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Comparative study of calcium alginate, ball-milled biochar, and their composites on aqueous methylene blue adsorption
Citation:
Wang, B., B. Gao, AND Y. Wan. Comparative study of calcium alginate, ball-milled biochar, and their composites on aqueous methylene blue adsorption. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH. Ecomed Verlagsgesellschaft AG, Landsberg, Germany, 26:11535-11541, (2019). https://doi.org/10.1007/s11356-018-1497-1
Impact/Purpose:
Environmental and health concerns of wastewater containing methylene blue (MB), a cationic dye heavily used in dyeing and textile industries, challenge scientists and engineers to search for low-cost, eco-friendly adsorbent materials as alternatives of conventional activated carbon, which is expensive for removal of dyes from industrial effluents. In this work, a novel composite, ball-milled biochar (BMB) encapsulated in calcium-alginate (CA) beads (CA-BMB), was synthesized as an alternative adsorbent for removal of methylene blue (MB) from aqueous solution. Sorption performance was compared among CA, BMB, and CA-BMB composite with batch adsorption experiments. It is now demonstrated that nanosized ball-milled biochar can be effectively stabilized in calcium alginate beads to produce a novel adsorbent for removal of methylene blue from aqueous solution. The new composite material contains 25% ball-milled biochar and 75% alginate. The equilibrium adsorption data are well fitted by the Langmuir isotherm, exhibiting a methylene blue adsorption capacity as high as 1210.7 mg g-1. The adsorption kinetics can be best described with Richie’s kinetics model, indicative of energetically heterogeneous solid surface of the composite. The optimal pH ranges from 5 to 11. The new material may serve as a cost-effective, eco-friendly adsorbent for removal of methylene blue from aqueous solution.
Description:
In this work, a novel composite, ball-milled biochar (BMB) encapsulated in calcium-alginate (CA) beads (CA-BMB), was synthesized as an alternative adsorbent for the removal of methylene blue (MB) from an aqueous solution. Sorption performance was compared among CA, BMB, and CA-BMB composite with batch adsorption experiments. With 25% BMB and 75% alginate, the new composite resembled CA in MB adsorption. With an initial MB concentration of 50 mg L−1, kinetics studies showed that 74% MB removal by CA-BMB was achieved within 8 h, followed by slow kinetics reaching 91% removal in 16 h. The adsorption kinetics was well explained by the Ritchie’s kinetic model, indicative of energetically heterogeneous solid surface of the composite. Adsorption isotherms of BMB, CA, and CA-BMB can all be fitted with the Langmuir models; the adsorption capacity of CA-BMB (1210.7 mg g−1) was close to that of CA (1282.2 mg g−1) and much higher than that of BMB alone (184.1 mg g−1). The outstanding adsorption performance suggested that CA-BMB can serve as a low-cost and eco-friendly adsorbent for MB removal from an aqueous solution.
URLs/Downloads:
DOI: Comparative study of calcium alginate, ball-milled biochar, and their composites on aqueous methylene blue adsorption