Graphene Oxide Nanocomposite Hydrogel Beads for Removal of Selenium in Contaminated Water
Graphene Oxide Nanocomposite Hydrogel Beads for Removal of Selenium in Contaminated Water
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DOI：
10.1021/acsapm.9b00612
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发表时间：
2019-10-01
影响因子：
5
通讯作者：
Rodrigues, Debora Frigi
中科院分区：
文献类型：
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作者：
Bandara, Pasan Chinthana;Perez, Jem Valerie D.;Rodrigues, Debora Frigi
水中的硒对人类暴露的风险越来越大，因为直到最近才发现水资源中存在严重的健康影响。本研究采用响应面法研究了氧化石墨烯聚合物纳米复合水凝胶珠的组成和优化。使用富含胺和醇官能团的聚合物如壳聚糖和聚乙烯亚胺，提供了增强的阴离子硒物质从水中的去除。实验验证的聚合物珠被用来进行批量吸附硒在不同的条件下，如pH值，珠剂量，和不同的硒浓度，以研究其潜在的用途，吸附动力学，和硒去除机制。发现酸性条件通过珠粒中存在的-OH、-COOH和胺官能团从水溶液中最好地去除带负电荷的硒离子。吸附动力学机制更好地描述了伪二级吸附动力学，表明珠通过化学吸附机理去除硒。等温线研究表明，基于25 ℃下的朗缪尔等温线，吸附容量为1.62 mg/g。再生研究表明，可用的吸附位点的损失后，用不同浓度的NaOH和HCl的第一次解吸处理。数学优化的纳米复合材料进一步用于处理加标在真实的环境水样中的硒，这证实了在酸性条件下发生的最佳硒去除。
Selenium in water is becoming of increasing risk to human exposure because only recently serious health effects have been associated with their presence in water resources. The present study investigated the development and optimization of the composition of graphene oxide polymeric nanocomposite hydrogel beads by using response surface methodology. The use of polymers such as chitosan and polyethylenimine, which are rich in amine and alcoholic functional groups, provided enhanced removal of anionic selenium species from the water. Experimentally validated polymeric beads were used to perform batch adsorptions of selenium under different conditions such as pH, bead dosage, and diverse selenium concentrations to investigate their potential use, adsorption kinetics, and selenium removal mechanisms. Acidic conditions were found to best remove negatively charged selenium ions from aqueous solutions via -OH, -COOH, and amine functional groups present in the beads. The adsorption kinetic mechanism was better described by the pseudo-second-order adsorption kinetics, indicating that the beads remove selenium via chemisorption mechanisms. The isotherm studies showed an adsorption capacity of 1.62 mg/g based on the Langmuir isotherms at 25 degrees C. Regeneration studies showed loss of available adsorption sites after the first desorption treatment with different concentrations of NaOH and HCl. The mathematically optimized nanocomposite was further used to treat selenium spiked in real environmental water samples, which confirmed that the best removal of selenium occurs in acidic conditions.