Adsorption of heavy metal from industrial wastewater onto low-cost Malaysian kaolin clay–based adsorbent

• Published in: Environmental science and pollution research international Vol. 27; no. 12; pp. 13949 - 13962
• Main Authors: Chai, Jia-Boon, Au, Pek-Ing, Mubarak, Nabisab Mujawar, Khalid, Mohammad, Ng, Wendy Pei-Qin, Jagadish, Priyanka, Walvekar, Rashmi, Abdullah, Ezzat Chan
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.04.2020; Springer Nature B.V
• Subjects: Acids; Activated clay; Adsorbents; Adsorption; Aquatic Pollution; Aqueous solutions; Atmospheric Protection/Air Quality Control/Air Pollution; Binding sites; Chemical composition; Clay; Copper; Dosage; Earth and Environmental Science; Ecotoxicology; Electron micrographs; Environment; Environmental Chemistry; Environmental Health; Environmental science; Fourier analysis; Fourier transforms; Heavy metals; Hydrogen-Ion Concentration; Industrial wastes; Industrial wastewater; Infrared analysis; Infrared spectroscopy; Ion concentration; Ions; Kaolin; Kaolinite; Kinetics; Low cost; Metal concentrations; Metal ions; Metals, Heavy; Nickel; pH effects; Refluxing; Research Article; Spectroscopy, Fourier Transform Infrared; Sulfuric acid; Surface chemistry; Surface properties; Waste Water; Waste Water Technology; Wastewater treatment; Water Management; Water Pollutants, Chemical; Water Pollution Control; Zeta potential; Industrial wastewater; Adsorption; Kaolin clay; Heavy metal
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-020-07755-y

Adsorption capacity and percentage removal efficiency of Cu(II) and Ni(II) ions were studied and compared between raw kaolinite and acid-activated kaolinite. Acid-activated kaolin was prepared by refluxing raw kaolinite with concentrated sulphuric acid followed by calcination to enhance its surface properties and adsorption ability. Both raw and acid-activated kaolinite samples were characterized by Fourier transform infrared spectroscopy, energy dispersive X-ray, scanning electron micrograph and zeta potential analysis. Upon acid treatment, acid-activated kaolinite was discovered to have altered chemical composition and larger BET surface area as compared with raw kaolinite. The batch adsorption studies on aqueous solution were performed under different factors such as contact time, pH condition, adsorbent dosage, initial metal ion concentration and temperature. The optimum condition was selected for each factor including a contact time of 60 min, pH of 7.0, adsorbent dosage of 0.1 g, initial metal ion concentration of 100 mg/L and temperature of 25 °C. Then, the adsorption studies on wastewater samples were carried out at the selected optimum conditions. Acid-activated kaolinite always had better adsorption capacity and percentage removal efficiency than raw kaolinite due to the increasing amount of negative charges on the adsorbent surface and the number of metal ion binding sites upon acid treatment. The adsorption kinetic obtained was well described by the pseudo-second-order model, whereas the adsorption isotherms obtained were well described by either the Freundlich or the Langmuir adsorption model. The results showed that acid-activated kaolinite adsorbent is a better option as a favourable and feasible commercial low-cost adsorbent for wastewater treatment.