玉米秸秆生物炭的制备改性及其对孔雀石绿染料的吸附效果

Preparation and modification of corn straw biochar and its adsorption effect on malachite green dye

利用玉米秸秆制备了生物炭并对其进行了改性,将其用于处理废水中的有机染料孔雀石绿。采用SEM、XRD、FTIR、N_(2)吸附-脱附等方法对生物炭的形貌及结构进行了表征,研究了影响吸附效果的因素及吸附过程的特点,并通过吸附动力学、吸附等温线和吸附热力学研究了生物炭对孔雀石绿的吸附规律。实验结果表明,原炭(CSC)、NaOH改性生物炭(NaCSC)和十六烷基三甲基溴化铵进一步改性的NaCSC(CTAB-NaCSC)对孔雀石绿的吸附效果良好,吸附过程符合准二级动力学模型,相关系数分别为0.9976,0.9920,0.9799。与CSC比,NaCSC的表面粗糙程度增加,孔径增大,孔隙分布不规则,提高了对孔雀石绿的吸附能力;CTAB-NaCSC的表面更加粗糙不平,且有颗粒状凸起。CSC,NaCSC,CTAB-NaCSC的吸附-脱附循环再生实验结果表明,三种生物炭具有良好的循环利用性,再生率分别达到84.29%,91.59%,111.75%。

The biochar was prepared from corn straw and modified for treatment of organic dye malachite green in wastewater.The morphology and structure of the biochar were characterized by SEM,XRD,FTIR,N_(2)adsorption-desorption.The factors affecting the adsorption and the characteristics of adsorption process were studied.The adsorption regularities of biochar to malachite green were studied through adsorption kinetics,adsorption isotherms and adsorption thermodynamics.The experimental results show that malachite green has good adsorption effect on the raw biochar(CSC),NaOH-modified biochar(NaCSC)and NaCSC further-modified with hexadecyl trimethyl ammonium bromide(CTAB-NaCSC).Their adsorption processes follow the quasi second-order kinetic model with the correlation coefficient of 0.9976(CSC),0.9920(NaCSC),0.9799(CTAB-NaCSC),respectively.Compared with CSC,NaCSC has rougher surface,larger pore size and irregular pore distribution,which improve its adsorption capacity for malachite green.The surface of CTAB-NaCSC is rougher and has granular protrusions.CSC,NaCSC and CTAB-NaCSC have good recyclability,and the regeneration rate reach 84.29%,91.59%,111.75%,respectively.