共查询到20条相似文献,搜索用时 515 毫秒
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为了提高磷酸二氢钾的纯度、白度以及透明度,在以钙水为原料生产磷酸二氢钾过程中,采用活性炭脱色,调节母液pH脱除Ca2+,加入BaCl2饱和溶液脱除SO24-。结果表明,磷酸二氢钾粗母液中加3.5g/100mL活性炭脱色,经过滤后用KOH饱和溶液调节pH至6.0左右,然后按n(BaCl2)/n(SO24-)=1.0加入BaCl2饱和溶液脱除SO24-,在净化过程中磷和钾有少量损失,Ca2+、SO24-脱除效果较好,并且对其它金属阳离子也有一定的脱除效果。净化母液经蒸发、结晶后得到的磷酸二氢钾产品达到国家工业级一等品标准。 相似文献
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综述了目前膜法脱除天然气中二氧化碳的工艺技术发展现状。首先对比了天然气脱除二氧化碳多种工艺技术特点及应用场合情况,膜分离法相比于其他分离方法,具有投资较少、占地小、耗能少等优势。介绍了膜法分离原理、膜材料、膜组件发展现状和膜法脱除天然气中二氧化碳工艺技术单元情况。而工艺技术单元又分为预处理单元和膜分离单元:预处理单元根据采出原料气成分选择不同脱除方法进行组合;原料气经预处理单元后进入膜分离单元,根据实际工况,综合考虑烃类回收率、占地、能耗、投资等因素合理地设计膜法脱碳分离工艺。然后又对国内外膜法脱除天然气中二氧化碳应用案例进行介绍,目前国外膜法脱除天然气中二氧化碳应用案例较多,而国内应用案例较少,因此需加大国内膜法脱除天然气中二氧化碳的工业应用。最后对天然气膜法脱除二氧化碳技术发展方向进行了展望,指出研发具有自主知识产权并且在实际复杂工况条件下能保持高性能、长周期稳定性的膜材料是未来膜分离技术发展的重点,同时将两种或两种以上的单一脱除二氧化碳技术相结合的耦合集成组合工艺,如膜法分离+化学吸收法、膜法分离+变温吸附法等,这种耦合集成组合工艺为未来脱碳工艺技术发展提供了新方向。 相似文献
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《现代化工》2020,(10)
为解决硫酸盐废水微生物降解过程中厌氧微生物生长缓慢、生物质易流失的问题,研究了一种大孔聚苯乙烯/有机硅树脂[Poly(St/MTQ) HIPE,简称PSMH]球型载体的制备方法,并将其作为填料应用于升流式固定床生物膜反应器,固定硫酸盐还原菌后进行废水处理。对反应器在不同进水SO24-质量浓度、COD/SO24-质量浓度比条件下的脱硫效能进行评价,并通过扫描电镜考察微生物在PSMH载体上的生长情况。结果表明,反应器在进水SO24-质量浓度为3 681. 6 mg/L、COD/SO24-质量浓度比为2. 40时,平均SO24-脱除速率达1. 87 kg/(d·m3),平均SO24-脱除率达94. 6%。PSMH适宜的孔道结构有利于硫酸盐还原菌在其表面及内部粘附生长。 相似文献
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分析了多组分无机盐溶液混合体系的性质,以加热、添加CaCl2溶液等各种方法处理液体,研究其SO42-含量的变化,以达到脱除SO24-的目的。以石灰石及浓盐酸为原料反应生成的CaCl2溶液作添加剂,考察和比较了CaCl2溶液的用量、体系的反应温度、反应时间等因素对SO24-去除效果的影响。并在此基础上考虑其处理成本,得出最佳工艺生产条件:添加剂中的钙离子和原液中SO42-的质量比为0.389∶1,反应温度为30℃,反应时间为4 h,可获得SO42-的质量浓度低于5 g/L的满意效果,达到了企业对盐溶液中SO42-含量的要求。此方法具有一定的应用价值和商业价值。 相似文献
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This paper distinguishes between two different scales of medium range order, MRO, in non-crystalline SiO2: (1) the first is ~0.4 to 0.5 nm and is obtained from the position of the first sharp diffraction peak, FSDP, in the X-ray diffraction structure factor, S(Q), and (2) the second is ~1 nm and is calculated from the FSDP full-width-at-half-maximum FWHM. Many-electron calculations yield Si–O third- and O–O fourth-nearest-neighbor bonding distances in the same 0.4–0.5 nm MRO regime. These derive from the availability of empty Si dπ orbitals for back-donation from occupied O pπ orbitals yielding narrow symmetry determined distributions of third neighbor Si–O, and fourth neighbor O–O distances. These are segments of six member rings contributing to connected six-member rings with ~1 nm length scale within the MRO regime. The unique properties of non-crystalline SiO2 are explained by the encapsulation of six-member ring clusters by five- and seven-member rings on average in a compliant hard-soft nano-scaled inhomogeneous network. This network structure minimizes macroscopic strain, reducing intrinsic bonding defects as well as defect precursors. This inhomogeneous CRN is enabling for applications including thermally grown ~1.5 nm SiO2 layers for Si field effect transistor devices to optical components with centimeter dimensions. There are qualitatively similar length scales in nano-crystalline HfO2 and phase separated Hf silicates based on the primitive unit cell, rather than a ring structure. Hf oxide dielectrics have recently been used as replacement dielectrics for a new generation of Si and Si/Ge devices heralding a transition into nano-scale circuits and systems on a Si chip. 相似文献
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介绍了盐水除硫酸根的工艺及技术特点,对钡法与膜法除硝工艺及其在经济效益方面进行了对比,得出了膜法优于钡法除硝技术的结论。 相似文献
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提出了一种简便、低成本的聚偏氟乙烯(PVDF)微孔膜表面疏水增强方法——溶胀辊轧法,以微结构辊筒对表面喷涂溶胀剂的PVDF成品微孔膜辊轧后,采用浸没凝胶法成膜。以N-甲基吡咯烷酮/水(非溶剂)为溶胀体系,采用扫描电子显微镜(SEM)、原子力显微镜(AFM)、水接触角(WCA)、最大孔径、平均孔径、N2通量、耐磨性、液体穿透压(LEP)等表征手段,系统地研究了溶胀剂体系、溶胀剂容量对PVDF微孔膜结构与性能的影响。结果表明:辊轧膜表面呈现微米-亚微米层次特征,溶胀辊轧操作起到了疏水增强、透过能力提升的效果。溶胀剂中水(非溶剂)质量分数为6%、喷涂密度为0.03mL/cm2时,膜性能最优。连续运行30h的真空膜蒸馏(VMD)对比实验表明,辊轧膜较未辊轧膜具有更高的产水通量、脱盐率及更好的耐污染性能。该方法为低成本、连续化进行成品膜表面疏水强化提供了一种新选择。 相似文献
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《Ceramics International》2023,49(7):10682-10691
This work investigates the feasibility of laser engraving of silicon carbide by adopting a Q-Switched fiber laser. To study the effect of the laser parameters on the laser-material interaction, a 33 full factorial plan was developed and tested. During the tests, the following laser parameters were varied: scanning speed, pulse frequency, which affects the pulse power, and the number of repetitions, i.e., the number of times the laser beam passes on the same line. After the tests, digital microscopy was used to measure the depth of the engraved pocket, and a 3D laser profilometer was used to acquire the pocket surface and morphology and to calculate the main roughness parameters. The analysis of variance (ANOVA) was carried out in order to detect how the process parameters affect laser machining. The Response Surface Methodology (RSM) was additionally performed to obtain the regression model and finally, the Multi-Response Optimization (MRO) was implemented to identify the optimal process conditions. The results show that it is possible to machine pockets with low roughness (Ra <1 μm) at high material removal rates (MRR> 0.1 mg/s). 相似文献
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Control of acid-site location of ZSM-5 zeolite membrane and its application to the MTO reaction 总被引:1,自引:0,他引:1
Teruoki Tago Kazuyuki Iwakai Ken Morita Katsunori Tanaka Takao Masuda 《Catalysis Today》2005,105(3-4):662-2
ZSM-5 zeolite membrane, which shows high selectivity toward olefins in the methanol conversion, was developed by controlling the location of the acid sites. First, the ZSM-5 zeolite catalyst membrane without pinholes was successfully prepared by synthesizing a ZSM-5 zeolite layer on an outer surface of a cylindrical alumina ceramic filter. The membrane was used as the catalytic membrane reactor to recover olefins from methanol. Though the olefins were successfully produced from methanol with high selectivity (ca. 80%), production of paraffin and aromatics was observed at the feed side of the zeolite membrane. To prevent the such production, the location of the acid site of the ZSM-5 zeolite membrane was controlled by a new method called the catalytic cracking of silane (CCS) method. Selective deactivation of acid sites at the outer surface of the zeolite membrane (feed side of reactant) by the CCS method allowed us to increase the selectivity of the olefins by 10% as compared to the untreated membrane. 相似文献
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以邻苯二甲酸二丁酯(DBP)和N,N-二甲基乙酰胺(DMAc)为混合稀释剂,采用热致相分离法(TIPS)制备了聚偏氟乙烯(PVDF)/酚酞型聚醚砜(PES-C)共混膜,考察了不同凝固浴温度对膜结构和性能的影响。采用扫描电镜观察了膜的结构,测试了膜的纯水通量。运用DSC和XRD方法检测了膜的结晶性能。将制备的膜在膜生物反应器(MBR)中运行测试了膜的污水通量和出水指标。随凝固浴温度的升高,共混膜的最高熔融温度上升,膜中α晶型的含量增加。在凝固浴温度为25℃时,膜形成了较为致密的皮层结构和较为疏松的支撑层结构,此时共混膜的纯水通量和污水通量达到最大值,且MBR出水COD和NH4+-N含量达到排放要求。 相似文献