PDF《改性钙 基 吸附剂对垃 圾焚 烧模拟烟气中镉的吸附》

卢欢亮 ,王伟.

改性钙基吸附剂对垃圾焚烧模拟烟气中镉的吸附研究[J ]. 环境科学学报 ,2005 ,25(8) :999 -

1003 LU Huanliang , WANG Wei. Cd vapor adsorption of modified calcium2based adsorbents in simulated MSW flue gases[J ]. Acta Scientiae Circumstantiae ,2005 ,25 (8) :999 -

1003 改性钙基吸附剂对垃圾焚烧模拟烟气中镉的吸附 研究 卢欢亮 ,王伟3清华大学环境科学与工程系 ,北京

100084 收稿日期 :2004209215 修回日期:2005205224 录用日期 :2005206215 摘要 :采用不同的改性方法对轻质碳酸钙进行改性 , 制得一系列改性钙基吸附剂 ,利用 BET、 XRD 和AES2EDS 等方法研究其理化性能 ,并在垃 圾焚烧模拟烟气条件下验证了改性钙基吸附剂对重金属镉的吸附性能. 结果表明 ,高温热活化方法所得的产品为 CaO ,其比表面积从

7134 m2 ・ g -

1 增加到

18127 m2 ・ g -

1 ,盐浸泡煅烧所得的产品为 CaOΠ NaCl 共晶体 ,其层间距比 CaO 增大了

010319 3 nm ,具有良好的表面活性和孔隙结 构 ;

与轻质碳酸钙相比 ,改性钙基吸附剂对镉的吸附效果明显提高 ;

CaO 的吸附机理主要以物理吸附为主 ,CaOΠ NaCl 则以化学吸附为主. 关键词 :改性钙基吸附剂 ;

模拟烟气 ;

镉;

吸附 文章编号 :025322468(2005)

0820999205 中图分类号 :X70112 文献标识码 :A Cd vapor adsorption of modified calcium2based adsorbents in simulated MSW flue gases LU Huanliang , WANG Wei

3 Department of Environmental Science and Engineering , Tsinghua University , Beijing

100084 Received

15 September

2004 ;

received in revised form

24 May

2005 ;

accepted

15 June

2005 Abstract : A series of calcium2based adsorbents were prepared from light calcium carbonate by various modification methods. The physical characteristics of the modified substrates were inspected using BET specific area analyzer , XRD , and AES2EDS spectra. Their adsorption capacities for Cd were examined by introducing CdCl2 vapor into a flue gas system simulating waste incineration. The results showed that the main product after thermal treatment was CaO and the BET specific area of CaO increased dramatically from

7134 m2 ・ g-

1 to

18127 m2 ・ g-

1 after the treatment. The product of salt soaking2calcination was eutectic CaOΠ NaCl and the interlayer distance between the eutectic layers was

0103193 nm larger than that of CaO crystal. Therefore , the eutectic CaOΠ NaCl had high surface activity and developedpore structure. The Cd adsorption capacities of the modified products were also greatly improved compared to light calcium carbonate. The main mechanism of Cd adsorption was physical sorption for CaO , and chemical adsorption for CaOΠ NaCl. Keywords:modified calcium2based adsorbent ;

simulated flue gases ;

Cd ;

adsorption 基金项目 :国家自然科学基金(No. 20277024) 作者简介 :卢欢亮(1981 ― ) ,男 ,硕士研究生 ,E2mail :luhuanliang @tsinghua.org. cn ;

3 通讯作者(责任作者) Foundation item:National Natural Science Foundation of China (No. 20277024) Biography :LU Huanliang(1981 ― ) ,male , master candidate , E2mail :luhuanliang @tsinghua.org. cn ;

3 Corresponding author 有毒重金属是城市生活垃圾焚烧过程中产生的 重要污染物之一 ,这些重金属容易富集在亚微米颗 粒上排入大气中 ,其中烟囱尾气中镉的排放浓度为 10~40 mg・ m -

3 ,从而给环境造成很大的危害 [1] . 现 代化大型垃圾焚烧厂主要采用向焚烧烟气中喷入活 性炭的方法来捕获重金属 ,但活性炭价格昂贵 ,且使 用量大 ,因此 ,开发廉价高效的非活性炭固体吸附剂 具有重要的现实意义. Uberoi 、 Chen 等人 [2~6] 研究发 现 ,主要成分为硅铝酸盐或者氧化钙的固体吸附剂 (如硅土、 高岭土、 石灰石和氧化铝等) 在高温下可以 吸附不同种类的重金属. 但上述研究仅局限于孔隙 结构并不发达的原土矿物. 王德荣、 程俊峰等 [7 ,8] 采 用碱性添加剂 (Na2 CO3 和NaOH 等) 改性冶金焦、 成 型焦和石灰类物质 ,结果表明 ,改性后的这些物质其 对酸性气体的净化效率得到大幅度地提高 ,但这些 工作并未验证其对烟气中重金属物质的吸附效果. 第25 卷第