共查询到18条相似文献,搜索用时 187 毫秒
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分析废退锡液不稳定的根本原因,通过考察硝酸浓度对溶液氧化性的影响及Cl^-、甲基烷基磺酸对Sn^2+的稳定作用,来寻找使废退锡液稳定的因素。 相似文献
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水质中总氮超标会严重污染生态环境,危害人体健康。印制线路板行业废水中一般含有较高的总氮,生产过程产生的的硝酸型退锡废水是其总氮的典型来源之一。针对硝酸型退锡废水,为解决金属离子含量和总氮高的问题,采用源头控制,利用化学沉淀法和生物脱氮法,研究了沉淀pH、碳源种类、停留时间、溶解氧等对金属离子和总氮去除效果的影响。研究结果表明,在化学沉淀pH为10、生化进水pH 7.5~8.5、生化停留时间48 h、乙酸钠作为碳源、溶解氧0.2~0.3 mg/L的条件下,采用该方法可以去除退锡废水中99.9%的重金属,总氮去除率在98.5%以上。 相似文献
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PCB退锡废水含大量锡、铜、铁等重金属以及硝酸等有机、无机酸,具有强腐蚀性,是多年来严重污染环境的废水之一,本文设计了一种硝酸型PCB退锡废水综合回收利用工艺,研究了相关工艺参数对该类废水中主要成分锡的回收率的影响。实验结果表明:锡与碱用量为1∶4(mol/mol),反应温度在98~105℃,反应时间为80 min时,锡的转化率、回收率最高可达98.5%以上。 相似文献
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以硫醇甲基锡废底料为研究对象,通过元素组成和XRD分析,结合废底料物性特征,设计了微波辅助干馏回收低沸点物质,残渣脱氯后用作锡冶炼精料的基本构思。实验研究表明:干馏可回收质量分数约15.86%的低沸点物质,同时可脱除约31.06%的氯。以残渣中氯含量为考察指标,系统研究了残渣与过氧化氢液固比、氧化静置时间、残渣与浓硫酸液固比、微波强化时间对氯脱除率的影响,结果表明:过氧化氢与残渣液固比为1∶5、氧化静置时间为30min、浓硫酸与残渣液固比为1∶3、微波强化时间为80min时,残渣中氯质量分数为0.59%,氯的脱除率可达到97.48%,满足企业锡冶炼精料氯质量分数<0.8%要求。通过对微波浸取机制讨论以及残渣XRD、SEM的表征,初步对干馏残渣脱氯过程进行了机理分析,为硫醇甲基锡废底料中氯的脱除提供了理论依据,研究成果具有较好的应用前景。 相似文献
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以碱处理β沸石作为硅铝源,以CTAB为模板剂,合成了β/MCM-41介孔-微孔复合分子筛,以其为载体制备Pd-β/MCM-41复合分子筛催化剂,利用XRD、N2吸附-脱附、NH3-TPD和XRF等技术对其进行了表征,并与γ-Al2O3、USY、ZSM-5等载体制备的催化剂比较了废食用油加氢裂解活性。结果表明:β/MCM-41复合分子筛同时具备β沸石和MCM-41分子筛的结构,β/MCM-41为载体时,Pd-β/MCM-41催化剂具有适宜的中强酸性中心,适宜的孔道分布结构,催化剂加氢裂解废食用油的活性最高。此外还考察了催化剂制备条件对废食用油加氢裂解反应的影响,结果表明:采用离子交换法制备负载量2%的Pd-β/MCM-41复合分子筛催化剂、焙烧温度为500 ℃时,催化剂对废食用油加氢裂解的效果最好。此时,原料油的转化率可以达到85.9%,生物汽油的收率可以达到16.4%,生物柴油的收率达到17.8%,且此催化剂水热稳定性较好,再生性能良好,工业化应用前景较好。 相似文献
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溶剂萃取法是盐湖提锂的重要工艺方法。采用磷酸三丁酯(TBP)/1-丁基-3-甲基咪唑双三氟甲基磺酰亚胺盐([C4mim][NTf2])离子液体体系对高镁锂比盐湖卤水中的锂进行萃取分离提取实验,对负载有机相的洗涤和反萃过程进行了研究。萃取实验:在TBP与[C4mim][NTf2]体积比为9∶1、相比(有机相与水相的体积比)为2∶1条件下,锂离子与其他离子的分离系数分别为β(锂/钠)=94.70、β(锂/钾)=148.85、β(锂/镁)=131.81。洗涤实验:系统考察了洗涤剂种类及浓度、相比、洗涤次数等因素对杂质离子洗脱率的影响,结果发现氯化锂和盐酸的混合溶液是从负载有机相中洗涤除去杂质离子的有效洗涤剂。洗涤过程适宜条件:洗涤剂中氯化锂浓度为4 mol/L、盐酸浓度为0.5 mol/L,相比为5∶1,洗涤次数为2次。反萃实验:用稀盐酸(1.0 mol/L)对负载有机相进行反萃取,在相比为1∶1条件下,单级反萃率达到97.81%。研究表明,离子液体体系作为一种新型萃取体系,在高镁锂比盐湖卤水中提取锂具有较好的应用前景。 相似文献
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同时应用超重力精馏连续与间歇操作分离回收果胶沉淀溶剂中的乙醇,并以不锈钢波纹丝网为填料,在原料乙醇质量分数xf=55%、回流比R=4、超重力因子β=63.16~252.67、原料流量F=15~50L/h、1.01×105Pa和室温进料下操作,研究了四级超重机在连续精馏过程中的传质性能;并在β=161.71、R=2.5~7及1.01×105Pa操作条件下,考察了间歇精馏过程中不同回流比R对塔顶和塔底乙醇浓度xd和xw的影响.结果表明,在连续精馏过程中,理论塔板数NT随β和F的增大而增加,设备的等板高度HETP为41.12~58.21mm,xd=93%,xw=35%;在间歇精馏过程中,xd随着R的增大先增高后降低,xw随着R和t的增大而下降,所得产品xd为92.5%,xw为1.05%;乙醇分离回收效果良好,回收率为91.28%,单位回收乙醇产品成本为0.644元/L,充分表现出超重力精馏工艺应用于果胶沉淀溶剂的回收再利用的优势. 相似文献
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石化医药行业会产生大量乙腈废液,通过无机分子筛膜分离技术进行回收可以创造可观的经济价值。然而,乙腈废液水含量较高,并且具有一定的酸性,目前应用比较广泛的NaA型分子筛膜不能在该体系下长期使用。使用自制的平均粒径为600 nm的T型分子筛作为晶种,采用真空涂敷法将晶种负载在α-Al2O3载体管表面,在150 ℃下水热晶化16 h制备出T型分子筛膜,并对其做膜性能评价实验。结果表明,自制的T型分子筛膜在进料流量为3.5 L/h、温度为100 ℃条件下对含有1%(质量分数)乙酸和10%水(质量分数)的乙腈混合溶液进行膜分离脱水实验,渗透通量为2.51 kg/(m 2·h);在120 h长时间运行过程中,分离系数保持在2 250以上,T型分子筛膜性能基本保持不变。 相似文献
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The performance of a rotating packed bed (RPter solutioB) with three kinds of packings was investigated using alcohol/wan under continuous distillation conditions at atmospheric pressure. The effects of average high gravity factor (β), reflux ratio (R), and feedstock flux (F) on mass-transfer in distillation were examined separately. Experimental results indicated that the total number of theoretical units (NTU) of RPB increased with β, R, and F.Of the three kinds of packings, the wave thread packing of stainless steel (Packing-Ⅲ)-had the best mass transfer efficiency with the height equivalent of a theoretical plate (HETP) of approximately 7.35 mm- 23.58 ram, whereas the corrugated disk pacing of stainless steel,(Packing Ⅰ) had the worst one with the HETP of about 13.4 mm-48.07 mm.Correlations were cleveloped to describe the mass transfer efficiency for packings Comparing.experimental data with the data calculated by correlation, the average deviate obtained for each packing was 0.72%, 1.98%, and 2.7%, respectively, implying that the accuracy of correlations developed was reasonable. 相似文献
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Rongling LIU Yingjie QIN Xiaojun LI Liqiang LIU 《Frontiers of Chemical Science and Engineering》2012,6(3):311
Multiple-effect membrane distillation (MEMD) using a hollow fiber-based air-gap membrane distillation module was experimentally examined for concentrating dilute aqueous hydrochloric acid. The effects of the hot and cold feed-in temperatures, and the feed-in volumetric flow rates on the performance of the MEMD process were studied. The performance was evaluated using the performance ratio (PR ), the average selectivity of water over HCl (β avg) and the permeation flux (N ). Two types of porous fibers made from polypropylene were used to fabricate the MEMD modules. The experimental data indicated that hollow fibers with high porosity were preferred for the MEMD process. The PR , β avg and N all decreased as the feed concentration increased. When the feed concentration was below 12 wt-%, the PR was 6.0 – 9.6 and β avg was 10 – 190. When the concentration of HCl reached 18 wt-%, the PR and β avg were about 4.4 and 2.3, respectively. However, β avg sharply decreased to around 1.0 when the feed was further concentrated. During an operational stability test that lasted for 30 days, the performance of the MEMD modules remained good. 相似文献
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考察了成型时拟薄水铝石和合金粉的比例、胶溶剂硝酸质量分数,水粉比及焙烧温度对骨架镍催化剂侧压强度的影响,采用XRD和TG-DTA等手段对催化剂进行表征。结果表明,催化剂侧压强度随着拟薄水铝石和合金粉的比例、胶溶剂硝酸质量分数、水粉比以及焙烧温度的提高呈现先增加后减小的规律,在拟薄水铝石与合金粉质量比1.5、胶溶剂硝酸质量分数6%和水粉比0.21 mL.g-1条件下成型,860℃空气中焙烧,得到侧压强度最好的催化剂,以苯乙烯、甲基苯乙烯加氢为探针反应,对催化剂的加氢性能进行评价,结果表明,在反应压力2 MPa、温度80℃、原料空速2 h-1和V(H2)∶V(油)=300∶1条件下,苯乙烯与甲基苯乙烯在考察的500 h运转周期内,转化率接近100%,且催化剂活性保持稳定。 相似文献
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A novel disphase supplying supported liquid membrane(DSSLM),containing supplying feed phase and supplying stripping phase for transport behavior of Ni(II),have been studied.The supplying supported feed phase included feed solution and di(2-ethyhexyl) phosphoric acid(HDEHP) as the carrier in kerosene,and supplying stripping phase included HDEHP as the carrier in kerosene and HCl as the stripping agent.The effects of volume ratio of membrane solution to feed solution(O/F),pH,initial concentration of Ni(II) and ionic strength in the feed solution,volume ratio of membrane solution to stripping solution(O/S),concentration of H2SO4 solution,HDEHP concentration in the supplying stripping phase on transport of Ni(II),the advantages of DSSLM compared to the traditional supported liquid membrane(SLM),the system stability,the reuse of membrane solution and the reten-tion of membrane phase were studied.Experimental results indicated that the optimum transport of Ni(II) was ob-tained when H2SO4 concentration was 2.00 mol·L-1,HDEHP concentration was 0.120 mol·L-1,and O/S was 4:1 in the supplying stripping phase,O/F was 1︰10 and pH was 5.20 in the supplying feed phase.The ionic strength in supplying feed phase had no obvious effect on transport of Ni(II).When initial Ni(II) concentration was 2.00×10?4 mol/L,the transport percentage of Ni(II) was up to 93.1 % in 250 min.The kinetic equation was deduced in terms of the law of mass diffusion and the interface chemistry. 相似文献