文章信息/Info

Title:

Calcium Phosphate Glass as Curing Agent for Heavy Metal Ions in Soil and Tailings

作者:

鄭章宏; 袁宇興; 湯裕; 盧安賢

中南大學材料科學與工程學院，湖南 長沙 410083

Author(s):

ZHENG Zhanghong;  YUAN Yuxing;  TANG Yu;  LU Anxian

School of Materials Science and Engineering, Central South University, Changsha 410083, China

關鍵詞:

磷酸鈣玻璃; 重金屬離子; pH值; CaO/P2O5比; 固化率

Keywords:

Calcium phosphate glass;  heavy metal ions;  pH value;  CaO/P2O5 ratio;  immobilization rate

DOI:

10.7502/j.issn.1674-3962.2018.06.08

文獻標志碼:

A

摘要:

利用傳統熔體冷卻法制備了磷酸鈣玻璃（CPG），研究了該玻璃對土壤和鉛鋅礦尾礦中Pb和Cd離子的固化行為。結果表明，四種不同組分的CPG對降低Pb和Cd離子濃度都有較好效果，與Cd離子相比，Pb離子濃度降低輻度更大；CPG中的CaO/P2O5摩爾比及CPG在溶液中的溶解度直接影響其對重金屬離子的固化效果。當CaO/P2O5比例為4∶6時，CPG對被污染土壤和鉛鋅礦尾礦中的Pb和Cd離子固化率達到最高。由于對Pb離子的固化屬溶解沉淀機制，而對Cd離子的固化則為表面吸附與絡合作用，因此，Pb離子的固化比Cd離子的固化對pH值更敏感。研究發現，用CPG溶液固化被污染土壤和鉛鋅礦尾礦時Pb, Cd離子的最佳pH值分別為4和5，其最大固化率分別為70��12％與69��05％和58��22％與52��74％。

Abstract:

Calcium phosphate glasses (CPGs) have been prepared by the conventional melting quenching method. The immobilizing behavior and effects of CPG solution to Pb and Cd ions in contaminated soils and lead zinc mine tailings have been studied. The results showed that four CPG solutions with different CaO/P2O5 ratio have excellent effects on reducing the concentration of Pb and Cd ions. Compared with the immobilizing Cd ions, the CPG solutions have better effects when it was used to immobilize Pb ions in both contaminated soils and lead zinc mine tailings. The immobilizing effect on heavy metal ions depends directly on the CaO/P2O5 ratio and solubility of CPG solution. When the CaO/P2O5 ratio of CPG is 4∶6, the highest immobilization rate of Pb and Cd ions in the solution was observed. PH value has more obvious effects on the immobilization of Pb ions than that of Cd ions. The possible reason is the former belongs to the mechanism of precipitation and dissolution, but the later is attributed to the surface absorption and complexation mechanism. The optimum pH value for immobilizing Pb and Cd ions from contaminated soil and lead zinc mine tailings with CPG solution is 4 and 5, respectively. The maximum immobilization rate on Pb and Cd ions is 70��12% ,69��05% and 58��22% and 52��74%, respectively.