 min ⁻¹ , which was almost two times as large as that (0.0956 min ⁻¹ ) of pure biochar. Further, it exhibited high mineralization efficiency for the degradation of various organic contaminants. The high catalytic activity could be attributed to large BET surface area, dispersed iron species, abundant oxygen functional groups and rich doped nitrogen. Radical quenching experiments and electron spin resonance (ESR) studies confirmed that OH[rad], SO 4[rad]− and O 2[rad]− were all involved in the radical oxidation process which was responsible for BPA degradation. A mechanism of PS activation by the γ-Fe 2 O 3 @BC catalyst was proposed based on the synergistic effect of biochar and iron.
Article
Full-text available
In this work, a novel biochar was prepared from the Artemisia argyi stem at 300 °C (AS300), 450 °C (AS450), and 600 °C (AS600). The structural properties of these biochars were characterized with various tools. The sorption kinetic processes of Cr(VI) and Cu(II) onto these biochars were better described by the pseudo-second order. The sorption isotherm processes of Cr(VI) onto these biochars were better described by the Freundlich model while the adsorption processes of Cu(II) were consistent with the Langmuir model. Batch sorption experiments showed that AS600 had the maximum adsorption capacity to Cr(VI) and Cu(II) with 161.92 and 155.96 mg/g, respectively. AS600 was selected for the follow-up batch and dynamic adsorption experiments. Results showed that AS600 had larger adsorption capacity for Cr(VI) at lower pH while the larger adsorption capacity for Cu(II) was found at higher pH. The effect of ionic strength on the adsorption of Cu(II) by AS600 was greater than that on the adsorption of Cr(VI). Dynamic adsorption experiments showed that Cu(II) had a higher affinity for the adsorption sites on the AS600 compared with Cr(VI). The adsorption mechanisms mainly involved electrostatic attraction, ion exchange, pore filling, and chemical bonding effect. Graphical abstract
Article
Full-text available
Heavy metal ion pollution leads to severe health risk to human beings. Herein, a natural and highly efficient sodium alginate (ALG)/polyethyleneimine (PEI) composite hydrogel was designed and fabricated for the removal of heavy metal ions from wastewater. The adsorption of heavy metal ions on the ALG based, 3D composite hydrogel were thoroughly investigated in this study. Furthermore, the in situ reduced metal nanoparticle-loaded ALG/PEI composite hydrogel provided us a sustainable utilization route of the heavy metal ion with a promising adsorption-catalysis ability. In general, this research will present an effective and practical paradigm for the cascaded treatment and recycling of heavy metal ions in wastewater.
Article
Full-text available
Magnetic CoO–NiFe2O4 catalyst was successfully fabricated from layered double hydroxide through a simple co-precipitation and calcination method, and for the first time applied as a novel Fenton-like catalyst for the decolorization of Eriochrome black T dye (EB). The characteristics results demonstrated that CoO–NiFe2O4 exhibits a broad pore size distribution in the range of 5–40 nm, large specific surface area (363.6 m2 g–1) with the high structural stability and saturation magnetization (83.2 emu g–1), hence, can be easily recycled for five subsequent runs without significant activity loss. The catalytic activity of CoO–NiFe2O4 was systematically evaluated under varying reaction conditions including initial pH, catalyst dosage, initial dye and H2O2 concentrations. Under the optimal conditions, the CoO–NiFe2O4 accomplished ~87–97% decolorization of EB within 120 min. Here, the possible catalytic mechanism for EB decolorization is proposed and concluded to be multi-process induced by OH, O2− or h + in the Fenton-like system.
Article
Full-text available
As a toxic and metalloid substance, excess arsenic (As) can cause serious harm to the environment and public health. In this work, crayfish shell biochar (CFS450) and modified biochar (MCFS450) were prepared to remove As(V) from aqueous solutions under various conditions. Compared to CFS450, MCFS450 had a higher specific surface area, better pore structure, and higher As(V) adsorption capacity. Based on the Langmuir model, its maximum As(V) adsorption capacity was 17.2 mg/g. The biochar had a large number of surface functional groups such as C-O, O-H, and -OH. After modification, a certain mass of ZnO nanoparticles existed on MCFS450, which increased positive charge on the surface and promoted the adsorption of As(V). As the temperature rose, the adsorption capacity increased, suggesting the adsorption was endothermic. Under low PH conditions, the adsorption effect was better. When Cl−, HCO3−, SO42−, and PO43− respectively existed, the adsorption capacity decreased, indicating that As(V) competed with other anions. The column adsorption experiments showed that Thomas, Yoon-Nelson, and Adams-Bohart models can be expressed as a unified model (EXY model). The EXY model can be used for the design of biochar-based filter for As(V) removal, providing a theoretical basis for practical production applications. Experimental setup and results of column adsorption.
Article
An absorbent, magnetic biochar supporting MgFe-Layered double hydroxides (MgFe-LDH) composites was synthesized to remove Pb²⁺ from the aqueous solution. The results of SEM, EDS, XRD, FT-IR, XPS, VSM and BET determinations showed that MgFe-LDH was successfully loaded on the magnetic biochar by hydrothermal synthesis. These characterizations also indicated that the adsorption of Pb²⁺ resulted from co-precipitation between interlayer anions, surface hydroxyl groups and Pb²⁺. The isotherms study revealed that the adsorption of Pb²⁺ on magnetic biochar/MgFe-LDH was well fitted to Langmuir model. The maximum adsorption capacity was 476.25 mg g⁻¹ at 25 °C. Kinetic and thermodynamic studies indicated that the adsorption process was a spontaneous endothermic reaction and limited by chemisorption. Owing to the simple synthesis, superior adsorption capacity, good magnetic properties and cyclic utilization, the magnetic biochar/MgFe-LDH is a promising adsorbent for removing Pb²⁺ from aqueous solution.
Article
Heavy metal ion pollution leads to severe health risk to human beings. Herein, a natural and highly efficient sodium alginate (ALG)/polyethyleneimine (PEI) composite hydrogel was designed and fabricated for the removal of heavy metal ions from wastewater. The adsorption of heavy metal ions on the ALG based, 3D composite hydrogel were thoroughly investigated in this study. Furthermore, the in situ reduced metal nanoparticle-loaded ALG/PEI composite hydrogel provided us a sustainable utilization route of the heavy metal ion with a promising adsorption-catalysis ability. In general, this research will present an effective and practical paradigm for the cascaded treatment and recycling of heavy metal ions in wastewater.
Article
Magnetic biochar composites were successfully fabricated by pyrolysis of siderite and rice husk under N2 condition. The results of a variety of characterization implied magnetic biochar displayed porous structures with larger specific surface area. The batch adsorption experiments showed high adsorption properties of magnetic biochar composites toward U(VI) (52.63 mg/g at pH 4.0), whereas U(VI) adsorption was significantly influenced by Na2CO3 and HA. U(VI) adsorbed onto magnetic biochar was reduced to U(IV) by Fe3O4 according to XPS and XANES analyses. In addition, no significant effect of ionic strength of NaCl and EXAFS results, illustrated the inner-sphere surface complexation of U(VI) on magnetic biochar. Owing to the simple synthesis procedure, low cost, high adsorption efficiency, easy separation and environmental friendly, magnetic biochar can be considered as a potential adsorbent for the purification of U(VI)-bearing wastewater in environmental remediation.
Article
The dye and heavy metal are two principal concomitant pollutants in industrial wastewaters, posing a serious threat to public health and the environment. Herein, we developed a novel strategy to convert banana peels into hierarchically porous carbon (BPCA) and porous carbon oxide (BPCAO) for the simultaneous removal of methylene blue (MB) and Co(II). The as-prepared carbons were systematically characterized by SEM, TEM, BET, FT-IR and XPS. Compared to BPCA, BPCAO showed a better adsorption performance due to its abundant surface oxygen-containing groups. In the mono-component systems, both MB and Co(II) adsorption onto BPCAO were well described by the pseudo-second-order and Langmuir models. The maximum adsorption capacities of MB and Co(II) were calculated to be 1303.54 and 122.39 mg/g at 298 K, respectively. In the binary system, the interaction between MB and Co(II) was determined and it depended on the initial concentration of Co(II). The adsorption mechanism of MB involved electrostatic interaction, π-π stacking and hydrogen-bonding while that of Co(II) was mainly ruled by the complexation and/or ion-exchange. This study indicated BPCAO could be a favorable biomass-derived adsorbent for the simultaneous removal of the dye and heavy metal.
Article
Coal fly ash-derived zeolites have attracted considerable interest in the last decade due to their use in several environmental applications such as the removal of dyes and heavy metals from aqueous solutions. In this work, coal fly ash-derived zeolites and silver nanoparticles-impregnated zeolites (nanocomposites) were synthesized and characterized by TEM/EDX, SEM/EDX, XRD, XRF, porosimetry (BET), particle size analysis (PSA) and zeta potential measurements. The synthesized materials were used for the removal of Hg2+ from aqueous solutions. The results demonstrated that nanocomposites can remove 99% of Hg2+, up to 10% and 90% higher than the removal achieved by the zeolite and the parent fly ash, respectively. Leaching studies further demonstrated the superiority of the nanocomposite over the parent materials. The Hg2+ removal mechanism is complex, involving adsorption, surface precipitation and amalgamation.