基于含铬革屑制备吸附-降解型胶原/ZnO复合材料

Preparation of Adsorption-degradation Collagen/ZnO Composites Based on Chrome-tanned Leather Shavings

危险废弃物含铬革屑的资源化利用是制革行业面临的一大难题.含铬革屑的主要成分胶原可作为吸附材料,但存在稳定性差、需解吸等问题,限制了其在水处理领域的应用.本文通过酸法从含铬革屑中提取胶原纤维并原位负载纳米氧化锌(ZnO)制备了吸附-降解型胶原/ZnO复合材料.红外光谱及X射线衍射谱图显示,ZnO成功负载且呈片状,具有六角纤锌矿晶型,负载到胶原纤维上后并不会影响其自身的光响应范围,禁带宽度为3.20eV.当锌前驱体溶液浓度为0.12mol/L、胶原纤维分散液pH值为8、胶原海绵质量为60mg时,复合材料光催化性能最佳;在160min内对10mg/L亚甲基蓝(MB)的降解率达95.2%;循环5次后,降解率依然可达到87.5%.动力学模型拟合结果显示,复合材料对MB的吸附更符合拟二级吸附动力学模型,受化学吸附控制;MB的光催化降解过程符合一级降解动力学方程,降解速率最高为0.0172min^(-1).此外,ZnO的引入提高了复合材料的抗菌性和热稳定性.

The utilization of hazardous waste chrome-tanned leather shavings is a difficult problem in the leather industry.Collagen,the main component of chrome-tanned leather shavings,can be used as adsorbent material;however,its application in the wastewater treatment field is limited due to the low stability and subsequent desorption challenges.In this paper,adsorption-degradation collagen/ZnO composites were prepared by in-situ loading of zinc oxide nanoparticles(ZnO)on collagen fibrils extracted from chrome-tanned leather shavings via acid methods.The infrared and X-ray diffraction spectra showed that ZnO with sheet hexagonal wurtzite structure was successfully loaded;meanwhile,its own photoresponse range was unaffected and the forbidden bandwidth was 3.20 eV.When the concentration of zinc precursor solution was 0.12 mol/L,the pH value of collagen fibril dispersion liquid was 8 and the mass of collagen sponge was 60 mg,the photocatalytic degradation of the composite was the best;namely,the degradation ratio of 10 mg/L methylene blue(MB)reached 95.2%within 160 min and still reached 87.5%after five cycles.The fitting results of the kinetic models showed that the adsorption of MB by the composites was according with the pseudo-second-order adsorption kinetic model,which was controlled by chemisorption;moreover,the photo-catalytic degradation of MB obeyed the first-order degradation kinetic model,and the highest degradation rate was 0.0172 min-1.Additionally,the introduction of ZnO enhanced the antimicrobial property and thermal stability of the collagen/ZnO composites.