生物纳米铁/铈联用过碳酸钠改善污泥脱水性能

The improvement of sludge dewaterability by bio-iron/cerium nanoparticles combined with sodium percarbonate

采用葡萄皮渣多酚提取液、亚铁盐和三价铈盐制得生物纳米铁/铈(Fe/Ce-NPs),联用过碳酸钠(SPC)对活性污泥进行调理.优化条件下:铁铈摩尔比4:1、投加30mgFe/Ce-NPs/g·TSS、200mgSPC/g·TSS、pH3、反应30min,污泥比阻(SRF)、过滤时间(TTF)和泥饼含水率(Wc)分别由9.74×10^(13)m/kg、92s和80.5%降至2.67×10^(13)m/kg、42s和71.2%.进一步联用聚丙烯酰胺(PAM),Wc降至65.8%;初始pH6时,调理后的污泥pH7.1(后续可免去pH值调节)且仍保持良好脱水性能.类芬顿(Fe/Ce-NPs+SPC)反应中,铁铈间的电子传递促使⋅OH产生量大幅提高(比传统芬顿提高0.9倍),Zeta电位绝对值大大降低(由-17.5~-4.6mV).三维荧光光谱(3D-EEM)与FTIR表征分析显示:Fe/Ce-NPs+SPC氧化能够断裂维持α-螺旋的氢键,改变蛋白质二级结构的构象,导致蛋白质结构更加松散,促进污泥中更多结合水的释放.与芬顿法(Fe^(2+)/H_(2)O_(2))和(Fe^(2+)/SPC)比较,类芬顿体系(Fe/Ce-NPs+SPC)能够显著提高污泥脱水性能,尤其是近中性pH6下调理污泥,可以大大减少酸碱投加量.研究表明类芬顿体系(Fe/Ce-NPs+SPC)是一种新型环境友好的、高效强化污泥脱水的实用技术.

Bio-Fe/Ce-nanoparticles(Fe/Ce-NPs)prepared from grape-peel-seed extracts,Fe^(2+)and Ce^(3+)salts,were combined with sodium percarbonate(SPC)for activated sludge conditioning.Under the optimum conditions(molar ratio of iron to cerium 4:1,Fe/Ce-NPS dosage 30mg/g·TSS,SPC dosage 200mg/g·TSS,pH3 and 30min reaction),the specific resistance to filtration(SRF),Time to filtration(TTF)and water content of mud cake was reduced from 9.74×10^(13)m/kg,92s and 80.5%to 2.67×10^(13)m/kg,42s and 71.2%,respectively.Then,the water content can be further reduced to 65.8%with the combination of polyacrylamide(PAM).When at initial pH 6,the pH value of sludge after conditioning is 7.1(free from subsequent adjusting pH to neutral),and the conditioned sludge still maintain good dewaterability.During the Fenton-like reaction(Fe/Ce-NPs+SPC),electron transfer between Fe and Ce promoted the production of·OH greatly(0.9 times higher than the traditional Fenton reaction)and reduced the absolute value of Zeta potential drastically(from-17.5mV of raw sludge to-4.6mV after pretreatment).Three-dimensional fluorescence spectrum(3D-EEM)and FTIR characterization showed that Fe/Ce-NPs+SPC oxidation could interrupt the hydrogen bonds maintainingα-Helical and change the conformation of the secondary structure of extracellular protein,causing the looser protein structure,the more bound water in the sludge flocs releasing.Compared with Fenton systems(Fe^(2+)/H_(2)O_(2))and(Fe^(2+)/SPC),sludge dewaterability could be improved distinctly by Fenton-like system(Fe/Ce-NPs+SPC),especially conditioning sludge at near-neutral pH 6 with great reduction of acid-base dosage.Hence,Fe/Ce-NPs+SPC would be a new eco-friendly,efficient and practical technology for enhancing sludge dewaterability.