title: Preliminary study on removing Cs⁺/Sr²⁺ by activated porous calcium silicate-A by-product from high-alumina fly ash recycling industry.
abstract: ¹³⁷Cs⁺/⁹⁰Sr²⁺-containing radioactive wastewater is one of the most important problems that the world has been facing with. A by-product, activated porous calcium silicate, is generated at high levels by the pre-desiliconizing and soda-lime-sintering processes for producing Al₂O₃from high-alumina fly ash. In order to examine if this by-product could be used as an absorbent for removal of ¹³⁷Cs⁺/⁹⁰Sr²⁺ from radioactive wastewater, various parameters, such as pH, adsorbent dose, contact time, and initial concentration, were discussed. Results indicated that the equilibrium reached in about 2 hr. Activated porous calcium silicate was highly pH sensitive and able to remove Cs(+)/Sr²⁺ in a near-neutral environment. The adsorption equilibrium was best described by Freundlich isotherm equations, and the adsorption of Cs⁺/Sr²⁺ was a physical process. The adsorption kinetic data could be better fitted by the pseudo-second-order model, and the adsorption was controlled by multidiffusion. Current study showed that activated porous calcium silicate has a good adsorption of Cs⁺/Sr²⁺ for their removal. However, other characteristics, such as selectivity because of coexisting cations, elution and regeneration, thermal stability, and acid resistance, should be discussed carefully before using it in an actual field.
authors.affiliation: a Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education , Southwest University of Science and Technology , Mianyang , P.R. China.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Chu
authors.forename: Rong
authors.initials: R
authors.lastname: Wang
authors.forename: Mengjun
authors.initials: M
authors.lastname: Chen
mesh_terms: D000327:Adsorption; D017610:Calcium Compounds / Q000737:chemistry*; D002588:Cesium Radioisotopes / Q000737:chemistry; D060729:Coal Ash; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D059027:Recycling; D017640:Silicates / Q000737:chemistry*; D013326:Strontium Radioisotopes / Q000737:chemistry; D013816:Thermodynamics; D014875:Water Pollutants, Radioactive / Q000737:chemistry*
chemical_list: D017610:Calcium Compounds; D002588:Cesium Radioisotopes; D060729:Coal Ash; D017640:Silicates; D013326:Strontium Radioisotopes; D014875:Water Pollutants, Radioactive; C031293:calcium silicate