title: Arsenic removal from high-arsenic water by enhanced coagulation with ferric ions and coarse calcite.
abstract: Arsenic removal from high-arsenic water in a mine drainage system has been studied through an enhanced coagulation process with ferric ions and coarse calcite (38-74 microm) in this work. The experimental results have shown that arsenic-borne coagulates produced by coagulation with ferric ions alone were very fine, so micro-filtration (membrane as filter medium) was needed to remove the coagulates from water. In the presence of coarse calcite, small arsenic-borne coagulates coated on coarse calcite surfaces, leading the settling rate of the coagulates to considerably increase. The enhanced coagulation followed by conventional filtration (filter paper as filter medium) achieved a very high arsenic removal (over 99%) from high-arsenic water (5mg/l arsenic concentration), producing a cleaned water with the residual arsenic concentration of 13 microg/l. It has been found that the mechanism by which coarse calcite enhanced the coagulation of high-arsenic water might be due to attractive electrical double layer interaction between small arsenic-borne coagulates and calcite particles, which leads to non-existence of a potential energy barrier between the heterogeneous particles.
authors.affiliation: Instituto de Metalurgia, Universidad Autónoma de San Luis Potosí, Avenida Sierra Leona 550, San Luis Potosí, C. P. 78210, Mexico. shaoxian@uaslp.mx
authors.forename: S
authors.initials: S
authors.lastname: Song
authors.forename: A
authors.initials: A
authors.lastname: Lopez-Valdivieso
authors.forename: D J
authors.initials: DJ
authors.lastname: Hernandez-Campos
authors.forename: C
authors.initials: C
authors.lastname: Peng
authors.forename: M G
authors.initials: MG
authors.lastname: Monroy-Fernandez
authors.forename: I
authors.initials: I
authors.lastname: Razo-Soto
mesh_terms: D001151:Arsenic / Q000737:chemistry / Q000302:isolation & purification*; D002119:Calcium Carbonate / Q000737:chemistry; D005374:Filtration; D007501:Iron / Q000737:chemistry; D008906:Mining; D014873:Water Pollutants / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D014873:Water Pollutants; D007501:Iron; D002119:Calcium Carbonate; D001151:Arsenic