EXPERIMENTAL RESULTS OF ADSORPTION OF Ni (II) FROM WASTEWATER USING COFFEE HUSK BASED ACTIVATED CARBON

In recent years, the studies on finding the low cost methods to remove metal ions have been increased. Use of agricultural wastes such as coffee husk, coffee residue, coconut fiber, rice husk, peanut shells, cob, etc. as adsorbents to remove heavy metals, pollutants in wastewater has been of great concern in Viet Nam and regional countries. The results showed that the material from coffee husk had superior adsorption. In this study, the coffee husk was heated in Ar gas at temperatures of 300 oC, 400 oC, 500 oC, 600 oC for 30 minutes, 60 minutes and 90 minutes, then was denatured by impregnation with HNO3 at different concentrations (1M, 3M, 5M). The adsorbent products from the above process from coffee husk were tested to find the best technical solution by studying the influences of pH (2 ÷ 9), contact time (10 ÷ 100 min), adsorbent dose (0.2 ÷ 10 g/L) and initial concentration Ni(II) (10 ÷ 60 mg/L). The research results showed that while the activated carbon samples treated at 400 oC in 30 minutes had Ni (II) adsorption capacity of 1.97 mg/g, the activated carbon by HNO3 had Ni (II) adsorption higher capacity, maximum adsorption capacity is 21.14 mg/g (more than 10 times in comparison with the non-denatured or non-modified coal).