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氢氧化镧改性介孔稻壳生物炭除磷性能

本站小编 Free考研考试/2021-12-31

中文关键词除磷吸附稻壳生物炭氢氧化镧介孔 英文关键词phosphate removaladsorptionrice husk biocharlanthanum hydroxidemesoporosity
作者单位E-mail
许润华中科技大学环境科学与工程学院, 武汉 430074hgzxxr608@163.com
石程好华中科技大学环境科学与工程学院, 武汉 430074
唐倩华中科技大学环境科学与工程学院, 武汉 430074
石稳民中建三局绿色产业投资有限公司, 武汉 430056
康建雄华中科技大学环境科学与工程学院, 武汉 430074
任拥政华中科技大学环境科学与工程学院, 武汉 430074renyz@163.com
中文摘要 通过共沉淀法将氢氧化镧固定在高介孔率的稻壳生物炭上,重点研究了生物炭孔结构、溶液pH和共存物质对氢氧化镧改性介孔稻壳生物炭吸附磷酸盐的影响.结果表明,镧负载量与生物炭介孔率呈正相关,生物炭介孔率越高,对磷酸盐的吸附速率越快,镧浸出量越低.吸附过程符合伪二级动力学模型,且受颗粒内扩散控制.Langmuir模型能够较好地描述氢氧化镧改性介孔稻壳生物炭对磷酸盐的吸附过程,理论最大吸附量分别为41.22、43.26和45.62 mg·g-1,镧利用率较高,P/La量比均大于1.5.此外,氢氧化镧改性介孔稻壳生物炭能在pH 3~9的范围内有效吸附磷酸盐.共存物质影响实验表明,氢氧化镧改性介孔稻壳生物炭对磷酸盐表现出良好的选择吸附性,共存Ca2+会强化其对磷酸盐的吸附,而共存Mg2+则会抑制吸附过程. 英文摘要 La-modified RHBCs (La-RHBCs) were fabricated by immobilizing La(OH)3 nanoparticles on mesoporous rice husk biochars (RHBCs) using a co-precipitation method. Specifically, the effects of the pore structure of the RHBCs, solution pH, and coexisting substances on phosphate adsorption by the La-RHBCs were studied. The results showed that the La loading of the La-RHBCs was positively correlated with the mesoporosity of the RHBCs. La-modified RHBCs with higher mesoporosity hosts showed faster adsorption rates and lower leaching of La during phosphate adsorption. The adsorption process could be described by a pseudo second-order kinetic model, and the reaction rate was controlled by intraparticle diffusion. The Langmuir isotherm model fitted the adsorption process better, and the theoretical maximum adsorption capacities were 41.22, 43.26, and 45.62 mg·g-1, respectively. The high P/La molar ratios of more than 1.5 indicated the high utilization efficiencies of the La in the La-immobilized RHBCs. Moreover, phosphate could be effectively removed by the La-modified RHBCs over a wide pH range of 3-9. The La-modified RHBCs also exhibited good adsorption selectivity towards phosphate in the presence of coexisting anions and humic acids. Phosphate adsorption by the La-RHBCs was enhanced in the presence of Ca2+, while it was inhibited in the presence of Mg2+.

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