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Adsorption studies on fruits of Gular (Ficus glomerata): Removal of Cr(VI) from synthetic wastewater

Department of Applied Chemistry, Faculty of Engineering and Technology, Aligarh Muslim University, Aligarh, UP, India.
Journal of hazardous materials (Impact Factor: 4.53). 09/2010; 181(1-3):405-12. DOI: 10.1016/j.jhazmat.2010.05.025
Source: PubMed

ABSTRACT

The adsorption of Cr(VI) was studied in batch system using fruits of Ficus glomerata as adsorbent. The effect of temperature, pH, initial Cr(VI) concentration and time was investigated. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) was used to investigate surface morphology and active functional groups present on the adsorbent surface. Thermodynamic parameters like free energy change (DeltaG(0)), enthalpy (DeltaH(0)) and entropy (DeltaS(0)) indicate the spontaneous, endothermic and increased randomness nature of Cr(VI) adsorption. Equilibrium data were fitted well with Langmuir isotherm at 50 degrees C. The magnitude of mean free energy indicates chemical nature of adsorption. The breakthrough and exhaustive capacities were found to be 5 and 23.1 mg g(-1) respectively. The applicability of the adsorbent has been demonstrated by removing Cr(VI) from electroplating wastewater.

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    • "Toxic heavy metals in natural water bodies are hazardous to environment and living organisms due to their persistence and bioaccumulation through food chain (Rao and Rehman 2010;Kuppusamy et al. 2016b). Various chronic diseases are caused by zinc, copper, and chromium (Cr) which are considered to be the most dreadful heavy metals. "
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    ABSTRACT: The efficiency of low-cost, abundantly available local forestry waste, oak (Quercus robur) acorn peel (OP), to remove toxic Cr(VI) from aqueous solutions was studied in a batch system as a function of contact time, adsorbate concentration, adsorbent dosage, and pH. In an equilibrium time of 420 min, the maximum Cr removal by OP at pH 2 and 10 was 100 and 97 %, respectively. The sorption data fitted well with Langmuir adsorption model. Evaluation using Langmuir expression presented a monolayer sorption capacity of 47.39 mg g−1 with an equilibrium sorbent dose of 5 g L−1 and pH 7. Uptake of Cr by OP was described by pseudo-second-order chemisorption model. ICP-OES, LC-ICPMS analysis of the aqueous and solid phases revealed that the mechanism of Cr(VI) removal is by ‘integrated adsorption and reduction’ mechanism. ESEM-EDX and XRD analysis of OP before and after adsorption also confirmed that both adsorption and reduction of Cr(VI) to less toxic Cr3+ forms followed by complexation onto the adsorbent surface contributed to the removal of Cr(VI). Consistent with batch studies, OP effectively removed (>95 %) Cr from the real water samples collected from lake and sea. The results of this study illustrate that OP could be an economical, green, and effective biomaterial for Cr(VI) removal from natural aquatic ecosystems and industrial effluents.
    Full-text · Article · Feb 2016 · Water Air and Soil Pollution
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    • "Although a slight increase in Cr(VI) removal with decreasing pH and increasing temperature was observed, the differences were not that significant after 2 h. Previous researchers reported using ash gourd peel waste (Sreenivas et al., 2014), olive pomace (Malkoc, 2006) and Gular fruits (Rao and Rehman, 2010), finding that the optimum pH was 1–3 for maximum Cr(VI) removal and the reactions were either endo or exothermic in character. In this study, the adsorbent had a relatively higher and broader working pH and temperature range. "
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    ABSTRACT: The present study describes for the first time the utilization of dried twigs of Melaleuca diosmifolia, fallen off from the plant, to detoxify and remove hexavalent chromium or Cr(VI) from aqueous systems. Initial characterization by gas chromatography revealed that the selected biomaterial is one of the natural sources of eucalyptol. It constituted high concentrations of reducing compounds (iron, phenols and flavonoids). Batch studies revealed that the biosorbent (5 g L−1) was able to remove 97-99.9% of 250 mg L−1 Cr(VI) at wide-ranging pH (2-10) and temperature (24-48 °C). Adsorption kinetics was well described using the pseudo-second-order kinetic model, while the equilibrium adsorption data were interpreted in terms of the Langmuir isotherm model. The monolayer adsorption capacity was 62.5 mg g−1. Both inductively coupled plasma optical emission spectrometry and liquid chromatography analyses of the aqueous and solid phases revealed that the mechanism of Cr(VI) removal was ‘adsorption-coupled reduction’. Scanning electron microscope, infrared spectroscopy and x-ray diffraction analyses of the biosorbent before and after adsorption also confirmed that both adsorption and reduction of Cr(VI) to Cr(III) followed by complexation onto functional groups of the active surface contributed to the removal of Cr(VI) from aqueous solution. The selected biomaterial effectively (99.9%) removed Cr(VI) in lake and sea water samples, highlighting its potential for remediating Cr(VI) in real environmental conditions.
    Full-text · Article · Jan 2016 · Process Safety and Environmental Protection
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    • "However, the adsorption process is an attractive alternative due to its ease of operation, economic viability and effectiveness. Recently, adsorptive removal of Cr(VI) from wastewater using various adsorbents has been investigated by several workers (Ren et al., 2013; Ozer et al., 2012; Gupta et al., 2013; Shukla and Vankar, 2012; Annalisa et al., 2012; Rao et al., 2012; Borah et al., 2012; Khan and Singh, 2010; Rao and Rehman, 2010). It was observed that most of these adsorbents have limited applicability due to their low adsorption capacities, prolonged contact time and inability to work at natural pH of water. "
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    ABSTRACT: Guar gum–nano zinc oxide (GG/nZnO) biocomposite was used as an adsorbent for enhanced removal of Cr(VI) from aqueous solution. The maximum adsorption was achieved at 50 min contact time, 25 mg/L Cr(VI) conc., 1.0 g/L adsorbent dose and 7.0 pH. Langmuir, Freundlich, Dubinin–Kaganer–Radushkevich and Temkin isotherm models were used to interpret the experimental data. The data obeyed both Langmuir and Freundlich models (R2 = 0.99) indicating a multilayer adsorption of Cr(VI) onto the heterogeneous surface. The linear plots of Temkin isotherm showed adsorbent-adsorbate interactions. Moreover, the energy obtained from DKR isotherm (1.58–2.24 kJ/mol) indicated a physical adsorption of the metal ions onto the adsorbent surface, which implies more feasibility of the regeneration of the adsorbent. GG/nZnO biocomposite adsorbent showed an improved adsorption capacity for Cr(VI) (qm = 55.56 mg/g) as compared to other adsorbents reported in the literature. Adsorption process followed pseudo-second order kinetics; controlled by both liquid-film and intra-particle diffusion mechanisms. Thermodynamic parameters (ΔGo, ΔHo and ΔSo) reflected the feasibility, spontaneity and exothermic nature of adsorption. The results suggested that GG/nZnO biocomposite is economical, eco-friendly and capable to remove Cr(VI) from natural water resources.
    Full-text · Article · Sep 2013 · Arabian Journal of Chemistry
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