Tang Shoufeng, Tang Jiachen, Yuan Deling, Wang Zetao, Zhang Yating, Rao Yandi
Hebei Key Laboratory of Heavy Metal Deep-Remediation in Water and Resource Reuse, Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University Qinhuangdao PR China
RSC Adv. 2020 May 6;10(30):17627-17634. doi: 10.1039/d0ra01787f. eCollection 2020 May 5.
Humic substances are polyelectrolytic macromolecules; their presence in water leads to many environmental problems without effective treatment. In this work, the elimination of humic acid (HA), a typical humic substance, has been examined through ultraviolet (UV) activation systems in the presence of peroxydisulfate (PDS) and peroxymonosulfate (PMS), respectively. The results indicated that 92.9% and 97.1% of HA were eliminated with rate constants of 0.0328 ± 0.0006 and 0.0436 ± 0.0011 min with 180 and 60 min treatment times at pH 6 and 3 when adding 3 and 1 mmol L oxidant during UV/PDS and UV/PMS, respectively; the corresponding electric energies per order were 0.0287 and 0.0131 kW h m. The HA removal was systematically investigated by varying different reaction parameters, including radical scavengers, persulphate dose, solution pH, and initial HA concentration, and by addition of various common ions. Moreover, the decomposition details were identified through the changes in the dissolved organic carbon, unique UV absorbances, and UV spectroscopic ratios. Furthermore, the destruction mechanism was verified by fluorescence spectroscopy, demonstrating that the HA structure was decomposed to small molecular fractions in the two UV/persulphate systems. In addition, the purification of HA by the two UV/persulphate processes was assessed in actual water matrices.
腐殖质是聚电解质大分子；若未经有效处理，它们在水中的存在会引发诸多环境问题。在本研究中，分别通过在过二硫酸盐（PDS）和过一硫酸盐（PMS）存在下的紫外（UV）活化系统，考察了典型腐殖质腐殖酸（HA）的去除情况。结果表明，在pH值为6和3时，分别添加3和1 mmol/L的氧化剂进行UV/PDS和UV/PMS处理，处理时间为180和60分钟时，HA的去除率分别为92.9%和97.1%，速率常数分别为0.0328±0.0006和0.0436±0.0011 min⁻¹；相应的每级电能分别为0.0287和0.0131 kW h m⁻³。通过改变不同反应参数，包括自由基清除剂、过硫酸盐剂量、溶液pH值和初始HA浓度，并添加各种常见离子，系统地研究了HA的去除情况。此外，通过溶解有机碳、独特紫外吸光度和紫外光谱比值的变化确定了分解细节。此外，通过荧光光谱验证了破坏机制，表明在两种UV/过硫酸盐系统中，HA结构被分解为小分子部分。此外，还在实际水基质中评估了两种UV/过硫酸盐工艺对HA的净化效果。
