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Ca^(2+)会强化其对磷酸盐的吸附,而共存Mg^(2+)则会抑制吸附过程.
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 Ca^2+, while it was inhibited in the presence of Mg^2+.
作者
许润
石程好
唐倩
石稳民
康建雄
任拥政
XU Run;SHI Cheng-hao;TANG Qian;SHI Wen-min;KANG Jian-xiong;REN Yong-zheng(School of Environmental Science & Engineering, Huazhong University of Science and Technology,Wuhan 430074,China;China Construction Third Bureau Green Industry Investment Co.,Ltd.,Wuhan 430056, China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2019年第4期1834-1841,共8页
Environmental Science
基金
国家重点研发计划项目(2016YFC0400703)
关键词
除磷
吸附
稻壳生物炭
氢氧化镧
介孔
phosphate removal
adsorption
rice husk biochar
lanthanum hydroxide
mesoporosity
