Preparation and performance of arsenate (V) adsorbents derived from concrete wastes

• Published in: Waste management (Elmsford) Vol. 34; no. 10; pp. 1829 - 1835
• Main Authors: Sasaki, Takeshi, Iizuka, Atsushi, Watanabe, Masayuki, Hongo, Teruhisa, Yamasaki, Akihiro
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.10.2014
• Subjects: Adsorbents; Adsorption; Arsenate removal; Arsenates - chemistry; Arsenic; Arsenic - chemistry; Calcium Compounds - chemistry; Cements; Concretes; Heat treatment; Industrial Waste - analysis; Mathematical analysis; Sludge; Waste cement; Waste concrete; Wastes; Water Pollutants, Chemical - chemistry; Water pollution; Water Purification - methods; Waste cement; Water pollution; Waste concrete; Adsorption; Arsenate removal
• ISSN: 0956-053X; 1879-2456
• DOI: 10.1016/j.wasman.2014.01.001

•Solid adsorbents were prepared from waste cement powder and concrete sludge.•Arsenic removal performances of the prepared materials were assessed.•The arsenic removal mechanism was considered to involve Ca3(AsO4)2 precipitation.•The observed lowest arsenic concentration meets the previous WHO guideline value. Solid adsorbent materials, prepared from waste cement powder and concrete sludge were assessed for removal of arsenic in the form of arsenic (As(V)) from water. All the materials exhibited arsenic removal capacity when added to distilled water containing 10–700mg/L arsenic. The arsenic removal isotherms were expressed by the Langmuir type equations, and the highest removal capacity was observed for the adsorbent prepared from concrete sludge with heat treatment at 105°C, the maximum removal capacity being 175mg-As(V)/g. Based on changes in arsenic and calcium ion concentrations, and solution pH, the removal mechanism for arsenic was considered to involve the precipitation of calcium arsenate, Ca3(AsO4)2. The enhanced removal of arsenic for the adsorbent prepared from concrete sludge with heat treatment was thought to reflect ion exchange by ettringite. The prepared adsorbents, derived from waste cement and concrete using simple procedures, may offer a cost effective approach for arsenic removal and clean-up of contaminated waters, especially in developing countries.