Chromium Removal from Aqueous Solution Using Natural Clinoptilolite

Tonni Agustiono Kurniawan, Mohd Hafiz Dzarfan Othman, Mohd Ridhwan Adam, Xue Liang, Huihwang Goh, Abdelkader Anouzla, Mika Sillanpää, Ayesha Mohyuddin, Kit Wayne Chew

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)


This work investigates the applicability of clinoptilolite, a natural zeolite, as a low-cost adsorbent for removing chromium from aqueous solutions using fixed bed studies. To improve its removal performance for the inorganic pollutant, the adsorbent is pretreated with NaCl to prepare it in the homoionic form of Na+ before undertaking ion exchange with Cr3+ in aqueous solution. This work also evaluates if treated effluents could meet the required effluent discharge standard set by legislation for the target pollutant. To sustain its cost-effectiveness for wastewater treatment, the spent adsorbent is regenerated with NaOH. It was found that the clinoptilolite treated with NaCl has a two-times higher Cr adsorption capacity (4.5 mg/g) than the as-received clinoptilolite (2.2 mg/g). Pretreatment of the clinoptilolite with NaCl enabled it to treat more bed volume (BV) (64 BV) at a breakthrough point of 0.5 mg/L of Cr concentration and achieve a longer breakthrough time (1500 min) for the first run, as compared to as-received clinoptilolite (32 BV; 250 min). This suggests that pretreatment of clinoptilolite with NaCl rendered it in the homoionic form of Na+. Although pretreated clinoptilolite could treat the Cr wastewater at an initial concentration of 10 mg/L, its treated effluents were still unable to meet the required Cr limit of less than 0.05 mg/L set by the US Environmental Protection Agency (EPA).

Original languageEnglish
Article number1667
JournalWater (Switzerland)
Issue number9
Publication statusPublished - May 2023


  • adsorption
  • clinoptilolite
  • ion exchange
  • low-cost adsorbent
  • water pollution
  • zeolite

ASJC Scopus subject areas

  • Biochemistry
  • Geography, Planning and Development
  • Aquatic Science
  • Water Science and Technology


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