Treatment of wastewater containing high concentrations of ammonia nitrogen using ion exchange resins

Abstract

Nitrogen in water will induce active biogeochemical effects, such as denitrification and anammox, which release N 2 O, a greenhouse gas, leading to increasing global warming. Therefore, it is necessary to find an economical and efficient method to treat ammonia nitrogen in the field of wastewater treatment. In this study, two cation exchange resins, D61 and D708, were selected to analyze external environment conditions suitable for the adsorption of ammonia nitrogen by conducting orthogonal experiments. The kinetic and thermodynamic mechanisms were discussed, and cation exchange resins with a high selectivity to NH 4 + were selected. The optimum adsorption temperature, pH, and rotation speed for the D61 resin were found to be 32 C, 5, and 150 r/min, respectively. The optimum adsorption temperature and rotation speed for the D708 resin were 40 C and 150 r/min, respectively. The kinetic data could be accurately described using the pseudo-second-order kinetic equation. The results showed that physical and chemical adsorption mechanisms may coexist in the adsorption of NH 4 + -N. The adsorption process can easily occur and that it is not limited by the pH or rotational speed. The maximum adsorption capacities of the D61 and D708 resins were 44.93 and 31.34 mg/g, respectively; removing ammonia nitrogen from 1 m3 of wastewater requires only 100-110 g of ion exchange resin. The cost is $1.78/m 3 of raw wastewater treated. This is a good alternative to other nitrogen removal systems, particularly in comparison with conventional physicochemical methods and the nitrification-denitrification biochemical process employed currently.

Research progress of environment-responsive hydrogel applications in agriculture

“…The crops are rich in metal ions and seriously damage human health. Adsorption of heavy metal ions in the ground is a significant task, and commonly used wastewater Treatment methods include the chemical precipitation method [78], ion exchange resin method [79], adsorption method [80], etc. The most economical and widely used way to treat heavy metal ions in wastewater is to use natural adsorbent materials (e.g., peat, diatom-based soil, vermiculite).…”

Enhanced NH4+ Removal and Recovery from Wastewater Using Na-Zeolite-based Flow-Electrode Capacitive Deionization: Insight from Ion Transport Flux

“…Natural zeolite, a microporous-type aluminosilicate mineral, is abundant on earth and is commercially available at a low cost. − Zeolite is primarily composed of SiO 4 and AlO 4 tetrahedra connected via oxygen atoms, forming negatively charged cage-like three-dimensional (3D) framework structure units filled with metal ions, such as Na + , K + , Mg 2+ , and Ca 2+ , which are mobile and exchangeable with other surrounding cations like NH 4 + . Compared to commercial adsorbents such as AC and resins, zeolite has a higher NH 4 + adsorption capacity than AC (∼30 vs. 0.2–0.8 mg-N/g) and much lower prices than resins (0.03–0.12 vs. ∼14.8 USD/kg). − Therefore, zeolite has been widely used as an adsorbent and filter material in water and wastewater treatment. , In this study, we mixed zeolite with a small amount of highly conductive carbon black (CB) to prepare a composite and a more conductive flow electrode for enhanced NH 4 + removal and recovery through FCDI. To increase the adsorption selectivity of NH 4 + over Na + , we subjected zeolite to Na + exchange to produce Na-zeolite.…”