Groundwater contamination by organic pollutants is a growing threat to the environment and human health. As a cost-effective method, in situ chemical oxidation (ISCO) treatment has become a popular technical method to degrade groundwater pollutants. However, conventional ISCO treatment can suffer from a number of operational issues, such as tailing and concentration rebound, and thus the long-term treatment effectiveness is less desirable. As an alternative approach to the conventional ISCO method, controlled release materials are designated to gradually release oxidant chemicals to treat polluted groundwater with an extended chemical release duration and a reduced peak release rate. In this study, novel persulfate-paraffin based controlled release bead (CRB) materials were prepared and tested in a laboratory setting for their applicability in groundwater organic pollution remediation. It shows that bead size and temperature can substantially affect the release kinetics of persulfate from the CRBs, while the impact of solution pH and the presence of matrix anions are insignificant. Moreover, degradation experiments of benzene, toluene, ethylbenzene, and xylene pollutants show that the performance of CRBs, particularly within a short period after being delivered in situ, is on par with the conventional ISCO method using aqueous persulfate. This study expands our understanding and capacity in adopting controlled release materials for groundwater remediation. This study promotes the potential field application of such novel controlled release materials for environmental remediation of groundwater.

有机污染物对地下水的污染对环境和人类健康构成日益严重的威胁。作为一种经济有效的方法，原位化学氧化（ISCO）处理已成为一种流行的地下水污染物降解技术方法。然而，传统的 ISCO 处理会受到许多操作问题的影响，例如拖尾和浓度反弹，因此长期处理效果不太理想。作为传统 ISCO 方法的替代方法，控释材料被指定为逐渐释放氧化剂化学物质，以延长化学物质释放持续时间和降低峰值释放速率来处理受污染的地下水。在这项研究中，制备了新型过硫酸盐-石蜡基控释珠 (CRB) 材料，并在实验室环境中对其在地下水有机污染修复中的适用性进行了测试。它表明珠粒大小和温度可以显着影响过硫酸盐从 CRB 的释放动力学，而溶液 pH 值和基质阴离子的存在的影响微不足道。此外，苯、甲苯、乙苯和二甲苯污染物的降解实验表明，CRBs 的性能，特别是在原位交付后的短时间内，与使用过硫酸盐水溶液的常规 ISCO 方法相当。这项研究扩展了我们在采用控释材料进行地下水修复方面的理解和能力。