Shams Ali Baig

Environmental Engineering

28.96

Publications

  • Jin Zhu · Zhimo Lou · Yu Liu · Ruiqi Fu · Shams Ali Baig · Xinhua Xu
    [Show abstract] [Hide abstract]
    ABSTRACT: Iron-manganese binary oxide (FeMnOx) is considered highly effective for arsenic adsorption, however, the agglomeration effect hindered its practical application. In this study, graphene has been used as a supporting matrix to disperse FeMnOx due to its huge specific surface area, and the synthesized novel composite adsorbent (FeMnOx/RGO) was employed for arsenic removal. Results demonstrated that FeMnOx/RGO (mass ratio of FeMnOx to FeMnOx/RGO nanocomposites is 45%) has larger specific surface area (411 m2 g-1) in comparison with bare FeMnOx, and showed 10.16 mg As g-1 FeMnOx and 11.49 mg As g-1 FeMnOx adsorption capacities for As(III) and As(V), respectively, with 1 mg L-1 initial concentration. Increased in the initial concentration to 7 mg L-1, the adsorption capacities of As(III) and As(V) reached to 47.05 mg As g-1 FeMnOx and 49.01 mg As g-1 FeMnOx, respectively. The removal process perfectly obeys pseudo second-order kinetic model for both As(III) and As(V). And PO43- was found to strongly inhibit arsenic adsorption. Furthermore, adsorption tests and characterization analyses confirmed that MnO2 played a key role on the oxidation of As(III), while iron(III) oxide was found crucial to As(V) removal. Electrostatic interaction and surface complexation mechanisms involved in the adsorption. These findings suggested that the adsorbent could be used in real arsenic-contaminated water treatment.
    RSC Advances 08/2015; DOI:10.1039/C5RA11601E · 3.84 Impact Factor
  • Jin Zhu · Shams Ali Baig · Tiantian Sheng · Zimo Lou · Zhuoxing Wang · Xinhua Xu
    [Show abstract] [Hide abstract]
    ABSTRACT: In this study, a novel composite adsorbent (HBC–Fe3O4–MnO2) was synthesized by combining honeycomb briquette cinders (HBC) with Fe3O4 and MnO2 through a co-precipitation process. The purpose was to make the best use of the oxidative property of MnO2 and the adsorptive ability of magnetic Fe3O4 for enhanced As(III) and As(V) removal from aqueous solutions. Experimental results showed that the adsorption capacity of As(III) was observed to be much higher than As(V). The maximum adsorption capacity (2.16 mg/g) was achieved for As(III) by using HBC–Fe3O4–MnO2 (3:2) as compared to HBC–Fe3O4–MnO2 (2:1) and HBC–Fe3O4–MnO2 (1:1). The experimental data of As(V) adsorption fitted well with the Langmuir isotherm model, whereas As(III) data was described perfectly by Freundlich model. The pseudo-second-order kinetic model was fitted well for the entire adsorption process of As(III) and As(V) suggesting that the adsorption is a rate-controlling step. Aqueous solution pH was found to greatly affect the adsorption behavior. Furthermore, co-ions including HCO3− and PO43− exhibited greater influence on arsenic removal efficiency, whereas Cl−, NO3−, SO42− were found to have negligible effects on arsenic removal. Five consecutive adsorption-regeneration cycles confirmed that the adsorbent could be reusable for successive arsenic treatment and can be used in real treatment applications.
    Journal of Hazardous Materials 04/2015; 286. DOI:10.1016/j.jhazmat.2015.01.004 · 4.33 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Wet flue gas desulfurization (WFGD) system has been increasingly recognized to be effective in Hg removal. But the generated secondary pollution due to Hg re-emission from desulfurization solutions or solid byproducts has received researchers’ attention. In this paper, the distribution of captured Hg2+(L) in the simulated WFGD slurry was studied as a function of various environmental factors. Experimental results indicated that the pH value had a strong effect on Hg2+ reduction but had negligible influence on the Hg2+ retention by the grained fraction of gypsum. Increasing in pH value resulted in higher Hg2+ reduction and over 46% of Hg2+ was found to be reduced into Hg0 at pH 5.0. Besides, increased slurry temperature also promoted the Hg2+ reduction and Hg0 re-emission as well as the Hg2+ retention efficiency by gypsum. Other factors including S (IV), Cl− and NO3− concentration was found to inhibit Hg2+ transformation into Hg0 but slightly promoted the Hg2+ retained in gypsum. Moreover, the addition of sodium sulfide (Na2S), 2,4,6-trimercaptotiazine, trisodium salt nonahydrate (TMT), and sodium dithiocarbamate (DTCR) prevented the Hg2+ reduction and precipitated out as insoluble HgS, Hg3(TMT)2 and Hg(DTCR)2 on gypsum. The findings presented in this study could provide theoretical basis for Hg removal in coal-fired power plants.
    Fuel 01/2015; 140:136–142. DOI:10.1016/j.fuel.2014.09.094 · 3.41 Impact Factor
  • Shams Ali Baig · Jin Zhu · Lisha Tan · Xiaoqin Xue · Chen Sun · Xinhua Xu
    [Show abstract] [Hide abstract]
    ABSTRACT: Elevated concentration of arsenic in water supplies is detected worldwide and therefore becomes a global issue. Calcination process is known to increase the adsorbent hardness for its effective application in column-based treatment. In this study, magnetic honeycomb briquette cinders (MHBC) and its calcined products: MHBC(A) and MHBC(N) were employed for the adsorptive removal of As(III) in fixed-bed column. Characterizations revealed that the calcination at 1000 degrees C under nitrogen has significantly increased the adsorbent particles size; favored phase transformation and improved saturation magnetization (>20 emu g(-1)). Additionally, the new iron silicate phase (Fe2SiO4) in aqueous medium generated highly reactive iron oxide species (=FeOOH), which effectively bind As(III) from the influent water by ligand exchanges. In contrast, calcination under dynamic air drastically reduced the saturation magnetization (<1 emu g(-1)) and assisted to form segregated magnetite, quartz and hematite, as revealed in XRD patterns. The breakthrough curve of each column was compared with Thomas model and found that the model could be applied to estimate As(III) adsorption in fixed-bed column. Thomas model suggested parameters follow the order: MHBC(N) > MHBC > MHBC(A) and the maximum solid phase concentration (q(T)) was found to be about 56.07 mg g(-1) for MHBC(N). The column beds could be successfully regenerated using 200 bed volume of 10% NaOH solution. This study suggests that the selective calcination process need to be integrated with the adsorbent development process for the efficient removal of As(III) from contaminated water using column-based treatment.
    Chemical Engineering Journal 12/2014; 257:1–9. DOI:10.1016/j.cej.2014.06.117 · 4.32 Impact Factor
  • Shams Ali Baig · Jin Zhu · Niaz Muhammad · Tiantian Sheng · Xinhua Xu
    [Show abstract] [Hide abstract]
    ABSTRACT: Magnetic biochar is increasingly known as a multi-functional material and the appropriate synthesis method further increase its efficient applications. In this study, the effects of synthesis methods on the fabrication of Kans grass straw/biochar (KGS/KGB) with Fe3+/Fe2+ by chemical co-precipitation and subsequently pyrolyzing at 500 °C for 2 and 4 h were studied in details, and compared their As(III, V) adsorption potentials under different operating conditions. Magnetic biochars (MKGB3 and MKGB4) prepared from KGS revealed of superior Fe3O4 loading, higher As(III, V) adsorption efficiency and saturation magnetization (45.7 Am2 kg−1) than that of KGB (MKGB1 and MKGB2). Moreover, Thermogravimetric analysis (TGA) demonstrated three stages of decomposition and the MKGB3 and MKGB4 generated higher residual mass (>60%) at stage 3 (1000 °C) due to greater Fe3O4 composite in biochar matrix and turned to be thermally more stable. As(III) and As(V) adsorption equilibrium data well fitted in Langmuir model and followed the order: MKGB4 > MKGB3 > MKGB2 > MKGB1. The maximum As(III) and As(V) adsorption capacities were about 2.0 mg g−1 and 3.1 mg g−1, respectively. The data best fitted in pseudo-second-order (R2 > 0.99) rather than pseudo-first-order kinetics model indicating of more complex mechanism. The adsorption of As(III) and As(V) was found to decrease with increasing in ionic strength of competing ions and PO43− was found to strongly inhibit arsenic adsorption. Highest desorption was achieved at pH 13.5 using NaOH. This study suggests that selective adsorbent synthesis method could be useful to prepare effective adsorbent for toxic metals immobilization.
    Biomass and Bioenergy 10/2014; 71. DOI:10.1016/j.biombioe.2014.09.027 · 3.41 Impact Factor
  • Chen Sun · Shams Ali Baig · Zimo Lou · Jin Zhu · Zhuoxing Wang · Xia Li · Jiahan Wu · Yifu Zhang · Xinhua Xu
    [Show abstract] [Hide abstract]
    ABSTRACT: Nanosized titanium nitride (nTiN) doped palladium/nickel (Pd/Ni) foam electrodes were successfully prepared via electroless deposition method. The electrodes were evaluated by different techniques including field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and linear sweep voltammetry (LSV). FE-SEM images demonstrated that two different morphologies existed in the Pd layer after nTiN doping. The nTiN doped Pd/Ni foam electrodes were found to be highly effective for electrochemical reductive dechlorination of 2,4-dichlorophenoxyacetic acid (2,4-D) with excellent activity and stability, as revealed by batch experiments. Under the conditions of nTiN doping content of 2 mg, Pd loading of 0.44 mg cm(-2), the energetic electrode achieved nearly 100% removal of 2,4-D (0.226 mmol L-1) within 2 h at a current density of 1.667 mA cm(-2). However, the removal efficiency reached only 57.13% when a normal Pd/Ni foam electrode with identical Pd loading and current density was utilized. A successive 2,4-D reductive dechlorination process was observed. o-Chlorophenoxyacetic acid (o-CPA), p-chlorophenoxyacetic acid (p-CPA) and phenoxyacetic acid (PA) were detected and identified as transformation products. Regression analysis proved that the pseudo-first order kinetic model was not suitable to describe the dechlorination process on nTiN doped Pd/Ni foam electrodes due to the appearance of a plateau in the beginning of the curve. Moreover, an adsorption theory for Pd chemisorption of active hydrogen atom was proposed to better explain the phenomenon. An adsorption equilibrium of hydrogen existed in the Pd lattice between hydrogen in Pd solid solution and hydrogen in metal hydride, which would influence the effective utilization of active hydrogen atom [H] for dechlorination treatment. An indirect reduction mechanism of the 2,4-D dechlorination on the as-prepared electrodes was also elucidated.
    Applied Catalysis B Environmental 10/2014; s 158–159:38–47. DOI:10.1016/j.apcatb.2014.04.004 · 7.44 Impact Factor
  • Source
    Shams Ali Baig · Qian Wang · Zhuoxing Wang · Jin Zhu · Zimo Lou · Tiantian Sheng · Xinhua Xu
    [Show abstract] [Hide abstract]
    ABSTRACT: In the present study, coupled reduction–sorption of Cr(VI) using three iron containing minerals (magnetite, hematite, and pyrrhotite) in aqueous solutions was investigated as a function of solution pH, contact time, and particle size. Detailed characterizations were performed using Brunauer–Emmett–Teller (BET), environmental scanning electron microscopy, and X-ray diffraction (XRD) techniques. Results demonstrated that over 99% of Cr(VI) removal was achieved just after 1 min of the reaction using pyrrhotite with particle size (100–200 mesh). In comparison, removal efficiency of hematite and magnetite against Cr(VI) was below 40% after 2 h of the reaction. Acidic aqueous medium proved effective for Cr(VI) removal and nearly 100% Cr(VI) removal was achieved at pH 3 using pyrrhotite (30–40 mesh), while the surface efficacy of hematite and magnetite has also improved in acidic solution. In terms of removal efficiency, the three minerals followed the order: pyrrhotite > magnetite > hematite. However, no significant difference in the BET specific surface area was recorded among these minerals, but the mineralogical compositions played an important role for removing Cr(VI) in aqueous solutions. Analysis of XRD pattern revealed that iron contents produce Fe3FeSiO4(OH)5 and FeCr2O4 after the reaction with soluble Cr(VI) and precipitated. This study suggested that high ferrous ions-based minerals can effectively remove Cr(VI) from contaminated water environments.
    CLEAN - Soil Air Water 10/2014; 42(10). DOI:10.1002/clen.201300805 · 1.84 Impact Factor
  • Lisha Tan · Jiang Xu · Xiaoqin Xue · Zhimo Lou · Jin Zhu · Shams Ali Baig · Xinhua Xu
    [Show abstract] [Hide abstract]
    ABSTRACT: Silica-coated magnetite (Fe3O4@SiO2) nanoparticles functionalized with amino, imino and sulfonic groups (Fe3O4@SiO2-mPD/SP) were successfully synthesized via a facile chemical oxidative polymerization of m-phenylenediamine (mPD) and m-sulfophenylenediamine-4-sulfonic acid (SP) monomers, and utilized for selective removal of Pb(II) and Cr(VI) from aqueous solutions. It was revealed by the characterizations that the polymers formed on Fe3O4@SiO2 nanoparticles were the true copolymers with a mPD-SP unit, rather than a mixture of mPD and SP homopolymers. Fe3O4@SiO2-mPD/SP nanocomposites could be easily separated from aqueous solutions within 30 s. The maximum adsorption capacity of Pb(II) (83.23 mg g-1) and Cr(VI) (119.06 mg g-1) on Fe3O4@SiO2-mPD/SP nanocomposites were obtained at the mPD/SP molar ratio of 95:5 and 50:50, respectively. Moreover, satisfactory selective removal of Pb(II) and Cr(VI) from their mixtures with Cu(II) and Ni(II) ions were exhibited by the Fe3O4@SiO2-mPD/SP(95:5) and Fe3O4@SiO2-mPD/SP(50:50), respectively. The Pb(II) adsorption equilibrium was reached within 5 min by Fe3O4@SiO2-mPD/SP(95:5). The adsorption data of Pb(II) and Cr(VI) were both fitted well to the Freundlich isotherm and followed the pseudo-second-order kinetic model. The adsorption mechanism of Pb(II) and Cr(VI) on Fe3O4@SiO2-mPD/SP nanocomposites included five processes, namely: ion-exchange, complexation adsorption, reduction reaction, electrostatic attraction and physical adsorption. The enhanced adsorption performance of nanoparticle-based magnetic adsorbents for selective removal of heavy metal ions can be achieved with such a copolymerization strategy.
    RSC Advances 09/2014; 4(86). DOI:10.1039/C4RA08040H · 3.84 Impact Factor
  • Jie Tang · Yunjun Hu · Shams Ali Baig · Tiantian Sheng · Xinhua Xu
    [Show abstract] [Hide abstract]
    ABSTRACT: The potential of Cr(VI) reduction by Escherichia coli in the presence of soluble Fe(III) was investigated to explore the chemo-biologically mediated reduction process under anaerobic condition. The reduction efficiency of Cr(VI) reached 95% within 24 h. The influences of experimental parameters, including initial pH, temperature, Fe(III) dosage, carbon source, and chelating agent, were also investigated. The highest efficiency of reduction was observed when pH was 5.8 and temperature was 32°C. Amendments of culture medium with Fe(III) and citric-3Na enhanced Cr(VI) reduction, while the addition of EDTA-2Na inhibited the process. Analysis showed that soluble Fe(III) enhanced the reduction process by shuttling electrons from bio-reduced Fe(II) to Cr(VI) in a coupled biotic-abiotic cycle and hence, Cr(VI) was reduced to Cr(III) followed by deposition to sludge.
    Desalination and water treatment 07/2014; 52(22-24). DOI:10.1080/19443994.2013.803325 · 1.17 Impact Factor
  • Source
    Shams Ali Baig · TianTian Sheng · Chen Sun · XiaoQin Xue · LiSha Tan · XinHua Xu
    [Show abstract] [Hide abstract]
    ABSTRACT: The presence of elevated concentration of arsenic in water sources is considered to be health hazard globally. Calcination process is known to change the surface efficacy of the adsorbent. In current study, five adsorbent composites: uncalcined and calcined Fe3O4-HBC prepared at different temperatures (400°C and 1000°C) and environment (air and nitrogen) were investigated for the adsorptive removal of As(V) and As(III) from aqueous solutions determining the influence of solution's pH, contact time, temperature, arsenic concentration and phosphate anions. Characterizations from FTIR, XRD, HT-XRD, BET and SEM analyses revealed that the Fe3O4-HBC composite at higher calcination temperature under nitrogen formed a new product (fayalite, Fe2SiO4) via phase transformation. In aqueous medium, ligand exchange between arsenic and the effective sorbent site ( = FeOOH) was established from the release of hydroxyl group. Langmuir model suggested data of the five adsorbent composites follow the order: Fe3O4-HBC-1000°C(N2)>Fe3O4-HBC (uncalcined)>Fe3O4-HBC-400°C(N2)>Fe3O4-HBC-400°C(air)>Fe3O4-HBC-1000°C(air) and the maximum As(V) and As(III) adsorption capacities were found to be about 3.35 mg g-1 and 3.07 mg g-1, respectively. The adsorption of As(V) and As(III) remained stable in a wider pH range (4-10) using Fe3O4-HBC-1000°C(N2). Additionally, adsorption data fitted well in pseudo-second-order (R2>0.99) rather than pseudo-first-order kinetics model. The adsorption of As(V) and As(III) onto adsorbent composites increase with increase in temperatures indicating that it is an endothermic process. Phosphate concentration (0.0l mM or higher) strongly inhibited As(V) and As(III) removal through the mechanism of competitive adsorption. This study suggests that the selective calcination process could be useful to improve the adsorbent efficiency for enhanced arsenic removal from contaminated water.
    PLoS ONE 06/2014; 9(6):e100704. DOI:10.1371/journal.pone.0100704 · 3.23 Impact Factor
  • Shams Ali Baig · Tiantian Sheng · Yunjun Hu · Jiang Xu · Xinhua Xu
    [Show abstract] [Hide abstract]
    ABSTRACT: Elevated arsenic concentrations have been detected in drinking water sources worldwide and it threatens to over 200 million people in both developing and developed countries. Adsorption is a conventional process for arsenic removal from contaminated water. Several classes of adsorbing materials have been tested so far. However, far less attention was paid towards granular-based adsorption and granulation processes. The present work is the first attempt to consider both the granular adsorbent and the granulation process. A particular emphasis was given to cost-efficient adsorbent for small scale arsenic removal. Some of the features of granular adsorbents are summarized in tables and graphs; address necessary outlines for readers to easily overview the adsorbents' characteristics and design sustainable adsorption system. Earlier, cost of arsenic removals from granular adsorbents were not widely affirmed, but in this review few of them are incorporated for comparisons in future studies. Thus, one gram of arsenic removal from water using novel and iron oxide-coated sand adsorbents is approximately ranged US$2.3–5.1 and US$3.3–4.2, respectively. Moreover, methods employed for regeneration of exhausted granular adsorbents are discussed. Field scale arsenic remediation measures and the performance evaluations are additionally reported to identify the feasibility of these approaches for scaling up, awareness raising and promotion.
    CLEAN - Soil Air Water 05/2014; 43(1). DOI:10.1002/clen.201200466 · 1.84 Impact Factor
  • Source
    Kairan Zhu · Shams Ali Baig · Jiang Xu · Tiantian Sheng · Xinhua Xu
  • Shams Ali Baig
    [Show abstract] [Hide abstract]
    ABSTRACT: Nanosized titanium nitride (nTiN) doped palladium/nickel (Pd/Ni) foam electrodes were successfully prepared via electroless deposition method. The electrodes were evaluated by different techniques including field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and linear sweep voltammetry (LSV). FE-SEM images demonstrated that two different morphologies existed in the Pd layer after nTiN doping. The nTiN doped Pd/Ni foam electrodes were found to be highly effective for electrochemical reductive dechlorination of 2,4-dichlorophenoxyacetic acid (2,4-D) with excellent activity and stability, as revealed by batch experiments. Under the conditions of nTiN doping content of 2 mg, Pd loading of 0.44 mg cm −2 , the energetic electrode achieved nearly 100% removal of 2,4-D (0.226 mmol L −1 ) within 2 h at a current density of 1.667 mA cm −2 . However, the removal efficiency reached only 57.13% when a normal Pd/Ni foam electrode with identical Pd loading and current density was utilized. A successive 2,4-D reductive dechlorination process was observed. o-Chlorophenoxyacetic acid (o-CPA), p-chlorophenoxyacetic acid (p-CPA) and phenoxyacetic acid (PA) were detected and identified as transformation products. Regression analysis proved that the pseudo-first order kinetic model was not suitable to describe the dechlorination process on nTiN doped Pd/Ni foam electrodes due to the appearance of a plateau in the beginning of the curve. Moreover, an adsorption theory for Pd chemisorption of active hydrogen atom was proposed to better explain the phenomenon. An adsorption equilibrium of hydrogen existed in the Pd lattice between hydrogen in Pd solid solution and hydrogen in metal hydride, which would influence the effective utilization of active hydrogen atom [H] for dechlorination treatment. An indirect reduction mechanism of the 2,4-D dechlorination on the as-prepared electrodes was also elucidated.
    Applied Catalysis B: Environmental 04/2014; 158-159:38-47. · 5.63 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Flue gas desulfurization system used for SO2 removal has co-beneficial removal of Hg, which has resulted in Hg-laden gypsums. With growing beneficial reuse applications of the FGD gypsum, it has been recognized as a potential source of Hg pollution. In this paper, the fate and mobility of Hg were investigated. The Hg content in four samples varied widely and it showed a significant correlation between Hg and sulfite contents in gypsum. In leachate, Hg concentration varied during the leaching process. The Hg extraction rate generally increased with decreasing pH value, which suggested that the environmental risk of FGD gypsum increased during the multipurpose utilization processes, resulted from severe acid rain. The released Hg from FGD gypsum used in this study exhibited biphasic kinetics. Hg in FGD gypsum samples not only appeared in the leachate but also re-emitted into the air. The Hg reduction kinetics followed the pseudo-first-order kinetic model well. Our results provide the theoretical understanding for the co-removal of highly soluble oxidized Hg in WFGD systems and also in the recycling of the FGD gypsum.
    Fuel Processing Technology 02/2014; 118:28–33. DOI:10.1016/j.fuproc.2013.08.002 · 3.02 Impact Factor
  • Source
    Tiantian Sheng · Shams Ali Baig · Yunjun Hu · Xiaoqin Xue · Xinhua Xu
    [Show abstract] [Hide abstract]
    ABSTRACT: The adsorptive removal of As(V) from aqueous solutions using iron-coated honeycomb briquette cinder (Fe-HBC) is presented. Low cost mechanical granulation process was integrated with surface amendment technology to prepare iron-oxide modified granular adsorbent for clean water production. Detailed characterizations were performed using FTIR, XRD, EDS and SEM techniques. Operating parameters including initial As(V) concentration, pH, contact time, adsorbent dose, iron leaching and the effects of competing ions on As(V) removal were evaluated. Results demonstrated that high amount of arsenate (961.5 μg g−1) was adsorbed at pH 7.5 in 14 h contact time. Langmuir, Freundlich and Temkin isotherm models were used to analyze the adsorption data, whereas Langmuir model was found to best represent the data with a correlation co-efficient (R2 = 0.999). Thus, As(V) sorption on Fe-HBC surface suggested monolayer adsorption and indicated surface homogeneity. Moreover, the dimensionless parameter (RL) value calculated to be about 0.118 that reiterated the process is favorable and spontaneous. The influences of competing ions on As(V) removal decreased in the following order: PO43->HCO3->F->Cl-. The profound inhibition effects of PO43- revealed a high affinity toward iron(oxy) hydroxide. Life-cycle assessment confirmed that spent HBC is non-hazardous and can be used as a promising sorbent for arsenic removal.
    Arabian Journal of Chemistry 01/2014; 7(1):27–36. DOI:10.1016/j.arabjc.2013.05.032 · 2.68 Impact Factor
  • Shams Ali Baig · Tiantian Sheng · Yunjun Hu · Xiaoshu Lv · Xinhua Xu
    [Show abstract] [Hide abstract]
    ABSTRACT: In this study, adsorptive removal of arsenic in saturated sand filters (SSF(a) and SSF(b)) containing raw and iron-coated honeycomb briquette cinders (HBC and Fe-HBC) is presented. Operating parameters including SSF design, dissolved oxygen (DO), pH, iron leaching and the effects of co-occurring ions on arsenic removal were investigated at 23 ± 2.0 °C temperature for 24-days long treatment. Sampling times (ST) (5-120 min) during treatment days (TD) 1, 6, 12, 18 and 24 were purposively decided to assess filters’ performance from tap water with the spiked of 200 μg/L of As(V) and As(III) into SSF(a) and SSF(b), respectively. No other alteration or pH adjustment was made to the influent water. Results demonstrated that the removal efficiencies of arsenic in SSF(a) and SSF(b) were maintained >95% and >85% till TD-12 and than decreased to 78% and 60%, respectively, on TD-24. Lower arsenic removal in SSF(b) could be the result of As(III) slower oxidation at the studied influent pH under oxic conditions. Decreased in effluent DO and increased iron leaching were measured in both the filters from TD-1 to TD-24. Minor variations of effluents pH and co-occurring ions (Fluoride, Nitrate and Sulphate) were recorded, but no significant effect on arsenic removal was measured in the reported ranges. Performance of NaOH-regenerated filter-beds was evaluated and both filters removed 95% of arsenic in three-cycle treatments. This study suggests of an in situ treatment; by the oxidation of As(III) into As(V) in the presence of DO and hydroxyl radical on adsorbent surfaces, followed by subsequent adsorption through selective physical sorption and Fe-As complexation. SSF containing cost-effective adsorbents could be an effective in situ treatment option to conventional treatment for safe drinking water production.
    Ecological Engineering 11/2013; 60:345-353. DOI:10.1016/j.ecoleng.2013.09.001 · 3.04 Impact Factor
  • Chunsheng Xie · Jiang Xu · Jie Tang · Shams Ali Baig · Xinhua Xu
    [Show abstract] [Hide abstract]
    ABSTRACT: The suppressed ion chromatography (IC) and molybdenum blue methods were used to comparatively evaluate phosphorus (P) concentrations. Most of the P was more resistant to hydrolysis in ion chromatography as compared to the molybdenum blue method. However, P analysis by IC is more liable to be interfered than the molybdenum blue method because of the presence of high bivalent and trivalent metal ions. Polyvalent metal ions interfere with organic P hydrolysis or the release of P from colloids during P investigation, which leads to a difference of ortho-phosphate concentrations determined by IC and molybdenum blue methods. During the environmental samples analysis, the ortho-phosphate obtained by the IC method was usually less than that obtained by the molybdenum blue method.
    Communications in Soil Science and Plant Analysis 09/2013; 44(17). DOI:10.1080/00103624.2013.811518 · 0.42 Impact Factor
  • Source
    Shams Ali Baig
    Ecological Engineering 09/2013; 60:345-353. · 3.04 Impact Factor
  • Jiang Xu · Lisha Tan · Shams Ali Baig · Donglei Wu · Xiaoshu Lv · Xinhua Xu
    [Show abstract] [Hide abstract]
    ABSTRACT: In this study, magnetic Pd/Fe nanoparticles were synthesized using nanoscale Fe3O4 (nFe(3)O(4)) and nanoscale zero-valent iron (nZVI) to significantly enhanced 2,4-DCP dechlorination. nFe(3)O(4) was found to restrain the formation of passivated layer on nZVI surface and promoted the electron transfer. Earlier, only 35.8% 2,4-DCP (C-initial = 20 mg L-1) was removed by 3.0 g L-1 Pd/Fe nanoparticles, whereas it remarkably increased to 76.4% by magnetic nanocomposites (2.0 g L-1 nFe(3)O(4) and 3.0 g L-1 Pd/Fe). A satisfactory long-term stability of nFe(3)O(4)-Pd/Fe was exhibited and the 2,4-DCP removal efficiency reached to 100%, 100%, 93.5%, 93.0%, and 90.1% in five consecutive cycles, respectively. Moreover, the nanocomposites were easily separated from the solution after reaction and that reduced environment related risks of nanoparticles. Weak acidic condition was considered feasible for 2,4-DCP dechlorination. Negative co-precipitation occurred on nFe(3)O(4)-Pd/Fe surface in the presence of common dissolved anions (such as Cl-, PO43-, and HCO3-) and humic acid (HA). The 2,4-DCP dechlorination was notably accelerated by dissolved metallic ions (Fe2+, Cu2+, and Ni2+), and 2,4-DCP was completely removed in 5 h reaction time. The application of nFe(3)O(4)-Pd/Fe nanocomposites could be highly effective for an in situ pollutants remediation measures.
    Chemical Engineering Journal 09/2013; 231:26-35. DOI:10.1016/j.cej.2013.07.018 · 4.32 Impact Factor
  • Shams Ali Baig · Qian Wang · Xiaoshu Lv · Xinhua Xu
    [Show abstract] [Hide abstract]
    ABSTRACT: Cr(VI) is a toxic pollutant and its reduction to relatively less toxic Cr(III) can solve this problem to a greater extent. In the present study, coupled reduction-sorption of Cr(VI) in aqueous solutions using limonite was investigated as a function of pH, limonite dose and particle size. Results demonstrated that the smaller limonite particle size and low pH aqueous medium favored high Cr(VI) removal. Significant Cr(VI) removal (> 55 ± 1%) was achieved with 100-200 mesh, whereas only 25 ± 0.7% and 10 ± 0.5% removals were attained using 30-40 mesh and 20-30 mesh, respectively, after 2 h reaction. Acid pH proved beneficial and the complete Cr(VI) removal was observed at pH < 4.0 compared to that of 10 ± 0.5% at pH 9.0. Moreover, above 53 ± 2.5% of Cr(VI) removal rates were maintained in the first three batch experiment runs and then drastically decreased to below 5 ± 0.3% in experiment Run-7. The Brunauer-Emmett-Teller (BET) surface area and sorption capacity of limonite were 35.22 m2 g− 1 and 10.03 mg g− 1, respectively. The reaction mechanism demonstrated that under acidic aqueous medium, the dissolved Fe(II) and S(II) on limonite surface reacted with Cr(VI) and formed Cr3S4 and Cr5Si3 precipitates. But the resultant precipitates on limonite surface hindered further Cr(VI) removal and passivated, affirmed in XRD and ESEM analyses. This study suggested that limonite can be used for the effective removal of Cr(VI) from contaminated water environments.
    Hydrometallurgy 06/2013; 138:33-39. DOI:10.1016/j.hydromet.2013.05.014 · 2.22 Impact Factor

34 Followers View all