阴离子交换树脂吸附辣椒碱的动力学研究

以辣椒树脂为原料,采用静态吸附法确定了201×7型阴离子交换树脂吸附辣椒碱的最优工艺和提取机理。通过可见分光光度法测定了辣椒碱的质量浓度,并绘制出了不同pH的吸附等温线,建立了离子交换吸附辣椒碱的动力学模型。实验结果表明:该树脂吸附辣椒碱的最优pH值为5.5,当pH5.0或pH6.0时,Langmuir方程能够更好地拟合该吸附过程;而当pH=5.0~6.0时,辣椒碱的吸附等温线更符合Freundlich方程。在pH=5.5、308.15K下,较高的辣椒树脂的质量浓度能显著提高离子交换速率,且初期(t30 min)800~1200r/min的搅拌速率有利于吸附过程。通过计算得出,树脂吸附辣椒碱模型的速率常数k0=2.11×10-3s-1、活化能Ea=12.6 k J/mol、反应级数为0.268,并利用Freundlich模型解析获得了最优pH值(5.5)下阴离子交换树脂吸附辣椒碱的动力学方程。     

辣椒碱的提取精制和应用现状

综述了辣椒碱的性质、提取方法及用途。列举了溶剂萃取法、微波法和超临界CO₂流体萃取等典型的提取精制方法,并简要介绍了辣椒碱的应用前景。     

高良姜-香附提取纯化工艺的研究

采用L₉(3⁴)正交试验法，以醇浓度、料液比、提取时间、提取次数为影响因素，以出膏率和7个成分的含量为评价指标；考察大孔吸附树脂类型、上样醇浓度、最大上样量、上样流速、洗脱醇浓度，进行验证实验。确定高良姜-香附最优提取工艺为：70%乙醇，料液比1∶8,提取2次，每次2 h;纯化工艺：40%醇浓度上样液通过AB-8型树脂柱，生药量：树脂量=1∶2.4,上样流速2 BV·h^-1,80%乙醇洗脱。该提取纯化工艺条件合理，稳定可行，可为高良姜香附的开发利用提供基础。     

钩藤碱在离子交换纤维上的吸附动力学研究

采用静态吸附法考察钩藤碱在离子交换纤维上的吸附行为,并研究离子交换纤维对钩藤碱的吸附动力学。结果表明,钩藤碱在离子交换纤维上的吸附过程更好的符合Ho and McKay二级动力学方程,在吸附液初始浓度为100 mg/L,吸附温度323 K的条件下,二级动力学方程为t/q_t=0.001 2 t+0.006 5(R²=0.998);表观吸附活化能E_a为7.003 kJ/mol;速度控制步骤为液膜扩散控制,在吸附液初始浓度为60 mg/L,吸附温度303 K条件下,液膜扩散模型方程为-ln(1-q_t/q_e)=0.119 3 t(R²=0.998)。阳离子交换纤维可以吸附钩藤碱,并且具有良好的吸附性能。     

酸碱催化剂浓度对柔性硅气凝胶性能和结构的影响

以甲基三甲氧基硅烷(MTMS)和正硅酸乙酯(TEOS)作为混合硅源,甲醇为溶剂,十六烷基三甲基溴化铵(CTAB)为表面活性剂,通过酸碱两步催化溶胶凝胶法制备醇凝胶,经超临界干燥可以制备高弹性疏水块状硅气凝胶。分别采用0.1 mol·L^-1 和0.01 mol·L^-1 的草酸作为酸催化剂,5 mol·L^-1 和10 mol·L^-1 的氨水作为碱催化剂,研究不同酸碱催化剂浓度对其网络结构的影响。发现高浓度酸和高浓度碱以及低浓度酸和低浓度碱作为催化剂合成的硅气凝胶的网络结构更加均匀,孔径分布更窄。其中,在草酸浓度为0.01 mol·L^-1、氨水浓度为5mol·L^-1 时,所得硅气凝胶密度为0.135 g·cm^-3、比表面积为807 m²·g^-1、孔隙率约为93%,凝胶最大可压缩至其起始长度的60%,压缩回弹率为100%。     

无氟无铵铝合金表面预处理新工艺

针对铝合金表面预处理过程存在污染严重、水耗高等问题,研究开发无氟无铵铝合金表面预处理新工艺。考察了碱性药剂配方组成及浓度、温度和时间对铝耗和铝合金表面形貌的影响,并通过正交实验确定了新工艺的优化方案。研究结果表明,经过“预处理-中和”两个步骤,铝合金表面平整、起砂细腻,铝耗仅为 2.0%。新工艺起砂效果优于传统碱蚀工艺,与传统酸蚀工艺细腻砂面相近。新工艺铝耗比传统碱蚀工艺降低约71%,与传统酸蚀工艺相近。新工艺操作时间比传统碱蚀工艺和酸蚀工艺分别缩短了23%和31%。最佳药剂配方为Na₂CO₃（80 g·L^-1）, NaOH（8 g·L^-1）,Na₂SO₄（25 g·L^-1）, Na₃PO₄（20 g·L^-1）, SDS（0.6 g·L^-1）, 甘油（5 g·L^-1）。 最佳操作条件为55℃和10 min。新工艺不仅从工艺源头消除了氟和氨氮污染,还实现了除油-起砂-去机械纹等多功能一体化集成。具有低污染、低铝耗、低水耗、短流程、高效率等优点,兼具环境友好和资源节约等优势。     

超声辅助双水相体系提取枳壳总黄酮及其抗氧化活性研究

采用超声辅助丙酮/NaH₂PO₄·2H₂O双水相体系提取枳壳总黄酮,通过单因素实验和正交实验优化提取工艺,并通过DPPH法和ABTS法评价枳壳总黄酮的体外抗氧化活性。结果表明,枳壳总黄酮的最佳提取工艺为：液料比60∶1(g∶g)、提取时间50 min、提取温度70℃、NaH₂PO₄·2H₂O质量分数23%、丙酮质量分数45%,在此条件下,枳壳总黄酮得率为75.90 mg·g^-1;枳壳总黄酮具有一定的抗氧化活性,浓度为800μg·mL^-1时,其对DPPH自由基的清除率为98.57%,IC₅₀值为48.96μg·mL^-1;浓度为3 000μg·mL^-1时,其对ABTS自由基的清除率为98.40%,IC₅₀值为207.71μg·mL^-1。     

铁皮石斛生物总碱提取纯化研究

文章采用纤维素酶法提取铁皮石斛中的生物总碱,用离子交换树脂对铁皮石斛生物总碱进行了初步纯化,采用正交试验法优选石斛总碱的纯化条件。实验结果表明,离子交换树脂法最佳纯化条件为:上样速度为10 mL/3 h,洗脱液(氨水)浓度为1 mol/L,洗脱速度为50 mL/4 h,生物总碱最佳收集段为洗脱液流出20~30 mL时。本工艺操作简便,成本较低,值得进一步深入研究。     

新疆白喉乌头中4种生物碱的分离鉴定及含量测定

采用硅胶柱层析、硅胶柱色谱法等手段对白喉乌头的95%乙醇提取物中的化学成分进行了分离纯化,通过¹HNMR、¹³CNMR对分离得到的4种生物碱的结构进行了鉴定,并采用HPLC法同时测定了其含量。结果表明,从白喉乌头的95%乙醇提取物中共分离得到4个二萜生物碱,分别鉴定为：8-去氧刺乌头碱、异刺乌头碱、高乌甲素、冉乌头碱,其中异刺乌头碱为首次从白喉乌头中分离得到;3批白喉乌头药材中8-去氧刺乌头碱、异刺乌头碱、高乌甲素、冉乌头碱的平均含量分别为0.026 mg·g^-1、0.124 mg·g^-1、1.143 mg·g^-1、0.561 mg·g^-1,其中高乌甲素的含量最高。     

生活污水在线监测仪器的混合式废液综合处理研究

以生活污水在线监测设备的混合式废液作为研究对象，其主要污染物为Hg²⁺、Cr³⁺、Ag⁺和Cr⁶⁺。对比两种不同序列组合工艺，根据混合式废液特点确定硫铁矿-海绵铁-活性炭-离子交换树脂为优选工艺序列。结果表明，经上述工艺处理后，废水中总Hg、总Ag、总Cr和Cr⁶⁺的去除率分别为99.99%、100%、99%和99.96%。该工艺在不同环境温度、不同废液浓度负荷的情况下，均满足《污水综合排放标准》(GB8978-1996)标准。相比常规工艺，该工艺投加药量大幅度减少，综合费用降低。     

杂质离子对MgCl2和CO2反应-萃取-醇析耦合过程的影响

通过反应-萃取-醇析耦合过程，将MgCl₂和CO₂制备成碳酸镁和氯化氢气体是盐湖老卤资源化利用的有效途径。系统地研究了老卤中Na⁺、K⁺、Ca²⁺对MgCl₂和CO₂反应-萃取-醇析耦合过程得到的固体产物晶型晶貌的影响。结果表明，Na⁺和K⁺对耦合过程的影响相似，固体产物均为高纯棒状三水碳酸镁（MgCO₃·3H₂O），且Na⁺和K⁺均能选择性吸附在MgCO₃·3H₂O晶体的轴面（101），阻碍该晶面的生长，使得棒状MgCO₃·3H₂O直径变小；Ca²⁺对反应-萃取-醇析耦合过程有不利的影响，由于CaCl2能参与反应，生成球状无定形纳米钙镁碳酸盐，使得三水碳酸镁纯度降低。     

Intensification of zirconium and hafnium separation through the hollow fiber renewal liquid membrane technique using synergistic mixture of TBP and Cyanex-272 as extractant

The novel synergistic mixture of TBP and Cyanex-272 is used as the extractant in the hollow fiber renewal liquid membrane(HFRLM) technique for Zr/Hf separation.The effects of the chemical and operational parameters such as HNO_3 concentration in the donor phase,NH4 F concentration in the acceptor phase,Cyanex-272 and TBP concentration in the liquid membrane phase,the lumen and shell side flow rates,and aqueous/organic volume ratio on the mass transfer and separation performance of HFRLM method were investigated.The obtained results reveal the intensification potential of proposed HFRLM technique for selective extraction of Zr over Hf with separation factor higher than 100.The HFRLM method provides two times higher mass transfer flux in comparison with hollow fiber supported liquid membrane(HFSLM).Also,the HFRLM method shows satisfactory stability for 700 min of continuous operation.The Zr ion transport through the LM phase follows the coupled co-transport mechanism and the diffusion in the renewal layer is recognized as the rate-controlling step in the HFRLM process.Moreover,the Zr mass transfer coefficient and molar flux in the HFRLM method are calculated in the range of 1×10~(-8)to 8.4×10~(-7) m·s~(-1) and 4.9×10~(-6) to 20.1×10~(-6) mol·m~(-2)·s~(-1),respectively.     

纳米腐殖酸基离子交换复合树脂动态吸附-脱附冶金镍镉废水

系统研究了纳米腐殖酸基离子交换复合树脂在多离子共存体系中对Ni²⁺/Cd²⁺的选择吸附性能。以此为基础,通过多柱串联、饱和吸附、洗脱液套用方法完成了对Ni²⁺、Cd²⁺冶金废水资源化治理研究,用扫描电镜(SEM)、红外光谱仪(FTIR)、热重分析仪(TG-DTA)、X射线光电子能谱仪(XPS)及N₂吸附-脱附分析仪(BET)等物理手段对复合树脂的微观形貌、化学结构、耐热性、元素组分变化及孔径分布进行表征。研究结果表明:纳米腐殖酸基复合树脂对Ni²⁺、Cd²⁺离子具有吸附速度快[0.55～1.50 mg·(g·min)^-1]、交换容量高(Ca²⁺、Mg²⁺共存体系中对Ni²⁺、Cd²⁺吸附容量分别为139 mg·g^-1和148 mg·g^-1)、选择性能好等优点,回收溶液中镍和镉离子浓度和纯度高(分别为45.15 g·L^-1和 39.17g·L^-1,且C_Ni(Ⅱ)/C_total 0.989,C_Cd(Ⅱ)/C_total 0.994);吸附-洗脱200次后,其物理、化学结构性能稳定;断面形貌变化不明显,交换容量基本不变,可重复使用;比表面积、平均孔径及孔容分别为1189.85 m²·g^-1、30.2 nm 和0.96 cm³·g^-1,热稳定性能好;氮含量从16%降至12%、氧含量由26.49%升至29.96%,交换容量由5.38mmol·g^-1升至6.06 mmol·g^-1。     

氰化尾渣矿浆电解液中铁离子的萃取富集

采用二(2-乙基己基)磷酸酯(P204)-磺化煤油萃取体系从高硫酸氰化尾渣矿浆电解液中富集铁离子,重点研究了P204浓度、相比(O/A)、振荡时间、振荡频率及温度等对Fe³⁺萃取率的影响及其萃取过程。研究表明,在P204体积分数为25%、电解液pH为1.5、温度25℃、O/A=1∶1、振荡时间10 min、振荡频率180r/min的条件下,电解液中Fe³⁺的单级萃取率可达97.73%以上,饱和萃取容量可达到21.57g/L。Fe³⁺在有机相中的萃取富集主要归因于其与P204分子结构中羟基的阳离子交换反应以及磷酰基的配位反应,形成的配合物为FeSO₄A(HA)₃与FeA₃(HA)₃。在草酸1mol/L、O/A=1∶1、振荡时间10min、振荡频率190r/min的条件下,负载有机相中Fe³⁺的单级反萃率可达82.64%以上,反萃液中铁主要以[Fe(C₂O₄)_3<...     

Emulsion liquid membrane for selective extraction of Bi(III)

Di(2-ethylhexyl)phosphoric acid was used as extractant of bismuth ions from nitrate medium by emulsion liquid membrane, with Triton X-100 as the biodegradable surfactant in n-pentanol bulk membrane. The novelties and innovative points of this work are the application of emulsion liquid membrane for selective and efficient extraction of bismuth ions as wel as the relevant optimization procedures. The extraction of bismuth ions was evaluated by the yield of extraction. The experimental parameters were evaluated and optimized, including the ratio of di(2-ethylhexyl)phosphoric acid mass concentration to Triton X-100 (1.0%:0.5%), nature of diluent (n-pentanol), nature and concentration of stripping solution (sulfuric acid, 0.5 mol·L?1), stirring speed (1800 r·min?1) and equilibrium time of extraction (20 min), initial feed solution of bismuth (350 mg·L?1) and the volume ratio of internal stripping phase to membrane phase (14). The experimental parameters of kinetic extraction reveal that the bismuth ions can be extracted by 100%.     

硫代杯[4]冠-4在硝酸体系中对Sr2+的萃取

乏燃料后处理的高放废液分离过程中,发展新型分离材料实现对锶的高效萃取至关重要。合成了1,2交替构象的硫代杯[4]冠-4(TCACE),利用FT-IR、¹H NMR和MS对目标产物进行了表征。研究不同稀释剂对萃取的影响,优化得出CH₂Cl₂为稀释剂,在硝酸浓度为3 mol·L^-1,有机相中硫代杯[4]冠-4浓度为1×10^-3 mol·L^-1,水相中Sr²⁺浓度为5×10^-4 mol·L^-1,萃取温度为25℃,萃取80 min条件下,平均传质系数为1.36×10^{-5 m}·s^-1,Sr²⁺的分配比为0.69。分析了不同条件对硫代杯[4]冠-4对Sr²⁺的萃取影响,研究了萃取计量方程式,实验结果表明萃合物为{Sr(NO₃)₂}·{TCACE}。研究了TCACE对其他金属离子Mo⁶⁺、Ni²⁺、Ag⁺、Sn⁴⁺等的萃取效果,表明对Sr²⁺具有较好的选择性。     

THEORETICAL ANALYSIS OF AMMONIUM REMOVAL IN AN IMMOBILIZED UREASE AND ZEOLITE REACTOR-SEPARATOR

We have developed a theoretical model for predicting the column profiles and effluent histories of a fixed-bed reactor-separator which consists of an immobilized enzyme and an ion exchanger for removing a reaction product. The enzymatic reaction follows the Michaelis-Menten kinetics. The ion exchange process is at local equilibrium and can be described by a linear or a convex isotherm. We have examined the case of urea hydrolysis in a reactor-separator of immobilized urease and zeolite. A step input of urea produces a NH⁺ ₄ concentration wave that increases in amplitude as it propagates through the bed. For a convex isotherm, the peak of the wave propagates through the reactor at an increasing speed. At high reaction rates, a shock (discontinuity of concentration) can develop al t he peak. After the shock formation, the speed of propagation then decreases to almost a constant value. Both the ion exchange parameters and the kinetic parameters affect the shape, the amplitude, and the speed of the wave. A slow speed of propagation and a low leakage of NH⁺ ₄ in the effluent are favored by high ion exchange capacity and selectivity for NH⁺ ₄ high reaction rate, slow flow rate, and reaction kinetics approaching first-order. For a system with a linear ion exchange isotherm, the peak of the NH⁺ ₄ concentration wave propagates through the bed at the same speed as that for an ion exchange bed without reaction. The speed is only affected by the ion exchange parameters. The reaction kinetic parameters only affect the amplitude and the shape of the concentration wave. For systems with a linear ion exchange isotherm, shock does not occur under any reaction conditions.     

CO2 mineralization of carbide slag for the production of light calcium carbonates

The production of polyvinyl chloride by calcium carbide method is a typical chemical process with high coal consumption, leading to massive flue gas and carbide slag emissions. Currently, the carbide slag with high CaO content is usually stacked in residue field, easily draining away with the rain and corroding the soil. In this work, we coupled the treatment of flue gas and carbide slag to propose a facile CO₂ mineralization route to prepare light calcium carbonate. And the route feasibility was comprehensively evaluated via experiments and simulation. Through experimental investigation, the Ca²⁺ leaching and mineralization reaction parameters were determined. Based on the experiment, a process was built and optimized through Aspen Plus, and the energy was integrated to obtain the overall process energy and material consumption. Finally, the net CO₂ emission reduction rate of the entire process through the life-cycle assessment method was analyzed. Moreover, the relationship between the parameters and the CO₂ emission life-cycle assessment was established. The final optimization results showed that the mineralization process required 1154.69 kW·h·(t CO₂)^-1 of energy (including heat energy of 979.32 kW·h·(t CO₂)^-1 and electrical energy of 175.37 kW·h·(t CO₂)^-1), and the net CO₂ emission reduction rate was 35.8%. The light CaCO₃ product can be sold as a high value-added product. According to preliminary economic analysis, the profit of mineralizing can reach more than 2,100 CNY·(t CO₂)^-1.     

Thermodynamical and catalytic aspects of zinc separation from aqueous solution

The present research work examines extraction mechanism of zinc by D2EHPA (Di-2-ethyl hexyl phosphoric acid) and comprehensively studies the main effective parameters on the process. Results of thermodynamic experiments showed that zinc extraction by D2EHPA was endothermic and spontaneous, and thermodynamic parameters including entropy and enthalpy were+27.37 J·mol^-1·K^-1 and 25.21 kJ·mol^-1, respectively. Gibbs free energy was varied between -7.21 kJ·mol^-1 and -8.41 kJ·mol^-1 with the variation of temperature from 20℃ to 70℃. Solution ionic strength was increased by addition of potassium and lithium sulfate solution while addition of calcium sulfate decreased ionic strength whereby zinc extraction efficiency was also decreased. TBP showed positive synergism at concentration of 5% (v/v) and negative synergism effect at concentrations of 2% and 10%. Simultaneous addition of both TBP and salt caused extraction efficiency to drop significantly and lower both TBP and ionic strength efficiency. Results showed that a continuous addition of TBP tends to effectively improve the zinc extraction efficiency. Experiments in the presence of catalyst Ni-Raney demonstrated that zinc extraction kinetic increases remarkably and due to easy recycling of the catalyst, we can propose a novel idea in solvent extraction field.     

Simulation and analysis of multi-stage centrifugal fractional extraction process of 4-nitrobenzene glycine enantiomers☆

Based on the interfacial ligand exchange model and the law of conservation of mass, the multi-stage enantioselective liquid–liquid extraction model has been established to analyze and discuss on multi-stage centrifugal fractional extraction process of 4-nitrobenzene glycine (PGL) enantiomers. The influence of phase ratio, extractant concentra-tion, and PF6?concentration on the concentrations of enantiomers in the extract and raffinate was investigated by experiment and simulation. A good agreement between model and experiment was obtained. On this basis, the influence of many parameters such as location of stage, concentration levels, extractant excess, and number of stages on the symmetric separation performance was simulated. The optimal location of feed stage is the middle of fractional extraction equipment. The feed flow must satisfy a restricted relationship on flow ratios and the liquid throughout of centrifugal device. For desired purity specification, the required flow ratios decrease with extractant concentration and increase with PF6?concentration. When the number of stages is 18 stages at extractant excess of 1.0 or 14 stages at extractant excess of 2.0, the eeeq (equal enantiomeric excess) can reach to 99%.