Neale Peta A, Mastrup Maibritt, Borgmann Thomas, Schäfer Andrea I
School of Engineering, The University of Edinburgh, Edinburgh, UK EH9 3JL.
J Environ Monit. 2010 Jan;12(1):311-7. doi: 10.1039/b913338k. Epub 2009 Oct 29.
Micropollutants occur in natural waters from a range of sources. Estrogenic compounds are naturally excreted by humans and hence stem predominantly from wastewater effluents. Due to their small molecular weight and concentration their effective control is a challenge. In this study magnetic ion exchange (MIEX), which was developed to remove natural organic matter (NOM) from surface water, was investigated for such a micropollutant, estrone. The interaction of estrone with the resin occurs as a side effect when NOM is removed. This interaction results in some degree of removal. However, the accumulation of those hazardous materials on the resin, which can be associated with accidental release, as well as the concentration in the regeneration brine of the process, is environmentally more significant. For this reason a thorough investigation of interaction phenomena was undertaken. Estrone and polymeric materials (such as ion exchange resins or membranes) interact through a number of mechanisms including specific and non-specific interactions. Sorption and desorption of estrone were studied as a function of pH, temperature, natural organic matter concentration, sulfate concentration and ionic strength to elucidate possible mechanisms. The results demonstrated that the resin removed around 70% estrone at high pH conditions (>10.4) when estrone was predominantly negatively charged. However, below pH 10.4, when estrone was neutral, approximately 40% of estrone still sorbed due to hydrogen bonding. The optimum temperature for estrone sorption was observed to be in the 15 to 35 degrees C range, while the presence of other anions, including natural organic matter reduced estrone removal due to competition for anion exchange sites. Desorption of estrone was most effective with 2 M NaCl regeneration brine concentration when estrone was negatively charged (98% desorption). However, when estrone was neutral there was no significant difference between 1 M and 2 M NaCl. The results presented in this study indicate that polar non-ionic micropollutants were removed by magnetic ion exchange resin due to sorption to the resin polymer. This has implications for treatment, however, the accumulation of micropollutants on polymeric materials in water treatment as well as the abundance of such micropollutants in the regeneration brine are risks that warrant monitoring.
微污染物存在于天然水体中，来源广泛。雌激素类化合物是人类自然排泄的产物，因此主要来源于废水排放。由于其分子量小、浓度低，有效控制它们是一项挑战。在本研究中，为从地表水中去除天然有机物（NOM）而开发的磁性离子交换（MIEX）技术，被用于研究去除一种微污染物——雌酮。去除NOM时，雌酮与树脂的相互作用作为一种副作用发生。这种相互作用导致了一定程度的去除。然而，这些有害物质在树脂上的积累，可能与意外释放有关，以及该过程再生盐水中的浓度，在环境方面更为重要。因此，对相互作用现象进行了深入研究。雌酮与聚合材料（如离子交换树脂或膜）通过多种机制相互作用，包括特异性和非特异性相互作用。研究了雌酮的吸附和解吸与pH值、温度、天然有机物浓度、硫酸盐浓度和离子强度的关系，以阐明可能的机制。结果表明，当雌酮主要带负电荷时，在高pH条件下（>10.4），树脂去除了约70%的雌酮。然而，在pH值低于10.4时，当雌酮呈中性时，由于氢键作用，仍有约40% 的雌酮被吸附。观察到雌酮吸附的最佳温度在15至35摄氏度范围内，而其他阴离子（包括天然有机物）的存在由于竞争阴离子交换位点而降低了雌酮的去除率。当雌酮带负电荷时，用2M NaCl再生盐水浓度进行雌酮解吸最为有效（98% 解吸）。然而，当雌酮呈中性时，1M和2M NaCl之间没有显著差异。本研究结果表明，极性非离子微污染物通过吸附到树脂聚合物上而被磁性离子交换树脂去除。这对处理有影响，然而，微污染物在水处理中的聚合材料上的积累以及再生盐水中此类微污染物的大量存在是需要监测的风险。
