生物质炭/TiO_(2)复合材料去除偶氮染料的研究进展

Research progress on removal of azo dyes by biochar/TiO_(2) composites

偶氮染料被认为是工业生产中使用最广泛的合成染料,其化学惰性较高,产生的废水成分较为复杂,比天然染料更加难以通过物理和化学等方法进行脱色。偶氮染料及其降解产物有较强的生物毒害性,大量排放会对环境造成严重危害。在众多染料废水的处理技术中,吸附和光催化协同是一种先进的废水处理手段,具有高效、节能、环保及成本低廉等优点,是现阶段环境修复领域的研究热点。光催化材料的催化活性主要取决于材料的带隙宽度、比表面积和电子-空穴对的产生。吸附材料生物质炭具有丰富的表面官能团和大的比表面积,可增加TiO_(2)等光催化剂与污染物的接触,提高降解效率。同时基团的掺杂可以降低催化剂带隙宽度,延长光生载流子的寿命,有效提高光催化活性;而光催化可以降解附着的污染物,使生物质炭恢复吸附能力,达到回收再利用的效果。通过利用生物质炭/TiO_(2)复合材料,不仅可以实现“吸附+光催化”同步去除偶氮染料的效果,而且复合材料的协同作用还可以弥补两种处理方法的不足。综述了生物质炭和TiO_(2)分别用来处理偶氮染料的研究现状并分析了不足之处,概括了生物质炭/TiO_(2)复合材料的制备方法及去除偶氮染料的协同作用机理,最后对生物质炭/TiO_(2)复合材料用于偶氮染料废水处理的现状和未来发展进行了总结与展望。

Azo dyes are considered the most widely consumed synthetic dyes in industrial activities,which have high chemical inertness and produce dye wastewater of various components.So,the conventional physical and chemical methods adopted to degrade azo dye effluents are not always efficient compared with natural dyes.Azo dyes and their degradation products are biological toxicity,and their emissions will also cause serious harm to the environment.The adsorption and photocatalytic synergy are an advanced wastewater treatment method with highefficiency,energy-saving,environmentally friendly and low-cost advantages among many dye wastewater treatment technologies.This method become a research hotspot in the field of environmental remediation.Moreover,the photocatalytic activity of the photocatalytic materials mainly depends on the bandgap,surface area,and generation of electron-hole pairs.Biochar as an adsorbent has abundant surface functional groups and large specific surface area,increasing the contact area of photocatalyst TiO_(2) and pollutants,thus improving degradation efficiency.In addition,the doping of functional groups can reduce the bandgap energy of TiO_(2),and promote the generation of electron-hole pairs,which improve the photocatalytic activity.Meanwhile,the photocatalytic degradation can restore the adsorption capacity and achieve the effect of recycling.The simultaneous removal of azo dye by“adsorption+photocatalysis”can be achieved using the biochar/TiO_(2) composite material.The synergistic effect can make up for the deficiency of the two treatment methods.Thus,the research status of biochar and TiO2 respectively for azo dyes wastewater treatment were discussed,while the shortcomings of the present research were analyzed in present review.Then,the preparation methods of biochar/TiO_(2) composites and the primary mechanism of synergetic effect during azo dyes removal were summarized.Furthermore,the current status and future development of TiO_(2) composite materials for azo dye wastewater treatment were also be summarized.