ABSTRACT

UV/persulfate (UV/PS) technologies have gained increased attention as efficient alternatives for removing pollutants from different classes, although processes based on the UVA-driven ${\mathrm{S}}_2{\mathrm{O}}_8^{2-}$ (PS) activation have not yet been discussed in the literature for the removal of the nonionic surfactant nonylphenol polyethoxylate (NPEO). The present study investigated the simultaneous effect of the initial persulfate concentration ([PS]₀) and specific photon emission rate (E_P,0) on NPEO degradation by UVA/PS following a Doehlert experimental design. The results for [NPEO]₀ = (4.65 ± 0.15) mg L⁻¹ indicated more than 97.8% NPEO removal after 2 h, with pseudo first-order specific degradation rate (k_obs) of 0.0320 min⁻¹, for [PS]₀ = 7.75 mmol L⁻¹ and E_P,0 = 0.437 μmol photons L⁻¹ s⁻¹. Under these conditions, NPEO half-life time was about 22 min, and the EC₅₀-48 h (% v/v) values for Daphnia similis before and after treatment did not differ significantly. Higher values of E_P,0 would influence NPEO removal for [PS]₀ not higher than 8–10 mmol L⁻¹, although lower degradation efficiencies were obtained with higher [NPEO]₀ or real wastewater, except for longer reaction times. Additionally, UVA/PS showed to be efficient for tensoactivity removal, despite the negligible total organic carbon (TOC) removal achieved. Finally, UVC and UVA resulted in NPEO degradation higher than 96% and similar tensoactivity removals when UVA/PS was conducted under optimal conditions ([PS]₀ = 10 mmol L⁻¹; E_P,0 = 0.324 μmol photons L⁻¹ s⁻¹), suggesting that UVA radiation available in solar light could be advantageously employed for NPEO removal at concentrations usually found in wastewater.

摘要

紫外线/过硫酸盐 (UV/PS) 技术作为去除不同类别污染物的有效替代品而受到越来越多的关注，尽管基于 UVA 驱动的工艺 ${\mathrm{小号}}_2{\mathrm{○}}_8^{2-}$(PS) 活化在文献中尚未讨论去除非离子表面活性剂壬基酚聚乙氧基化物 (NPEO)。本研究根据 Doehlert 实验设计，研究了初始过硫酸盐浓度 ([PS] ₀ ) 和特定光子发射率 ( EP _,0 ) 对 UVA/PS 降解 NPEO的同时影响。[NPEO] ₀  = (4.65 ± 0.15) mg L ^-1的结果表明，对于 [PS]，2 小时后 NPEO 去除率超过 97.8%，伪一级比降解率 ( k _obs ) 为 0.0320 min ^-1 ₀  = 7.75 mmol L ^-1和E _P,0 = 0.437 μmol 光子 L ^-1 s ^-1。在这些条件下，NPEO半衰期约为22分钟，处理前后类水蚤的EC ₅₀ -48 h (% v/v)值无显着差异。较高的E _P,0值会影响不高于 8-10 mmol L ^{-1的 [PS]} ₀的 NPEO 去除，尽管较高的 [NPEO] ₀会获得较低的降解效率或真正的废水，除了更长的反应时间。此外，UVA/PS 显示出可有效去除张力活性，尽管实现的总有机碳 (TOC) 去除可忽略不计。最后，当在最佳条件下进行 UVA/PS（[PS] ₀  = 10 mmol L ^-1；E _P,0  = 0.324 μmol 光子 L ^-1 s ^-1 )，表明太阳光中可用的UVA辐射可以有利地用于去除废水中通常存在的浓度的NPEO。