Preparation of Manganese-Iron Oxide Coated Rice Husk Ash Silica Xerogel for Removal of Heavy Metals in Wastewater

  • Karnmanee Thongsri นักศึกษา หลักสูตรวิทยาศาสตรมหาบัณฑิต สาขาวิทยาสาสตร์สิ่งแวดล้อม คณะสิ่งแวดล้อม มหาวิทยาลัยเกษตรศาสตร์
  • Nipon Tungkananuruk รองศาสตราจารย์ ภาควิชาวิทยาสาสตร์สิ่งแวดล้อม คณะสิ่งแวดล้อม มหาวิทยาลัยเกษตรศาสตร์
  • Kanita Tungkananuruk รองศาสตราจารย์ ภาควิชาวิทยาสาสตร์สิ่งแวดล้อม คณะสิ่งแวดล้อม มหาวิทยาลัยเกษตรศาสตร์
  • Watcharapong Wararam อาจารย์ ภาควิชาวิทยาสาสตร์สิ่งแวดล้อม คณะสิ่งแวดล้อม มหาวิทยาลัยเกษตรศาสตร์
Keywords: Rice husk, Silica, Adsorption


This research was to prepare low cost adsorbents that had significant potential for modification and enhancement of heavy metals adsorption capabilities. Silica from extraction of rice husk ash and coated with manganese and iron oxides was prepared. The adsorption capabilities of various ratios of coating Fe and Mn (Fe100, Fe80, Fe60, Fe40, Fe20 and Mn100) were investigated in Pb, Cd, Ni and Zn solutions by batch experiments. The results showed that in each heavy metal solution (40 mg/L), Fe20 and Mn100 coated silica showed the same high adsorption capability around 3.8-4.0 mg/g. The adsorption mechanism of both Pb and Cd on Mn100 coated silica was agreed with Langmuir and Freundlich. In addition, application of Mn100 coated silica for heavy metals treatment in 500 mL of the synthetic wastewater was conducted on jar test apparatus. The maximum removal efficiencies obtained were 99.87% Pb, 95.40% Cd, 95.90% Ni and 95.02% Zn at pH 7, agitation at 50 rpm/min for 15 min and 1 g of adsorbent. Therefore, this chemically modified silica had a high potential for removals of  Pb, Cd, Ni and Zn in wastewater.


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