TAILIEUCHUNG - INTERFACIAL APPLICATIONS IN ENVIRONMENTAL ENGINEERING - CHAPTER 7

Thiết kế và tổng hợp của vật liệu mới để khắc phục chất thải nặng phần tử Nghiên cứu về việc tách các chất ô nhiễm ion từ hệ thống dung dịch nước là tập trung vào việc tối ưu hóa nhiều thông số, bao gồm cả chi phí, năng lực, chọn lọc, và ổn định tổng thể. Phòng thí nghiệm của chúng tôi đã được quan tâm trong các tài liệu phát triển như extractants trao đổi ion cho việc loại bỏ và thu hồi "mềm" cation kim loại nặng như thủy ngân, cadmium và chì từ các dòng thải. | 7 Design and Synthesis of New Materials for Heavy Element Waste Remediation LISA DYSLESKI SARAH E. FRANK STEVEN H. STRAUSS and PETER K. DORHOUT Colorado State University Fort Collins Colorado . I. INTRODUCTION Research on the separation of ionic pollutants from aqueous systems is focused on the optimization of many parameters including cost capacity selectivity and overall stability. Our labs have been interested in developing materials as ion exchange extractants for the removal and recovery of soft heavy metal cations such as mercury cadmium and lead from aqueous waste streams 1-5 . As a result of these studies we have determined that the requirements for an ideal extractant are selectivity for soft metal cations such as Hg2 Pb2 and Cd2 over hard cations such as Na Li Mg2 and Cr3 the ability to recover the target soft heavy metal ion in a minimal volume of secondary waste and the ability of the material to operate effectively through numerous extraction cycles. In order to satisfy each of these requirements we have focused our efforts on sulfur-based materials with one or more exchangeable cations. It is our hypothesis that a material with a sulfur-rich environment will preferentially exchange hard cations held within the solid for soft cations in aqueous solution according to Lewis hard-soft acid-base theory 6 moreover another hypothesis is that it is important that the material has an open or flexible framework so that ion exchange is facile and so that it is able to withstand repeated ion exchange reactions. II. LAYERED METAL CHALCOGENIDES In the past we have explored two types of remediation materials based on our hypotheses. The first type was based on zirconium monothiophosphate Copyright n 2003 by Marcel Dekker Inc. All Rights Reserved. FIG. 1 Structural representation of H2Zr PO3S 2. Striped polyhedra are thiophosphates filled circles are zirconium and open circles located in the interlayer space of the material are sulfur atoms with their associated

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