首页|Ti-Al水滑石的制备及吸附水中低质量浓度F-性能

Ti-Al水滑石的制备及吸附水中低质量浓度F-性能

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以AlCl3·6H2O和TiCl3为原料、NaOH为沉淀剂,采用共沉淀法制备了不同n(Ti)∶n(Al)的双金属氢氧化物(Ti-Al LDHs),考察了其对模拟废水中低质量浓度F-的吸附性能.采用SEM、BET和XRD对Ti-Al LDHs吸附F-前后的样品进行了表征,探究了Ti-Al LDHs的投加量、初始溶液pH对Ti-Al LDHs除氟容量的影响,测试了其循环再生能力.对Ti-Al LDHs吸附F-的机理进行了推测.结果表明,Ti-Al LDHs稳定性较好,呈现层状结构且均匀堆积,主要以分散的无定形态存在,具有较宽的孔径分布和较大的比表面积(108.34 m2/g);当n(Ti)∶n(Al)=2∶8、介质pH=6时制备的Ti-Al LDHs-1对F-具有最佳的吸附性能,在Ti-Al LDHs-1投加量为0.1 g/L、25℃、200 r/min、水浴恒温振荡12 h的条件下,Ti-Al LDHs-1的除氟容量最高,为63.08 mg/g;常温下,初始溶液pH=4时,投加量0.2 g/L的Ti-Al LDHs-1平衡除氟容量为47.59 mg/g,F-去除率为86.53%;共存阴离子(0~10 mmol/L)对F-吸附的影响高低排序为HCO3->CO32->SO42->H2PO4->Cl->NO3-.Ti-Al LDHs-1对F-的吸附更符合拟二级动力学模型(R2>0.99),吸附等温线更符合Langmuir模型.经过4 次吸附-解吸循环后,Ti-Al LDHs-1除氟容量仍可达初始的73%.吸附过程为离子交换、静电吸引和表面络合3种类型共同作用.
Preparation of Ti-Al hydrotalcite and its adsorption performance for F-with low mass concentration in water
Bimetallic hydroxides(Ti-Al LDHs)with different n(Ti)∶n(Al)were prepared by co-precipitation method using AlCl3·6H2O and TiCl3 as raw materials and NaOH as precipitant.The adsorption performance of Ti-Al LDHS for F-with low mass concentration in simulated wastewater were analyzed,and the Ti-Al LDHs samples before and after F-adsorption were characterized by SEM,BET and XRD.The effects of Ti-Al LDHs dosage and initial solution pH on the fluorine removal capacity of Ti-Al LDHs were investigated,while the recycling capacity of Ti-Al LDHS was analyzed.The F-adsorption mechanism by Ti-Al LDHs was further speculated.The results showed that Ti-Al LDHs displayed good stability,having a uniform stacking of laminar structure,and mainly existing in dispersed amorphous form with a wide pore size distribution and a large specific surface area(108.34 m2/g).Ti-Al LDHs-1 prepared from n(Ti)∶n(Al)=2∶8 and medium pH=6 exhibited the best F-adsorption performance,and the highest fluorine removal capacity reached 63.08 mg/g with the Ti-Al LDHs-1 dosage of 0.1 g/L,water-bath constant-temperature at 25℃at a shaking speed of 200 r/min for 12 h.At room temperature and the initial solution pH=4,the equilibrium fluorine removal capacity was 47.59 mg/g,while F-removal rate reached 86.53%with Ti-Al LDHs-1 dosage of 0.2 g/L.The influence of coexisting anions(0~10 mmol/L)on the adsorption of F-were as follows:HCO3->CO32->SO42->H2PO4->Cl->NO3-.The adsorption of F-by Ti-Al LDHs-1 was more consistent with the pseudo-second-order model(R2>0.99),and the adsorption isotherm was more consistent with the Langmuir model.After four adsorption-desorption cycles,the fluorine removal capacity of Ti-Al LDHs-1 could still reach 73%of the initial capacity.The adsorption process was controlled mainly by ion exchange,electrostatic attraction and surface complexation.

layered double hydroxidesco-precipitationadsorptionfluoride removalhydrotalciteswater treatment technology

陈彩虹、唐玉朝、伍昌年、黄显怀、朱静坤、张良霄

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安徽建筑大学 环境污染控制与废弃物资源化利用安徽省重点实验室,安徽 合肥 230601

合肥供水集团有限公司,安徽 合肥 230011

双金属氢氧化物 共沉淀法 吸附 除氟 水滑石 水处理技术

国家自然科学基金项目安徽省自然科学基金项目安徽省教育厅创新团队项目安徽省高校协同创新项目

523700012208085US202022AH010019GXXT-2023-046

2024

精细化工
大连化工研究院设计院 中国化工学会精细化工专业委员会 辽宁省化工研究院

精细化工

CSTPCD北大核心
影响因子:0.557
ISSN:1003-5214
年,卷(期):2024.41(8)
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