Enhanced nitrate removal by novel bimetallic Fe/Ni nanoparticles supported on biochar
Enhanced nitrate removal by novel bimetallic Fe/Ni nanoparticles supported on biochar
复制标题
DOI：
10.1016/j.jclepro.2017.03.042
复制
发表时间：
2017-05-10
影响因子：
11.1
通讯作者：
Wang, Kangming
中科院分区：
文献类型：
--
作者：
Li, Pengjun;Lin, Kairong;Wang, Kangming
在这项研究中，建立了一种负载在生物炭上的新型双金属铁/镍纳米颗粒（BC@Fe/Ni）来降解水中的硝酸盐污染。该纳米复合材料由钢铁酸洗废液和甘蔗渣制备而成，成本低廉。纳米复合材料的粒径范围为10 nm~20 nm左右,比表面积(59.83 m(2)/g)比钢铁酸洗废液制备的纳米零价铁(S-NZVI)大约71%,证明生物炭对铁镍双金属颗粒具有良好的分散效果。在不控制 pH 值的情况下，硝酸盐浓度低于 50 mg/L 时，可实现超过 93% 的高硝酸盐去除率。批量实验结果表明，动力学曲线符合准一级反应。研究还发现，较高的纳米复合材料用量、较低的初始硝酸盐浓度和酸性介质有利于硝酸盐的降解。此外，由于生物炭的存在，观察到4 g/L负载在生物炭上的双金属铁/镍纳米粒子的硝酸盐（20 mg/L）降解速率的准一级速率系数比2 g/L双金属铁/镍纳米颗粒的降解速率快30%。由于生物炭和纳米零价镍催化剂的同时存在，比2 g/L纳米零价铁快75%。此外，由于生物炭的吸附作用，铁和镍离子污染发生在双金属铁/镍纳米粒子的反硝化系统中，而在生物炭负载的双金属铁/镍纳米粒子的反硝化系统中则没有。生物炭负载的铁/镍双金属纳米颗粒反硝化后，大部分硝酸盐转化为氨（17.04 mg/L），仅有少量亚硝酸盐（0.024 mg/L），硝酸盐去除率较高（99.5%）。大部分氨可以被阳离子交换树脂吸收，最终氨浓度为0.58 mg/L。最后，纳米复合材料体系中硝酸盐（0.24 mg/L）、亚硝酸盐（0.021 mg/L）和总氮（0.84 mg/L）的浓度最低。总体而言，生物炭负载的双金属铁/镍纳米颗粒在与阳离子交换树脂结合使用时，在高效降解硝酸盐、防止铁镍污染、去除氨污染方面比双金属铁/镍纳米颗粒和纳米零价铁表现出明显的优势。 (C) 2017 Elsevier Ltd. 保留所有权利。
In this study, a novel bimetallic iron/nickel nanoparticles supported on biochar (BC@Fe/Ni) was established to degrade nitrate pollution in water. The nanocomposite was prepared from steel pickling waste liquor and sugarcane bagasse, which are made at low cost. The particle sizes of the nanocomposite ranged from about 10 nm to 20 nm and its specific surface area (59.83 m(2)/g) was about 71% bigger than that of nanoscale zero valent iron prepared from steel pickling waste liquor (S-NZVI), which proved that biochar had an excellent dispersal effect on bimetallic iron/nickel particles. Without controlling the pH, high nitrate removal rates over 93% could be realized in nitrate concentrations below 50 mg/L. The results of batch experiments demonstrated that the kinetics curves fitted the pseudo-first-order reaction well. And it was also found that higher dosages of the nanocomposite, lower initial nitrate concentrations, and acid medium facilitated nitrate degradation. In addition, the observed pseudo-first order rate coefficient in nitrate (20 mg/L) degradation rate by 4 g/L of the bimetallic iron/nickel supported on biochar was 30% faster than that by 2 g/L the bimetallic iron/nickel nanoparticles, due to the existence of biochar. And it was 75% faster than that by 2 g/L the nanoscale zero valent iron due to the existence of both biochar and the nanoscale zero valent nickel catalyst. Furthermore, iron and nickel ion pollution occurred in the denitrification system with bimetallic iron/nickel nanoparticles but not in that with the bimetallic iron/nickel nanoparticles supported on biochar, due to the biochar's adsorption. After denitrification by the bimetallic iron/nickel nanoparticles supported on biochar, most of nitrate turned into ammonia (17.04 mg/L) and there only was a small amount of nitrite (0.024 mg/L) with high nitrate removal rate (99.5%). And most of ammonia can be absorbed by cation exchange resin with finial ammonia concentration of 0.58 mg/L. At last, the concentrations of nitrate (0.24 mg/L), nitrite (0.021 mg/ L), and total nitrogen (0.84 mg/L) were lowest in the nanocomposite system. Overall, the bimetallic iron/ nickel nanoparticles supported on biochar exhibited clear advantages over bimetallic iron/nickel nano particles and nanoscale zero valent iron with respect to degrading nitrate efficiently, preventing iron and nickel pollution and removing ammonia pollution in combination with cation exchange resin. (C) 2017 Elsevier Ltd. All rights reserved.