Selective removal of nitrate using a novel asymmetric amine based strongly basic anion exchange resin

Abstract

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.

Vacancy-cluster-mediated surface activation for boosting CO2 chemical fixation

“…To gain in-depth understanding on the effects of Fe-Cl vacancy cluster in cycloaddition of CO 2 with epoxides, in-situ diffuse reflectance infrared Fourier-transform spectroscopy (insitu DRIFTS) measurements were carried out, 40 where the catalyst and PO were mixed in a reaction chamber under 0.3-MPa CO 2 atmosphere at 413 K. According to Figure S19, the ring-opening of PO is evidenced by gradually increasing of the peak around ~670 cm -1 that could be assigned to the formation of C-Cl bond. [41][42][43] Such a feature clearly confirms that Cl atom at Fe-Cl vacancy cluster could serve as an electron-donor unit for attacking the electrophilic carbon atom of PO. As shown in Figure 4a and 4b, the peak around 1047 cm -1 , which could be assigned to symmetric stretching vibrations of C-O species 44 , was improved with the increasing of reaction time, confirming the significant ring opening of PO by FeOCl-V Fe-Cl .…”

“…S19, † the ringopening of PO is evidenced by a gradually increase in the peak at around ∼670 cm −1 that could be assigned to the formation of a C-Cl bond. [41][42][43] Such a feature clearly conrms that a Cl atom at an Fe-Cl vacancy cluster could serve as an electron-donor unit for attacking the electrophilic carbon atom of PO. As shown in Fig.…”

Spatiotemporal Variation of Groundwater Quality in North Central Province, Sri Lanka

“…Due to a lower dissolved mineral content, the ion exchange process can be suggested as an efficient and cost-effective way for nitrate removal without much interruption of other constituents in the groundwater compared to membrane-based technologies. This process has long been used for nitrate removal in drinking water production using nitrate selective or nonselective resins which are commercially available and show higher performances. − …”

Nitrate removal from aqueous solutions with sodium alginate/quaternary branched polyethylenimine/carboxylated multi-wall carbon nanotube

“…The C=O stretching vibrations of carboxylic groups appeared at 1660 cm -1 [33]. The asymmetric N-O stretching vibrations occur at 1340 [35] (Fig. 2).…”