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The removal of phosphate from water has attracted increasing attention because of the dominant role of phosphate in eutrophication. In this study, a novel nanoscale hybridized adsorbent, NLC@213, was fabricated by immobilizing nanosized lanthanum carbonate (NLC) into the pores of the macro-porous polyacrylic anion exchanger D213 through an in-situ precipitation method for phosphate adsorption from wastewater. NLC@213 exhibited excellent pH tolerance and possessed a high selectivity for phosphate in the presence of competing anions (Cl − , NO 3 − , SO 4 2− , SiO 3 2− , and HCO 3 2− ) and organic acids (humic, tannic, and gallic acids). The maximum phosphate adsorption capacity reached 53.64 mg P/g at 30 °C. Moreover, fixed-bed column adsorption experiments demonstrated that NLC@213 could effectively treat 2400 bed volumes of real secondary effluent (phosphate concentration decreased from 2.0 to <0.5 mg P/L). The exhausted NLC@213 could be regenerated easily using a binary solution of NaCl (1.5 mol/L)−Na 2 CO 3 (3 mol/L), and no significant capacity loss was observed during the recycling for column adsorption−desorption. The underlying mechanism of phosphate adsorption was investigated by a combination of Fourier-transform infrared, transmission electron microscopy, and X-ray photoelectron spectroscopy, and the formation of LaPO 4 •xH 2 O was suggested to be the main pathway in the separation process of phosphate from real secondary effluent.

In this study, a novel asymmetric amine-based strongly basic anion exchange resin SE-1 was synthesized successfully via the reaction of chloromethylated styrene–divinylbenzene copolymer with N, N-dimethyloctylamine. The sorption performance of SE-1 for selective removal of nitrate in aqueous solution was compared to a commercially available nitrate specialty resin, namely Purolite A 520E (A 520E). It was found that the kinetic data could be described better by the pseudo-second-order model, and SE-1 indicated a faster sorption kinetics than A 520E resin. The Langmiur model was more appropriate for explicating the sorption isotherm. Importantly, SE-1 exhibited a greater sorption capacity for nitrate regardless of the absence or presence of competing anions in solutions. The result of column tests reinforced the feasibility of SE-1 for practical application in groundwater treatment.

A novel anion exchange resin AEE-3 was synthesized by N-alkylation of a weakly basic polyacrylic anion exchanger D311 with 1-bromopropane to effectively remove nitrate (NO3−-N) from aqueous solution. The related finding revealed that its adsorption isotherm obeyed the Langmuir model well, and the second-order model was more validated for the NO3−-N adsorption kinetics study. Compared to commercially-available polystyrene-based nitrate specialty resin Purolite A 520E (A520E), AEE-3 resin has a higher adsorbed amount and better regeneration performance toward NO3−-N in the existence of dissolved organic matter (DOM) using static and dynamic methods. Notably, a real secondary treated wastewater (STWW) obtained from a local municipal wastewater treatment plant was also assessed for NO3−-N removal in fixed-bed columns. Observations from this study indicated that AEE-3 could effectively remove NO3−-N from contaminated surface water.

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