污泥源腐殖酸的提取及沉淀低浓度稀土作用机制  

Extraction of humic acid derived from sludge and mechanism of low concentration rare earth precipitation

作　　者：麻欣宇 李雪蓉 叶松 王俊峰[1,2] 陈云嫩[1,2] 钟常明[1,2] MA Xinyu;LI Xuerong;YE Song;WANG Junfeng;CHEN Yunnen;ZHONG Changming(School of Resources and Environmental Engineering,Jiangxi University of Science and Technology,Ganzhou 341000,Jiangxi,China;Jiangxi Provincial Key Laboratory of Environmental Pollution Control forMining and Metallurgy,Jiangxi University of Science and Technology,Ganzhou 341000,Jiangxi,China)

机构地区：[1]江西理工大学,资源与环境工程学院,江西赣州341000 [2]江西理工大学江西省矿冶环境污染控制重点实验室,江西赣州341000

出　　处：《有色金属科学与工程》2023年第3期387-399,共13页Nonferrous Metals Science and Engineering

基　　金：江西省自然科学基金项目(20202BABL203039);国家重点研发计划“固废资源化”专项项目子课题(2018YFC1903401-3);国家自然科学基金项目(21866014);赣州市科技计划后补项目(赣市科发[2019]60号-54)。

摘　　要：采用焦磷酸钠法和碱溶酸析法分别从剩余污泥中提取污泥源腐殖酸。利用扫描电镜、红外光谱和三维荧光光谱对2种腐殖酸进行表征分析,并对比了二者对低浓度稀土离子的沉淀效果。结果表明:2种腐殖酸中均含有大量的羧酸类、胺类、羟基类官能团,但焦磷酸钠法提取的S-HA-1中官能团的种类更多、含量更高;当沉淀稀土离子浓度为103.40 mg/L时,2种腐殖酸对稀土的沉淀率分别达97.30%和91.18%,沉淀物中稀土元素重量百分比总和分别为31.73%和28.64%,S-HA-1沉淀效果较优。采用S-HA-1为沉淀剂,稀土离子浓度为51.70 mg/L时,通过单因素实验与响应面优化实验确定了较优反应条件:腐殖酸浓度0.25 g/L,反应时间56.53 min,搅拌速率106.27 r/min,反应温度40℃,pH=5.90,在此条件下,稀土沉淀率≥98%。利用能谱和红外光谱分析稀土沉淀物发现,沉淀过程中稀土离子与S-HA表面的酚羟基和羧基等官能团发生了一系列物理化学反应,形成腐殖酸-稀土絮状体沉淀。研究结果表明,从剩余污泥提取腐殖酸低浓度稀土离子沉淀剂,既能实现沉淀剂再利用,又能回收稀土资源。Extracted from surplus sludge by the sodium pyrophosphate and alkaline solution-acid extraction methods,respectively,sludge-derived humic acids were characterized by scanning electron microscopy,infrared spectroscopy and three-dimensional fluorescence.The precipitation effect of the two humic acids on the low concentration of rare earth ions was also compared.The results show that both humic acids contain a large amount of carboxylic acids,amines and hydroxyl groups,but the types and contents of functional groups are higher in S-HA-1 extracted by the sodium pyrophosphate method.When the rare earth ion concentration is 103.40 mg/L,the precipitation rates of rare earth elements are 97.30%and 91.18%,and the total weight percentages of rare earth elements in the sediment are 31.73%and 28.64%,respectively,with the best precipitation effec of S-HA-1.With S-HA-1 as a precipitatant,determined by a single-factor experiment and response surface optimization experiment,the optimal reaction conditions are the rare earth ion concentration of 51.70 mg/L,humic acid concentration of 0.25 g/L,the reaction time of 56.53 min,the stirring rate of 106.27 r/min,the reaction temperature at 40℃,pH of 5.90,and the rare earth precipitation rate≥98%.The analysis of rare earth precipitates by energy spectrum and infrared spectrum revealed that a series of physical and chemical reactions occured between rare earth ions and functional groups such as phenolic hydroxyl groups and carboxyl groups on the surface of S-HA during precipitation,forming humic acid-rare earth flocculent precipitates.The results show that humic acids can be extracted from residual sludge to be the low-concentration rare earth ion precipitatants,which can not only achieve precipitant reuse,but also recover rare earth resources.

关 键 词：剩余污泥 腐殖酸 低浓度稀土 沉淀 响应面优化 

分 类 号：TD955[矿业工程—选矿]