熔盐法制生物炭用于吸附酸性工业废水中的Pb^(2+)

Biochar Prepared by Molten Salt Method and Its Application to Adsorption of Pb^(2+)in Acidic Industrial Wastewater

作者设计了一种含有表面衍生官能团的生物质材料,用于吸附印染、脱硫等废水中的可溶性铅污染。在500℃热解下,采用熔盐法制备生物炭材料,其产率接近40%,具备介孔/大孔杂化特性,比表面积接近300 m^(2)/g。通过高锰酸钾改性,发现其对Pb^(2+)的最大吸附量可以达到商业活性炭的8倍。研究初始pH、吸附时间、污染物浓度等因素对生物炭吸附Pb^(2+)的影响,发现生物炭对Pb^(2+)的吸附倾向遵循准二级动力学模型和Langmuir等温吸附模型。结合生物炭吸附剂使用前后的材料表征,阐述了包括静电作用、π-π作用、离子交换和络合作用在内的吸附机制。研究结果还表明生物炭BC-B在酸性条件下可以快速有效地吸附Pb^(2+),在生物炭投加量=0.5 g/L、[Pb^(2+)]=400 mg/L、pH=7的条件下对Pb^(2+)的最大吸附量达到440.0 mg/g。同时循环再生实验和工业废水应用实验证明,该生物炭在治理含重金属的酸性工业废水中具有潜力。

Laboratory experimental studies were carried out for the purpose of developing a kind of biomass material containing surface-derived functional groups,which was used to adsorb soluble lead pollutants in wastewater such as printing,dyeing and desulfurization industrial effluents.In this way,biochar as a sort of biomass material was prepared at the laboratory by molten salt method at 500℃,the production rate being about 40%,and biochar thus prepared had hybrid mesoporous/microporous structure with the surface area of ca 300 m^(2)/g.Then the biochar was modified in potassium permanganate solution,which showed an excellent capacity of Pb^(2+)adsorption,with eight times stronger than that of common commercially available activated carbon.In addition,the effects of initial pH,adsorption time and pollutant concentration of the wastewater on the adsorption of Pb^(2+)onto biochar were investigated.The experiment proved that the behavior adsorption of Pb^(2+)onto biochar matched well with the pseudo-second-order kinetic model and the Langmuir isotherm adsorption model,and following the characterization of biochar before and after the Pb^(2+)adsorption,the paper elucidated the adsorption mechanism regarding the electrostatic interaction,π-πinteraction,ion exchange and complexation functions,and reported that biochar BC-B had the quick and effective adsorption capacity and could maximized the adsorption amount up to 440.0 mg/g under an optimal condition:biochar dosage of 0.5 g/L,[Pb^(2+)]=400 mg/L and pH=7.Simultaneously,the reuse experiments and practical application experiments demonstrated that the biomass-derived biochar was of potentiality in the industrial wastewater treatment for removing heavy metal.