改性玉米秸秆生物炭对化粪池出水中氨氮的吸附

Adsorption of Ammonium in Septic Tank Effluent by Modified Corn Stalk Biochar

生物炭是通过生物材料热解制备的富含炭的固体产品。实验以玉米秸秆生物炭为原料,在使用碱溶液进行预处理后,用KMnO_(4)、H_(2)O_(2)和HNO_(3)分别改性,得到三种不同的改性生物炭。通过SEM、FTIR和XPS等材料学方法表征后发现改性后的生物炭表面出现明显的孔穴结构且比表面积明显增加。此外,改性后的生物炭具有更丰富的表面官能团和更多的不饱和键,氨氮以NH4+形式与表面官能团结合。吸附性能实验显示,改性后的生物炭可在短时间内达到吸附平衡,最大平衡吸附量可达23.80 mg/g,吸附能力明显提升。将改性生物炭应用于粪污分离液的结果表明,改性玉米秸秆生物炭可以有效去除其中的氨氮,最大去除率可达50.6%。本研究为开展农业废弃物的回收与资源化利用提供了理论支撑。

Biochar is a carbon-riched product prepared by the pyrolysis of biomaterials.Three kinds of modified biochars(KMnO_(4)-CC,H_(2)O_(2)-CC,and HNO_(3)-CC)from cornstalk were obtained by pretreated with an alkali solution and modified with different solutions,e.g.,potassium permanganate,hydrogen peroxide,and nitric acid.It was found that the surface of modified biochars had a pore structure and higher specific surface area by analyzing SEM,FTIR,and XPS.In addition,the modified biochars had more abundant surface functional groups and unsaturated bonds,and ammonia nitrogen is bound to the surface functional groups in the form of NH4+.The adsorption experiment showed that the modified biochars could reach equilibrium in a short time,the maximum equilibrium adsorption capacity could reach 23.80 mg/g,and the adsorption capacity was significantly improved.The experiment of septic tank effluent revealed that modified biochars can effectively remove ammonium in the septic tank effluent,and the maximum removal rate can reach 50.6%,which provides theoretical support for the recovery and resource utilization of agricultural waste.