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酸性沉淀法测定腐殖酸尿素中缩二脲含量的研究
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作者 段毅平 《山西化工》 2020年第1期38-39,53,共3页
根据腐殖酸是一种亲水的可逆胶体的特性,在腐殖酸尿素溶液中加入1 mol/L的H2 SO4溶液,调整试样溶液的pH值至1~2,使其中的腐殖酸产生凝聚作用,产生的絮凝物经中速滤纸过滤后,用分管光光度法测定缩二脲含量.实验过程简单快速,加标回收实... 根据腐殖酸是一种亲水的可逆胶体的特性,在腐殖酸尿素溶液中加入1 mol/L的H2 SO4溶液,调整试样溶液的pH值至1~2,使其中的腐殖酸产生凝聚作用,产生的絮凝物经中速滤纸过滤后,用分管光光度法测定缩二脲含量.实验过程简单快速,加标回收实验回收率在99.8%~101.2%,取得满意效果. 展开更多
关键词 腐殖酸尿素 酸性沉淀 缩二脲
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酸性铵盐沉钒条件实验研究 被引量:25
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作者 李大标 《过程工程学报》 CAS CSCD 北大核心 2003年第1期53-56,共4页
以温度、时间、搅拌强度为变量,以沉淀率、抽滤后滤饼含水量、烘干后多钒酸铵(APV)中杂质含量等作为评价指标,对酸性铵盐沉钒条件进行了研究. 结果表明:以含钒30 g/L左右的溶液为原料,加硫酸铵后用硫酸调节pH至2.2左右,沸水浴(95oC)中沉... 以温度、时间、搅拌强度为变量,以沉淀率、抽滤后滤饼含水量、烘干后多钒酸铵(APV)中杂质含量等作为评价指标,对酸性铵盐沉钒条件进行了研究. 结果表明:以含钒30 g/L左右的溶液为原料,加硫酸铵后用硫酸调节pH至2.2左右,沸水浴(95oC)中沉淀120 min左右,桨式搅拌转速300 r/min,可获得99%以上的沉淀率,抽滤滤饼含水量20%以下,烘干后APV含Na 0.70%~1.08%, S 0.78%~1.20%. 展开更多
关键词 多钒酸铵 APV 酸性铵盐沉淀 工艺条件
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硫酸钾生产除铁工艺研究与应用
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作者 屠兰英 《青海大学学报(自然科学版)》 2004年第1期34-35,45,共3页
研究了硫酸钾生产中用空气氧化———酸性沉淀法除铁工艺,通过试验确定出了最佳工艺条件,将其应用于实际生产,溶液中铁含量可控制在0 01g/L以下。
关键词 硫酸钾 空气氧化 酸性沉淀 除铁工艺
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Synthesis of nickel ferrite precursors from low grade nickel matte 被引量:3
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作者 何利华 赵中伟 张有新 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第8期2422-2430,共9页
Fine nickel ferrite precursors NiFe2(C204)3·6H2O were obtained via co-precipitation method with low grade nickel matte as the raw material. Thermodynamic analysis of NiClz-FeC12-(NH4)2C204-H20 system for prec... Fine nickel ferrite precursors NiFe2(C204)3·6H2O were obtained via co-precipitation method with low grade nickel matte as the raw material. Thermodynamic analysis of NiClz-FeC12-(NH4)2C204-H20 system for precipitation identified that the theoretical optimum co-precipitation pH value is 2, and C2O2 has strong complexation with Ni2+ and Fe2+ ions. Based on these theoretical considerations, the effects of parameters on the precipitation rates and precursors size were investigated systematically. The results show that the optimum co-precipitation conditions are pH=2, temperature 45 ℃, 1.2 times theoretical amount of (NH4)2C204 dosage and 3% PEG400 addition. Under these conditions, the precipitation rates of Ni2+ and Fe2+ are both over 99.8%, with the precursors size of 1-2 urn. Furthermore, X-ray diffraction (XRD) and thermogravimetry-differential thermal analysis (TG-DTA) demonstrate that the precursors are single-phase solid solution, wherein the nickel/iron atoms are replaced by the iron/nickel atoms reciprocally. 展开更多
关键词 nickel ferrite FERRITE magnetic materials CO-PRECIPITATION low grade nickel matte
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Separation and recovery of copper in Cu-As-bearing copper electrorefining black slime by oxidation acid leaching and sulfide precipitation 被引量:8
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作者 Mei-qing SHI Xiao-bo MIN +4 位作者 Chen SHEN Li-yuan CHAI Yong KE Xu YAN Yan-jie LIANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2021年第4期1103-1112,共10页
A new hydrometallurgical route for separation and recovery of Cu from Cu-As-bearing copper electrorefining black slime was developed. The proposed process comprised oxidation acid leaching of Cu-As-bearing slime and s... A new hydrometallurgical route for separation and recovery of Cu from Cu-As-bearing copper electrorefining black slime was developed. The proposed process comprised oxidation acid leaching of Cu-As-bearing slime and selective sulfide precipitation of Cu from the leachate. The effects of various process parameters on the leaching and precipitation of Cu and As were investigated. At the first stage, Cu extraction of 95.2% and As extraction of 97.6% were obtained at 80 ℃ after 4 h with initial H2 SO4 concentration of 1.0 mol/L and liquid-to-solid ratio of 10 mL/g. In addition, the leaching kinetics of Cu and As was successfully reproduced by the Avrami model, and the apparent activation energies were found to be 33.6 and 35.1 kJ/mol for the Cu and As leaching reaction, respectively, suggesting a combination of chemical reaction and diffusion control. During the selective sulfide precipitation, about 99.4% Cu was recovered as CuS, while only 0.1% As was precipitated under the optimal conditions using sulfide-to-copper ratio of 2.4:1, time of 1.5 h and temperature of 25 ℃. 展开更多
关键词 copper electrorefining black slime oxidation acid leaching selective sulfide precipitation leaching kinetics copper recovery
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Production and characterization of alkaline extracellular lipase from newly isolated strain Aspergillus awamori HB-03 被引量:1
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作者 夏金兰 黄斌 +1 位作者 聂珍媛 王威 《Journal of Central South University》 SCIE EI CAS 2011年第5期1425-1433,共9页
A strain HB-03 to produce alkaline extracellular lipase was isolated from oil-rich soil samples and identified as Aspergillus awamori. The growth conditions and nutritional factors for lipase production by strain HB-0... A strain HB-03 to produce alkaline extracellular lipase was isolated from oil-rich soil samples and identified as Aspergillus awamori. The growth conditions and nutritional factors for lipase production by strain HB-03 were optimized, and the maximum lipase production of (45.9±2.3) U/mL was obtained at 30 ℃ and pH 7.0 after 36 h using olive oil (1%) and sucrose (0.5%) as carbon sources and combination of peptone (2%), yeast extract (0.5%) and ammonium sulfate (0.1%) as nitrogen sources. The lipase was purified to homogeneity with 10.6-fold, 18.84% yield and a specific activity of 1 862.2 U/mg using ammonium sulfate precipitation followed by SephadexG-75 gel filtration chromatography. The purified lipase with molecular mass of 68 ku was estimated by SDS-PAGE. The optimum pH and temperature for the purified lipase were found to be 8.5 and 40 ℃, respectively. The lipase kept more than 80% of activity in pH 7.0-10.0 and temperatures up to 45 ℃. The metal ions of Mn2+, Ba2+ significantly enhanced the lipase activity, whereas Cu2+, Fe3+ and Mg2+ strongly reduced the lipase activity. The Km and Vmax values of the purified enzyme for p-nitrophenyl palmitate were 0.13 mrnol/L and 60.6 mmol/(L.min), respectively. The results show that this novel lipase has potential industrial applications. 展开更多
关键词 alkaline lipase Aspergillus awamori PURIFICATION CHARACTERIZATION
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Comparative studies on the biochemical characteristics of natural actomyosin isolated from PSE and normal pork 被引量:2
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作者 丁玉庭 桑卫国 陈艳 《Journal of Zhejiang University Science》 EI CSCD 2004年第6期684-688,共5页
Biochemical changes of natural actomyosin from fresh pale, soft, exudative (PSE) and normal pork were studied,and the effects of different storage temperatures and different incubation temperature and times on sample ... Biochemical changes of natural actomyosin from fresh pale, soft, exudative (PSE) and normal pork were studied,and the effects of different storage temperatures and different incubation temperature and times on sample superprecipitation,total sulfhydryl (-SH) content, and ATP (adenosine triphosphate) sensitivity were investigated. The results demonstrated that ATPase activity and thermal stability of PSE actomyosin were lower than those of normal pork; and that PSE actomyosin had higher -SH content than that of normal pork at all incubation temperatures and times tested. 展开更多
关键词 PSE PORK ACTOMYOSIN Biochemical characteristics
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源自萨斯奎汉钠(美)河流域的河水中铝的物种形式
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作者 ShupingBi 葛秀珍 《水文地质工程地质技术方法动态》 2002年第1期16-16,共1页
关键词 酸性沉淀 物种形式 切萨皮克河湾 河水 流域
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杂质离子对沉淀多钒酸铵的影响 被引量:11
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作者 杨合 毛林强 +1 位作者 薛向欣 刘东 《钢铁钒钛》 CAS 北大核心 2013年第3期13-18,共6页
采用酸性铵盐法沉钒,研究了沉钒液中的杂质离子Cr、P、Si、Cl-、SO42-对钒沉淀的影响。结果表明:Cr浓度的增大能够显著降低钒的沉淀率,对低浓度的钒溶液影响更显著;Si对沉钒率影响较小,P对钒的沉淀率有较大影响,当P浓度大于0.1 g/L时,... 采用酸性铵盐法沉钒,研究了沉钒液中的杂质离子Cr、P、Si、Cl-、SO42-对钒沉淀的影响。结果表明:Cr浓度的增大能够显著降低钒的沉淀率,对低浓度的钒溶液影响更显著;Si对沉钒率影响较小,P对钒的沉淀率有较大影响,当P浓度大于0.1 g/L时,沉钒率在75%以下;Cl-在低浓度条件下对沉钒率影响不大,但当NaCl浓度大于100 g/L时,沉钒率低于20%;SO42-对沉钒率影响不显著。 展开更多
关键词 V2O5 酸性铵盐沉淀 多钒酸铵 杂质 沉钒率
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蛋白A亲和层析法纯化单克隆抗体工艺的优化 被引量:10
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作者 陈泉 卓燕玲 +6 位作者 许爱娜 咸漠 彭馨莹 杨元生 张海波 年锐 张巍 《生物工程学报》 CAS CSCD 北大核心 2016年第6期807-818,共12页
治疗性单克隆抗体药物已成为生物医药领域市场最主要的产品类别。蛋白A亲和层析作为第一步捕获抗体蛋白最为有效的手段仍然在现有单克隆抗体纯化平台中占据主导地位。在本研究中,首先开发了一种基于低p H处理抗体细胞回收液的新型细胞... 治疗性单克隆抗体药物已成为生物医药领域市场最主要的产品类别。蛋白A亲和层析作为第一步捕获抗体蛋白最为有效的手段仍然在现有单克隆抗体纯化平台中占据主导地位。在本研究中,首先开发了一种基于低p H处理抗体细胞回收液的新型细胞液回收技术,该技术能有效去除宿主相关污染物(非组蛋白宿主杂质蛋白、组蛋白、DNA、蛋白聚合物等),同时保证较高的抗体回收率。通过该技术有效预处理后,蛋白A纯化效率可提高10倍左右,并且有效避免了抗体洗脱液中和后浊度的上升,大大减轻了后续蛋白纯化的压力。同时我们也对酸性处理中各种宿主杂质去除机制进行了研究。然后,预处理的洗脱液再经一步Capto adhere色谱纯化,非组蛋白宿主杂质蛋白降低至5 ppm、DNA小于1 ppb、组蛋白降低至检测限以下、蛋白聚合物小于0.01%。总过程抗体蛋白收率87%。该两步法抗体纯化技术可有效集成至当前主流抗体纯化平台,具有良好的大规模应用价值。 展开更多
关键词 蛋白A 单克隆抗体 纯化 细胞回收液 酸性沉淀 宿主杂质蛋白 组蛋白 DNA
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An optimum route to prepare FePO_4 ·2H_2O and its use as an iron source to synthesize LiFePO_4
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作者 LI MingJuan SUN LiQun +2 位作者 SUN Kai WANG RongShun XIE HaiMing 《Science China Chemistry》 SCIE EI CAS 2013年第5期576-582,共7页
LiFePO4 cathode material is synthesized by a simple solid-state reaction method with FePO42H20 as iron source and citric acid as reductive agent and carbon source. This study examines the effects of different oxidatio... LiFePO4 cathode material is synthesized by a simple solid-state reaction method with FePO42H20 as iron source and citric acid as reductive agent and carbon source. This study examines the effects of different oxidation routes to prepare FePO4"2H20 on the electrochemical performance of as-synthesized LiFePO4. Iron phosphate was prepared by two routes from FeSO4'7H20. One is the formation of Fe3(PO4)2 precipitate in the first step and subsequent oxidation to FePO4 precipitate. The other is the oxidation of ferrous to ferric ion firstly, and then to form FePO4 precipitate directly. The results indicate that substantial differences in the structure and electrochemical properties of LiFePO4 depend on the behavior of FePO4. Iron phosphate obtained through one step precipitation has a smaller particle size and more uniform particle distribution, which is demonstrated to be more applicable as the iron source to synthesize LiFePO4/C. As-prepared LiFePO4/C shows an excellent rate capability and cycle performance. The initial discharge capacities of 160.6 mAh/g and 107 mAh/g are achieved at 0.1 C and 10 C, respectively. The good capacity retention of 97% after 300 cycles is maintained at the rate of 5 C. 展开更多
关键词 lithium ion batteries cathode LIFEPO4 FePO4 ·2H2O ectrochemical property
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One enantiomeric fluorescent sensor pair to discriminate four stereoisomers of threonines
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《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2013年第3期301-306,共6页
The BINOL-amino alcohol enantiomeric pair (S)-I and (R)-I are discovered to conduct both enantioselective and diastereose- lective fluorescent discrimination of the four stereoisomers of threonine derivatives. Thi... The BINOL-amino alcohol enantiomeric pair (S)-I and (R)-I are discovered to conduct both enantioselective and diastereose- lective fluorescent discrimination of the four stereoisomers of threonine derivatives. This study utilizes different fluorescence responses of one sensor at two emission wavelengths toward the stereoisomeric substrates which expands the capability of the sensor in chiral recognition. In addition, the sensor pair also allows visual recognition of the N-protected L-allo-threonine and D-allo-threonine by enantioselective precipitation. 展开更多
关键词 fluorescent sensor ENANTIOSELECTIVE DIASTEREOSELECTIVE amino acid THREONINE BINOL
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