Application of 'waste' metal hydroxide sludge for adsorption of azo reactive dyes
Application of 'waste' metal hydroxide sludge for adsorption of azo reactive dyes
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DOI：
10.1016/s0043-1354(02)00375-5
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发表时间：
2003-02-01
期刊：
影响因子：
12.8
通讯作者：
Towprayoon, S
中科院分区：
文献类型：
--
作者：
Netpradit, S;Thiravetyan, P;Towprayoon, S
研究了金属氢氧化物污泥对偶氮活性染料的吸附性能，考察了染料投加量、体系pH值、吸附剂粒径、吸附剂投加量等因素对金属氢氧化物污泥去除偶氮活性染料的影响。使用的三种阴离子染料是CI活性红2、CI活性红120和CI活性红141，分别增加磺酸基的数量。只有0.2%（w/v）的粉末状污泥（< 75 μ m）在5分钟内从30 mg l（-1）活性染料溶液中去除颜色，而无需调节pH。染料的电荷量越大，在金属氢氧化物污泥上的吸附越大（> 90%）。体系pH值对金属氢氧化物的吸附和染料-金属络合物的形成起着重要作用。染料吸附的最佳体系pH为8-9，这接近于污泥的pH（zpc），而染料-金属络合物的沉淀发生在体系pH 2。污泥对活性染料的最大吸附量（Q度）为48-62 mg染料g（-1）吸附剂。Langmuir和Freundlich吸附模型表明，染料的电荷越大，吸附亲和力越强。由于吸附剂表面积的增加，较小的颗粒尺寸和较大的吸附剂量显示出更快的过程。脱附研究表明，金属氢氧化物污泥对磺化偶氮活性染料具有离子交换吸附的倾向。浸出数据表明，处理后的水是无毒的系统pH值大于5或溶液pH值大于2。(C)2002爱思唯尔科学有限公司版权所有。
The capacity and mechanism of metal hydroxide sludge in removing azo reactive dyes from aqueous solution was investigated with different parameters, such as charge amount of dyes, system pH, adsorbent particle size, and adsorbent dosage. The three anionic dyes used were CI Reactive Red 2, CI Reactive Red 120, and CI Reactive Red 141, increasing in number of sulfonic groups, respectively. Only 0.2%` (w/v) of powdered sludge (< 75 mum) achieved color removal from 30 mg l(-1) reactive dye solutions within 5min without pH adjustment. The larger the charge amount of the dyes, the greater the adsorption (> 90%) on the metal hydroxide sludge. The system pH played a significant role in the adsorption on metal hydroxides and formation of dye-metal complexes. The optimum system pH for dye adsorption was 8-9 which was close to the pH(zpc) of the sludge while the precipitation of dye-metal complexes occurred at system pH 2. The maximum adsorption capacity (Qdegrees) of the sludge for the reactive dyes was 48-62 mg dye g(-1) adsorbent. The Langmuir and Freundlich models showed that the higher charged dyes had a higher affinity of adsorption. The smaller particle size and the greater amount of adsorbent showed the faster process, due to an increase in surface area of adsorbent. Desorption studies elucidated that metal hydroxide sludge had a tendency for ion exchange adsorption of sulfonated azo reactive dyes. Leaching data showed that the treated water was nontoxic at a system pH above 5 or a solution pH above 2. (C) 2002 Elsevier science Ltd. All rights reserved.