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Enhanced arsenic removal by biochar modified with nickel (Ni) and manganese (Mn) oxyhydroxides
Shengsen Wang,Bin Gao,Yuncong Li 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.37 No.-
Two biochar composites were synthesized by either pyrolysis of Ni/Mn oxide-modified pinewoodfeedstock (NMMF) or precipitation of Ni/Mn-LDHs onto pristine biochars (NMMB). Both sorbents werecharacterized and results indicated that NiO and MnO were dominant crystals in NMMF, whereas Ni/Mn-LDHs in NMMB. Sorption experiment showed that the maximum As(V) sorption capacity were 0.549 and6.52 g kg 1 for NMMF and NMMB, respectively. The As(V)-loaded sorbents can be easily desorbed with0.1 NaOH, and NMMB maintained 98% removal efficiency after two to three desorption–resorptioncycles. The As(V) sorption is mainly attributed to anion exchange and surface complexation by NMMBand surface complexation by NMMF.
Biochar-supported nZVI (nZVI/BC) for contaminant removal from soil and water: A critical review
Wang, Shengsen,Zhao, Mingyue,Zhou, Min,Li, Yuncong C.,Wang, Jun,Gao, Bin,Sato, Shinjiro,Feng, Ke,Yin, Weiqin,Igalavithana, Avanthi Deshani,Oleszczuk, Patryk,Wang, Xiaozhi,Ok, Yong Sik Elsevier 2019 Journal of hazardous materials Vol.373 No.-
<P><B>Abstract</B></P> <P>The promising characteristics of nanoscale zero-valent iron (nZVI) have not been fully exploited owing to intrinsic limitations. Carbon-enriched biochar (BC) has been widely used to overcome the limitations of nZVI and improve its reaction with environmental pollutants. This work reviews the preparation of nZVI/BC nanocomposites; the effects of BC as a supporting matrix on the nZVI crystallite size, dispersion, and oxidation and electron transfer capacity; and its interaction mechanisms with contaminants. The literature review suggests that the properties and preparation conditions of BC (e.g., pore structure, functional groups, feedstock composition, and pyrogenic temperature) play important roles in the manipulation of nZVI properties. This review discusses the interactions of nZVI/BC composites with heavy metals, nitrates, and organic compounds in soil and water. Overall, BC contributes to the removal of contaminants because it can attenuate contaminants on the surface of nZVI/BC; it also enhances electron transfer from nZVI to target contaminants owing to its good electrical conductivity and improves the crystallite size and dispersion of nZVI. This review is intended to provide insights into methods of optimizing nZVI/BC synthesis and maximizing the efficiency of nZVI in environmental cleanup.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Aggregation and passivation of nZVI can be alleviated by surfactants and doping methods. </LI> <LI> BC hinders corrosion and improves the dispersion and electron transfer of nZVI. </LI> <LI> Properties of nZVI depend on those of the BC, feedstock and pyrogenic temperature. </LI> <LI> BC enhances electron transfer from nZVI to the contaminants due to the presence of quinone and graphene moieties. </LI> <LI> nZVI/BC shows strong ability to remove HMs, nitrates, and organic contaminants in soil and water. </LI> </UL> </P>
Stefan Wan,Shengsen Wang,Yuncong Li,Bin Gao 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.47 No.-
This study examined phosphate adsorption of bamboo biochar functionalized with varying amount ofMg–Al and Mg–Fe (3:1) layered double hydroxides (LDH). Results indicated that the compositecontaining 40% Mg–Al LDH exhibited the highest phosphate adsorption with >95% phosphate saturationachieved within 1 h, following the pseudo-second-order kinetics model. Characterization and adsorptionisotherm of this composite revealed interlayer anion exchange and surface adsorption as thepredominant adsorption mechanism at low phosphate concentrations and phosphate precipitation athigh concentrations. A lettuce seedling bioassay further demonstrated that the spent LDH/biocharcomposite can be recycled as a slow-release fertilizer to enhance food production.
Zhuhong Ding,Zhuhong Ding,Yongshan Wan,Shengsen Wang,Bin Gao 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.33 No.-
Engineered biochar was obtained through slow pyrolysis of hickory wood and then further modifiedwith NaOH. After modification, biochar’s surface area, cation-exchange capacity, and thermal stabilitywere significantly improved. The modified biochar exhibited much larger (2.6–5.8 times) metaladsorption capacities than the pristine biochar. Competitive batch adsorption of mixed metal ions (Pb2+,Cd2+, Cu2+, Zn2+, and Ni2+) showed preferential adsorption of Pb2+ and Cu2+ onto the modified biochar. The alkali-modified biochar in a fixed-bed column also showed strong ability to filter heavy metals fromaqueous solutions. The alkali-modified biochar thus can serve as alternative absorbent for heavy metals
Zhuhong Ding,Bin Gao,Yongshang Wan,Xinhua Zhu,Shengsen Wang,Andrew R. Zimmerman 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.37 No.-
Hickory biochars were obtained through slow pyrolysis under 350 8C, 450 8C, and 600 8C. Multiplecharacterization techniques were used to characterize the biochars and showed pyrolysis temperatureaffected their O/C ratios, surface areas, cation-exchange capacities, zeta potential, surface acidic groups. As the result, the biochars showed different adsorption ability to Pb(II) and methylene blue in aqueoussolutions, which was due to the important roles of the physicochemical properties of the biochars incontrolling the sorption processes. This work provided a comprehensive evaluation of biochars, and thusexpanded on previous research on effects of pyrolysis temperature on biochar properties.