中文关键词一硫代砷(MTA)针铁矿胡敏酸(HA)吸附作用影响因素 英文关键词monothioarsenate (MTA)goethitehumic acid (HA)adsorptioninfluencing factors

作者	单位	E-mail
廖丹雪	桂林理工大学广西环境污染控制理论与技术重点实验室, 桂林 541004 桂林理工大学岩溶地区水污染控制与用水安全保障协同创新中心, 桂林 541004	liaodanxue5@163.com
单慧媚	桂林理工大学广西环境污染控制理论与技术重点实验室, 桂林 541004 桂林理工大学岩溶地区水污染控制与用水安全保障协同创新中心, 桂林 541004	shanhuimei@glut.edu.cn
张进贤	桂林理工大学广西环境污染控制理论与技术重点实验室, 桂林 541004 桂林理工大学岩溶地区水污染控制与用水安全保障协同创新中心, 桂林 541004
彭三曦	桂林理工大学地球科学学院, 桂林 541004
黄健	桂林理工大学广西环境污染控制理论与技术重点实验室, 桂林 541004 桂林理工大学岩溶地区水污染控制与用水安全保障协同创新中心, 桂林 541004
陈辉	桂林理工大学广西环境污染控制理论与技术重点实验室, 桂林 541004 桂林理工大学岩溶地区水污染控制与用水安全保障协同创新中心, 桂林 541004
赵超然	桂林理工大学广西环境污染控制理论与技术重点实验室, 桂林 541004 桂林理工大学岩溶地区水污染控制与用水安全保障协同创新中心, 桂林 541004
曾春芽	桂林理工大学广西环境污染控制理论与技术重点实验室, 桂林 541004 桂林理工大学岩溶地区水污染控制与用水安全保障协同创新中心, 桂林 541004

中文摘要 以一硫代砷酸盐（monothioarsenate，MTA）为研究对象，查明其在针铁矿上的吸附特征，分析砷酸盐、亚砷酸盐、胡敏酸（humic acid，HA）、硝酸盐和磷酸盐对针铁矿吸附MTA的影响并识别作用机制.结果发现：①当溶液中仅有一种砷形态时，MTA、砷酸盐和亚砷酸盐在针铁矿上的吸附平衡时间分别为8、2和4 h，吸附过程均符合假二级动力学模型，平衡吸附量（q_e）分别为2129.851、3291.838和1788.767 mg·kg^-1；当溶液中两种砷形态（砷酸盐与MTA，或亚砷酸盐与MTA）共存时，MTA在针铁矿上的吸附过程仍符合假二级动力学模型，但q_e显著减少，分别为1236.941 mg·kg^-1和1532.287 mg·kg^-1，主要原因是砷酸盐和亚砷酸盐均能与MTA竞争吸附位点.② MTA在针铁矿上的q_e随着HA浓度（10~50 mg·L^-1）的增加而逐渐降低，因为HA大量的官能团抢占了针铁矿表面吸附点位，从而抑制了MTA的吸附；③当溶液中添加磷酸盐时，MTA、砷酸盐和亚砷酸盐在针铁矿上的q_e显著降低，分别为492.802、815.782和303.714 mg·kg^-1，这是因为P与As存在竞争性吸附；当添加硝酸盐时，溶液中电子受体数量和Eh增加从而使得3种砷形态的q_e均增大，分别为2211.030、3444.023和1835.537 mg·kg^-1. 英文摘要 The adsorption kinetic of monothioarsenate (MTA) on goethite was characterized in this study, and batch experiments were then designed to further explore the effects of arsenate, arsenite, humic acid (HA), nitrate, and phosphate on the adsorption of MTA on goethite, and to identify the adsorption mechanism. The results showed that:① When a single arsenic species was present in a solution, the adsorption equilibrium times of MTA, arsenate, and arsenite on goethite were 8, 2, and 4 h, respectively. The adsorption experimental data of these three arsenic species were well fitted to a pseudo-second-order kinetic model. The equilibrium adsorption capacities (q_e) of MTA, arsenate, and arsenite on goethite were 2129.851, 3291.838, and 1788.767 mg·kg^-1, respectively. When MTA coexisted with arsenate or arsenite in a solution, MTA adsorption on goethite continued to be well fitted to a pseudo-second-order kinetic model. The value of q_e for MTA was significantly reduced to 1236.941 mg·kg^-1 when MTA coexisted with arsenate, and to 1532.287 mg·kg^-1 when MTA coexisted with arsenite, due to the fact that arsenate and arsenite competed for adsorption sites with MTA. ② With an increase in HA concentration (10-50 mg·L^-1), the q_e of MTA decreased gradually, due to the fact that a large number of functional groups in HA preempted the surface adsorption sites of goethite with MTA. ③ When phosphate was added into the MTA solution, the q_e values of MTA, arsenate, and arsenite on goethite were reduced greatly, to 492.802, 815.782, and 303.714 mg·kg^-1, respectively, which was caused by the competitive adsorption of P and As. When nitrate was added into the MTA solution, the number of electron receptors and Eh of the solution increased, leading to the q_e values of MTA, arsenate, and arsenite on goethite increasing to 2211.030, 3444.023, and 1835.537 mg·kg^-1, respectively.

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