The investigation into the adsorption removal of ammonium by natural and modified zeolites: kinetics, isotherms, and thermodynamics

  • Min Pan Key Laboratory of Environmental Biotechnology (XMUT), Fujian Province University, School of Environmental Science and Engineering, Xiamen University of Technology, Xiamen, 361024, China
  • Mingchuan Zhang College of Resources and Civil Engineering, Northeastern University, Shenyang, 110819, China
  • Xuehua Zou Laboratory of Nanomineralogy and Environmental Material, School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China
  • Xuetong Zhao Key Laboratory of Environmental Biotechnology (XMUT), Fujian Province University, School of Environmental Science and Engineering, Xiamen University of Technology, Xiamen, 361024, China
  • Tianran Deng Key Laboratory of Environmental Biotechnology (XMUT), Fujian Province University, School of Environmental Science and Engineering, Xiamen University of Technology, Xiamen, 361024, China
  • Tong Chen Key Laboratory of Environmental Biotechnology (XMUT), Fujian Province University, School of Environmental Science and Engineering, Xiamen University of Technology, Xiamen, 361024, China
  • Xiaoming Huang 1. Key Laboratory of Environmental Biotechnology (XMUT), Fujian Province University, School of Environmental Science and Engineering, Xiamen University of Technology, Xiamen, 361024, China; 2. Laboratory of Nanomineralogy and Environmental Material, School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China
Keywords: zeolite, sodium chloride modified, adsorbent, regeneration, wastewater

Abstract

The objectives of this study were to modify Chinese natural zeolite by NaCl and to investigate its suitability as a low-cost clay adsorbent to remove ammonium from aqueous solution. The effect of Ph on ammonium removal was investigated by batch experiments. The findings indicated that Ph has a significant effect on the removal of ammonium by M-Zeo and maximum adsorption occurred at Ph 8. Ion exchange dominated the ammonium adsorption process at neutral Ph, with the order of exchange selectivity being Na+ > Ca2+ > K+ > Mg2+. The Freundlich model provided a better description of the adsorption process than the Langmuir model. The maximum ammonium adsorption capacity was 17.83 mg/g for M-Zeo at 293K. Considering the adsorption isotherms and thermodynamic studies, the adsorption of ammonium by M-Zeo was endothermic and spontaneous chemisorption. Kinetic studies indicated that the adsorption of ammonium onto M-Zeo is well fitted by the pseudo-second-order kinetic model. Ea in the Arrhenius equation suggested the adsorption of ammonium on M-Zeo was a fast and diffusion-controlled process. The regeneration rate was 90.61% after 5 cycles. The removal of ammonium from real wastewater was carried out, and the removal efficiency was up to 99.13%. Thus, due to its cost-effectiveness and high adsorption capacity, M-Zeo has potential for use in ammonium removal from aqueous solutions.

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Published
2019-10-29
Section
Research paper