title: Effective solidification/stabilisation of mercury-contaminated wastes using zeolites and chemically bonded phosphate ceramics.
abstract: In this study, two kinds of zeolites materials (natural zeolite and thiol-functionalised zeolite) were added to the chemically bonded phosphate ceramic processes to treat mercury-contaminated wastes. Strong promotion effects of zeolites (natural zeolite and thiol-functionalised zeolite) on the stability of mercury in the wastes were obtained and these technologies showed promising advantages toward the traditional Portland cement process, i.e. using Portland cement as a solidification agent and natural or thiol-functionalised zeolite as a stabilisation agent. Not only is a high stabilisation efficiency (lowered the Toxicity Characteristic Leaching Procedure Hg by above 10%) obtained, but also a lower dosage of solidification (for thiol-functionalised zeolite as stabilisation agent, 0.5 g g(-1) and 0.7 g g(-1) for chemically bonded phosphate ceramic and Portland cement, respectively) and stabilisation agents (for natural zeolite as stabilisation agent, 0.35 g g(-1) and 0.4 g g(-1) for chemically bonded phosphate ceramic and Portland cement, respectively) were used compared with the Portland cement process. Treated by thiol-functionalised zeolite and chemically bonded phosphate ceramic under optimum parameters, the waste containing 1500 mg Hg kg(-1) passed the Toxicity Characteristic Leaching Procedure test. Moreover, stabilisation/solidification technology using natural zeolite and chemically bonded phosphate ceramic also passed the Toxicity Characteristic Leaching Procedure test (the mercury waste containing 625 mg Hg kg(-1)). Moreover, the presence of chloride and phosphate did not have a negative effect on the chemically bonded phosphate ceramic/thiol-functionalised zeolite treatment process; thus, showing potential for future application in treatment of 'difficult-to-manage' mercury-contaminated wastes or landfill disposal with high phosphate and chloride content.
authors.affiliation: Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, People's Republic of China.
authors.forename: Shaoqing
authors.initials: S
authors.lastname: Zhang
authors.affiliation: School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, Changchun, People's Republic of China.
authors.forename: Xinyan
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Beijing Municipal Research Institute of Environmental Protection, Beijing, People's Republic of China.
authors.forename: Ya
authors.initials: Y
authors.lastname: Xiong
authors.affiliation: Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, People's Republic of China.
authors.forename: Guoping
authors.initials: G
authors.lastname: Wang
authors.affiliation: Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, People's Republic of China zhengnalzz@neigae.ac.cn zhengnalzz@hotmail.com.
authors.forename: Na
authors.initials: N
authors.lastname: Zheng
mesh_terms: D002516:Ceramics / Q000737:chemistry; D006256:Hazardous Waste; D008628:Mercury / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry; D013438:Sulfhydryl Compounds / Q000737:chemistry; D018505:Waste Management / Q000191:economics / Q000379:methods*; D017641:Zeolites / Q000737:chemistry*
chemical_list: D006256:Hazardous Waste; D010710:Phosphates; D013438:Sulfhydryl Compounds; D017641:Zeolites; D008628:Mercury
keywords: Chemically bonded phosphate ceramics; mercury-contaminated wastes; solidification/stabilisation; zeolites