Yuanyuan Wang,Chong Huang,Haixu Wu,Jeng Yi Chong,Ping Zhang
Mineral scaling poses major operational challenges in water-transporting systems across various industries, leading to substantial economic losses globally. Scale inhibitors are specialty chemical agents with functional groups to prevent or interfere with scale formation. Traditionally, scale inhibitors are introduced into water-transporting systems through continuous injection. However, this approach is limited by its short protection duration and reliance on continuous inhibitor injection, which results in high capital and operating costs, as well as increased chemical waste. To address this issue, this study synthesized cement-based controlled release beads (CRBs) loaded with 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) scale inhibitor for scale control. The release performance of HEDP from the CRBs was systematically evaluated through static batch and dynamic column experiments. Quartz crystal microbalance with dissipation monitoring (QCM-D) and turbidity tests confirmed the effectiveness of the CRBs in inhibiting BaSO 4 scale formation. Batch experiments demonstrated that increasing CRB size and lowering the temperature could reduce the release rate of HEDP while prolonging the release duration, without changing the total amount of HEDP released. Dynamic column experiments revealed that higher temperatures resulted in higher peak concentrations of HEDP and earlier peak occurrences, while increasing flow velocity shifted the release curves slightly backward and shortened the overall release time. The presence of Ca 2+ and HCO 3 − ions had no noticeable effect on the dynamic release behavior. These findings deepen our understanding of the release mechanisms of scale inhibitors from cement-based CRBs and highlight their potential as an innovative and sustainable solution for long-term scaling control in water-transporting systems.
Jie Ma,Yao Ma,Xun Rong,Quanwei Song,Baichun Wu,Xingying Lan,Yuan Feng,Xiaoyuan Qiu,Ping Zhang
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.
危险品化学品经营许可证（带存储）