摘要
为改善稻壳炭对Cd^(2+)的吸附能力,分别选用壳聚糖、硝酸铁与高锰酸钾对稻壳生物炭进行改性,成功制备了壳聚糖改性稻壳炭(C-BC)和铁锰改性稻壳炭(FM-BC),表征了各稻壳炭的基础理化性质,包括比表面积分析(BET)、傅里叶变换红外光谱(FTIR)、X射线衍射表征(XRD),进行了动力学吸附实验和等温吸附实验,并在不同pH和投加量条件下,研究了改性生物炭对Cd^(2+)的吸附量和去除率。结果表明:两种改性方式均减小了稻壳炭的比表面积和总孔隙体积;FM-BC含有Mn-O、Fe-O的特征官能团,此外改性前后稻壳炭的官能团类型基本不变;两种改性方式均使稻壳炭产生了对应的晶体结构变化。两种改性炭对Cd^(2+)动力学吸附特征均符合准二级动力学模型,颗粒内扩散模型均分为3个阶段,对Cd^(2+)等温吸附特征均符合Langmuir模型;C-BC和FM-BC的最大吸附量分别为25.51 mg·g^(-1)和16.25 mg·g^(-1),是BC(14.97 mg·g^(-1))的1.7倍和1.08倍。随着溶液pH增加,C-BC和FMBC的吸附量和去除率逐渐增加,且始终高于BC;随着投加量的增加,C-BC和FM-BC的Cd^(2+)去除率逐渐增加,而吸附量逐渐降低。两种改性方式均能够在一定程度上提高稻壳炭对Cd^(2+)的吸附能力,均以单分子层化学吸附占主导,C-BC的最大吸附量明显高于FM-BC,适度调整溶液pH和投加量可改善改性稻壳炭的Cd^(2+)吸附效果。
To improve the Cd^(2+)adsorption capacity of rice husk charcoal.Chitosan,iron nitrate,and potassium permanganate were used to modify rice husk biochar.Chitosan-modified rice husk biochar(C-BC)and iron-manganese-modified rice husk biochar(FM-BC)were prepared,and the basic physical and chemical properties of each rice husk biochar were characterized via specific surface area analysis,Fourier transform infrared spectroscopy,and X-ray diffraction characterization.Subsequently,kinetic adsorption and isothermal adsorption experiments were conducted,and the adsorption amount and removal rate of Cd^(2+)by modified biochar were investigated under different pH and dosing conditions.The results showed that both modification methods reduced the specific surface area and total pore volume of rice husk carbon.FM-BC was found to contain the characteristic functional groups Mn-O and Fe-O.In addition,the functional group types of rice husk charcoal before and after modification were found to have remained unchanged.Both modification methods induced corresponding crystal structure changes in rice husk carbon.The kinetic adsorption characteristics of Cd^(2+)on the two modified carbons were in accordance with the pseudo-second-order kinetic model.The intra-particle diffusion model was divided into three stages,and the isothermal adsorption characteristics of Cd^(2+)were found to be in accordance with the Langmuir model.The equilibrium adsorption capacities of C-BC and FM-BC were 25.51 mg·g^(-1)and 16.25 mg·g^(-1),respectively,which were 1.7 times and 1.08 times that of BC(14.97 mg·g^(-1)).Finally,with the increase of solution pH,the adsorption capacity and removal rate of C-BC and FM-BC gradually increased,and were always higher than those of BC.With increasing dosage,the Cd^(2+)removal rate of C-BC and FM-BC increased gradually,while the adsorption capacity decreased gradually.Both modifications can improve the Cd^(2+)adsorption capacity of rice husk carbon to some extent,and both are dominated by single-molecule layer chemisorp
作者
王江南
孙晓雪
杨玲辉
姜楠
张淼
刘遵奇
赫天一
WANG Jiangnan;SUN Xiaoxue;YANG Linghui;JIANG Nan;ZHANG Miao;LIU Zunqi;HE Tianyi(College of Agronomy,Shenyang Agricultural University/National Biochar Research Institute/Key Laboratory of Biochar and Soil Improvement,Ministry of Agriculture and Rural Affairs,Shenyang 110866,China;Shenyang Rural Revitalization and Development Center,Shenyang 110034,China)
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2023年第9期1964-1973,共10页
Journal of Agro-Environment Science
基金
辽宁省科技计划面上项目(2021-MS-232)
国家自然科学基金青年科学基金项目(31901449)
中央引导地方发展资金项目(2023030318-JH6/1001)。
