铁改性污泥生物炭对水中Cr(VI)的吸附性能研究

Study on adsorption properties of iron-modified sludge biochar for Cr(VI)in water

通过剩余污泥热解、活化、铁改性,制备了铁改性污泥生物炭(Fe-S@HKBC),采用扫描电镜(SEM)、X-射线衍射(XRD)、傅里叶红外光谱(FT-IR)、比表面及孔隙度分析仪(BET)等对其进行了表征分析;考察了生物炭用量、Cr(VI)初始浓度、溶液pH、共存离子(Na^(+)、Ca^(2+))等对Fe-S@HKBC吸附去除水中Cr(VI)的影响,并探讨了吸附机理.结果表明,Fe-S@HKBC的比表面积为283.96 m^(2)/g,其表面富含Fe-O、C-O、-C=O、-OH等官能团.在生物炭用量为4 g/L,Cr(VI)初始浓度为10~300 mg/L时,Fe-S@HKBC对Cr(VI)的吸附量可达47.69 mg/g,去除率高达99.82%,均明显高于BC.Langmuir吸附等温线和伪二级动力学模型均能够较好描述吸附过程.Fe-S@HKBC吸附Cr(VI)的主要作用机制包括氢键、络合、还原和静电引力作用.研究结果为Cr(VI)的有效去除和污泥的处置提供了理论依据.

Iron modified sludge biochar(Fe-S@HKBC)was prepared by excess sludge via pyrolysis,activation,and iron modification.The properties of Fe-S@HKBC were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),and Specific surface and porosity analysis(BET);The effects of the biochar dosage,initial Cr(VI)concentration,solution pH and coexisting cations(Na^(+),Ca^(2+))on Cr(VI)removal by Fe-S@HKBC were studied.The adsorption mechanism was also discussed.Results showed that the specific surface area of Fe-S@HKBC was 283.96 m^(2)/g.The surface of Fe-S@HKBC contained rich functional groups such as Fe-O,C-O,-C=O,-OH,etc.Under Fe-S@HKBC dosage of 4 g/L and initial Cr(VI)concentration of 10~300 mg/L,the adsorption amount and removal rate of Fe-S@HKBC for Cr(VI)reached 47.69 mg/g and 99.82%,respectively,both obviously higher than BC.Langmuir isotherm and pseudo-second-order kinetic model could well described the adsorption process.The adsorption mechanism includes hydrogen bond,complexation,reduction,and electrostatic attraction.This study provided useful insights into Cr(VI)effective removal and sludge disposal.