Na+，K+//Br-，SO42--H2O四元体系323 K相平衡研究

采用等温溶解平衡法研究了四元体系Na⁺,K⁺//Br^-,SO₄^2--H₂O在323 K的相平衡关系,测定了该体系323 K的溶解度及平衡液相的密度,绘制了该体系的相图。研究发现：平衡体系存在复盐钾芒硝Na₂SO₄·3K₂SO₄的结晶区。其相图由3个共饱和点,7条单变量曲线和5个结晶区组成。相区分别对应NaBr·2H₂O、Na₂SO₄、K₂SO₄、KBr和Na₂SO₄·3K₂SO₄结晶区。其中复盐钾芒硝Na₂SO₄·3K₂SO₄,Na₂SO₄和K₂SO₄有较大结晶区,而NaBr·2H₂O和KBr有较小结晶区。对比了等温条件下四元体系Na⁺,K⁺//Cl^-,SO₄^2--H₂O相平衡结果。实验结果表明溴化物对硫酸盐有较强盐析作用。     

氧化程度对微细鳞片可膨胀石墨结构及膨胀性的影响

以平均粒径为19.71μm的天然微细鳞片石墨为原料,通过化学氧化法制备了具有不同氧化程度的可膨胀石墨,采用XRD、FTIR、Raman、SEM等对可膨胀石墨的结构与膨胀性进行了表征。结果表明：当氧化程度较低时制得的微细鳞片可膨胀石墨由石墨、石墨层间化合物和氧化石墨三相组成;随着氧化程度的增加,氧化石墨相含量与可膨胀石墨结构无序程度逐渐增高,石墨层间化合物相含量先增加后减少,石墨相含量则逐渐降低;氧化促使HSO₄^-或SO₄^2-插入石墨层间,插入层间的HSO₄^-或SO₄^2-量是决定可膨胀石墨膨胀容积的关键因素,制备的微细鳞片膨胀石墨的膨胀容积可达65.9mL·g^-1。     

纳米固体超强酸SO42-/Fe2O3的制备及其催化合成乙酸乙酯

将Fe₂O₃纳米粉体经一定浓度的H₂SO₄浸泡活化后制成纳米固体超强酸SO₄^2-/Fe₂O₃,将其用于催化合成乙酸乙酯以考察其活性。利用均匀设计分析了超强酸制备过程及酯化反应过程中各因素的影响,研究结果表明较好的制备条件是:H₂SO₄浓度:2.5mol·L^-1;浸泡时间:1h;活化温度:167℃;活化时间:1h,此时获得的固体超强酸SO₄^2-/Fe₂O₃的粒径小于50nm。当催化剂用量为冰乙酸质量的5%,n(乙醇)∶n(冰乙酸)为3∶1,反应3.5h后乙酸的转化率高于80%。该催化剂经H₂SO₄溶液浸泡、活化再生后可重新使用,推断出其酸强度H₀<-14.5。     

纳米固体超酸SO42-/TiO2的研究

The new nanosolid superacid catalyst SO₄^2-/TiO₂ is compounded with nanometer chemical technology. This catalyst SO₄^2-/TiO₂ has good catalytic effects on esterificational reactions of ethylic acid and ethyl alcohol. It has many other advantages such as strong water-proof quality, being able to be used repeatedly, being easy to be re-claimed, non-corroding, non-polluting. So it is a green industrial catalyst which is helpful to the environment and possesses wide prospect of applications. The crystallo-process, specific surface area and sulphur content of the SO₄^2-/TiO₂ system have been studied with the method of XRD, XPS and the chemical analysis, the result of which indicates that catalytic activity and acid strength of SO₄^2-/TiO₂ is affected by the H₂SO₄ saturant concentration, baking temperature, precipitating condition, specific surface area and sulphur content. The best preparation conditions of SO₄^2-/TiO₂ are: ageing temperature at 0℃, 0.5mol·L^-1 of H₂SO₄ concentration, baking temperature at 500℃and 3 hours of baking time.     

SO42-/SnO2-Fe2O3固体酸催化下的环酮Baeyer-Villiger氧化反应及缩合反应

采用共沉淀的方法制备了不同Fe 掺杂量的SO₄^2-/SnO₂-Fe₂O₃固体超强酸催化剂. 利用傅里叶变换红外(FTIR)光谱, 粉末X射线衍射(XRD), N₂吸附-脱附实验(BET), 热重(TG)分析和扫描电镜(SEM)等方法对样品进行了表征. 考察了所得催化剂对4-叔丁基环己酮与乙二醇缩合反应的催化性能. 实验结果表明, 与未经过掺杂改性的SO₄^2-/SnO₂固体酸催化剂相比, 改性后催化剂的催化性能得到了改善. 研究了以Fe/Sn 摩尔比为0.5的SO₄^2-/SnO₂-Fe₂O₃固体酸为催化剂, 部分醛酮类化合物与乙二醇及1,2-丙二醇的缩合反应. 考察了反应时间、催化剂用量等因素对反应的影响. 同时, 将所得催化剂应用于环酮Baeyer-Villiger 氧化反应中, 催化剂表现出良好的催化活性, 且催化剂具有一定的循环使用性.     

Cu/SO42-/La2O3-ZrO2-Al2O3催化剂的制备及其对C3H6选择还原NO的催化性能

以Al₂O₃为基质，添加ZrO₂和La₂O₃，制成La₂O₃-ZrO₂-Al₂O₃复合载体，然后采用SO₄^2-进行改性，再负载上Cu²⁺，制备了铜基SO₄^2-改性的复合载体催化剂(Cu/SO₄^2-/La₂O₃-ZrO₂-Al₂O₃)。考察了它在富氧条件下对丙烯选择还原NO的催化性能，并借助XRD、SEM、TG、Py-IR、NH₃-TPD、FTIR和TPR等方法研究了Cu/SO₄^2-/La₂O₃-ZrO₂-Al₂O₃的结构和性能的关系。结果表明，ZrO₂的加入主要有利于提高催化剂的低温活性；La₂O₃的加入则主要有利于提高催化剂的热稳定性和还原性能；SO₄^2-能够与Zr形成螯合双配位结构，大幅度促使催化剂表面酸量增加并且酸性增强；因此，有效地提高了Cu/SO₄^2-/La₂O₃-ZrO₂-Al₂O₃在富氧条件下对丙烯选择还原NO的催化活性和水热稳定性。在无水条件下，Cu/SO₄^2-/La₂O₃-ZrO₂-Al₂O₃能使NO的最大转化率高达84.3%，即使在275 ℃ 10%水蒸气存在的情况下，仍能使NO的转化率高达81.2%。     

铕掺杂对Co3O4活化过一硫酸盐降解亚甲基蓝性能的增强

以Co （NO₃）₂和Eu （NO₃）₃为原料,采用草酸盐-热分解法制得了系列不同Co/Eu比例（n_Co/n_Eu）的多孔双金属复合氧化物催化剂,并对其活化过一硫酸盐（PMS）降解亚甲基蓝（MB）的性能进行对比评价。结果表明,按n_Co/n_Eu=9制得的材料（Co₉Eu₁）具有最为优异的活化PMS降解MB的性能。在温度为25℃、催化剂用量和PMS浓度分别为0.10 g·L^-1和0.6 mmol·L^-1的反应条件下,Co₉Eu₁/PMS体系对MB的降解率可达86.66%,而纯Co₃O₄催化下的MB降解率仅为52.62%。Co₉Eu₁出色的催化性能是由于Eu³⁺的缺电子特性增强了对吸附于催化剂表面PMS的极化而使其更易被主催化成分Co₃O₄活化。体系中阴离子C₂O₄^2-和HCO₃^-的存在对Co₉Eu₁/PMS氧化降解MB的性能具有明显抑制作用。猝灭实验和电子顺磁共振谱（EPR）证实Co₉Eu₁/PMS体系中同时存在SO₄^-·、·OH和·O₂^-三种自由基型活性物种以及¹O₂非自由基型活性物种,其中SO₄^-·对MB的氧化降解起关键作用。Co₉Eu₁具有良好的稳定性,在连续4次循环使用中其催化性能未见明显变化。     

电解质水溶液结构研究进展及前景

叙述盐湖中主要离子Li⁺ 、Na⁺ 、K⁺ 、Mg²⁺ 、Ca²⁺ 、Cl^- 、SO^2-₄ 、NO^-₃ 的水溶液和纯水的结构, 简单介绍了主要的研究方法, 分析讨论了溶液结构研究的现状和发展前景。     

双酸位SO42-/ZrO2-SiO2固载离子液体催化剂的构筑及性能

采用一步共缩合-水热法合成酸性载体SO₄^2-/ZrO₂-SiO₂,化学法接枝酸性离子液体磺酸功能化咪唑硫酸氢盐（[Ps-im]HSO₄）,构筑拥有Brönsted与Lewis双酸位的离子液体固载型催化剂SO₄^2-/ZrO₂-SiO₂-IL。采用X射线衍射、傅里叶红外、N₂吸附-脱附、X射线光电子能谱、热重以及透射电镜对催化剂的结构进行表征,结果表明：锆原子和酸性结构SO₄^2-被成功引入纯硅材料,所合成的载体具有一定酸性;离子液体成功固载于酸性介孔材料SO₄^2-/ZrO₂-SiO₂,且固载后的催化剂保持其介孔结构。以大豆油和甲醇的酯交换反应为探针,考察了SO₄^2-/ZrO₂-SiO₂-IL催化剂的催化性能。在反应温度为150℃、反应时间为4 h、催化剂量5%（w/w）、醇油物质的量之比为24：1的反应条件下,生物柴油的收率超过92%,且回收利用5次后,生物柴油的收率仍达86%。     

S掺杂形式对TiO2基光催化剂结构和性能的影响

采用改进的Sol-gel法制备了S-TiO₂和TiO₂,用1 mol·L^-1的H₂SO₄对TiO₂进行表面修饰制成的SO₄^2-/TiO₂。采用XRD、IR、UV-Vis、SEM和EDS等技术对催化剂的结构进行了表征,以L酸(1-萘酚-5-磺酸)为目标物,考察了所制备的催化剂的性能．结果表明：S-TiO₂的禁带宽度明显降低,并且对400~650 nm区域的可见光都有一定的吸收,其可见光活性和紫外光活性均高于SO₄^2-/TiO₂和纯TiO₂。     

CoFe2O4 with MoS2-xOy Nanosheets as a Co-catalyst for Enhanced Activation of Peroxydisulfate in Advanced Oxidation Processes

The application of advanced oxidation processes (AOPs) based on sulfate radicals for degrading persistent organic pollutants faces challenges due to the inefficient activation of peroxydisulfate (PDS) oxidant. Herein, a composite CoFe₂O₄/MoS_2-xO_y (CFM) catalyst consisting of CoFe₂O₄ nanoparticles uniformly dispersed on the nanosheets of oxygen-incorporated MoS₂ (MoS_2-xO_y) with flower-like morphology are fabricated through a facile two-step hydrothermal method, which results in the enhanced activation of PDS and a highly efficient degradation of phenolic pollutants. The oxygen-doping in MoS_2-xO_y leads to unsaturated sulfur and active sites on the surface of MoS₂ for accelerating the rate limiting step of Fe^III/Fe^II reduction cycle in PDS-CFM reaction. Aiming at the refractory organic pollutants in actual coking wastewater, CFM co-catalyst is introduced into a hydrogel made up of polyvinyl alcohol (PVA) and coal-tar pitch oxides (PO) to construct a multifunctional CFM@PO/PVA hydrogel. Upon hybrid CFM@PO/PVA, the coupling of the enhanced AOP with solar-driven interfacial vapor generation (SIVG) technology contributes to the degradation efficiency, the removal rate of phenol in solution and the total organic carbon in coking wastewater can reach 98 % and 91 %, respectively. The integration of heterogeneous AOPs with SIVG system provides a feasible strategy for the eco-friendly efficient purification of industrial wastewater.     

Plasmonic osmium hydrosols: Preparation,characterization, and properties

A simple route for the synthesis of mesoporous and plasmonic chitosan supported osmium hydrosols (Os⁰) has been reported using osmium (III)-sodium borohydride redox reaction at room temperature. The composition and morphology of nanoparticles were determined with XRD, XPS, TEM, EDX, SEM, FTIR and N₂-adsorption desorption techniques. No SPR band of Os⁰ at 485 nm was observed for the same redox reaction with cetyltrimethylammonium bromide (CTAB) for ca. 120 min at room temperature. The surface oxidation of Os⁰ into OsO₂ was detected by XRD and XPS. XRD shows the presence of chitosan onto the surface of nanoparticles. The average pore size, and pore volume were found to be 7.23 nm, and 0.239 cc/g, respectively, for Os⁰. The persulfate activation catalytic activity was tested in situ chemical oxidation of basic red 2 (safranin) under activated and un-activated persulfate. Safranin was adsorbed onto the Os⁰ and complex was formed. The oxidation of dye follows pseudo-first order kinetics (k_app = 14.8 × 10^-3 min⁻¹ at [S₂O₈^2-] = 3.3 mM). The activated system showed a much higher dye oxidation rate compared to either S₂O₈^2- or Os⁰ alone. The activation energy (E_a = 105 kJ/mol) was calculated for the system by using Arrhenius equation. The reaction mechanism of Os⁰ activation of persulfate was elucidated and discussed.     

Structural Modulation on NiCo2S4Nanoarray by N Doping to Enhance 2e-ORR Selectivity for Photothermal AOPs and Zn−O2Batteries**

As a H₂O₂ generator, a 2e⁻ oxygen reduction reaction active electrocatalyst plays an important role in the advanced oxidation process to degrade organic pollutants in sewage. To enhance the tendency of NiCo₂S₄ towards the 2e⁻ reduction reaction, N atoms are doped in its structure and replace S²⁻. The result implies that this weakens the interaction between NiCo₂S₄ and OOH*, suppresses O−O bond breaking and enhances H₂O₂ selectivity. This electrocatalyst also shows photothermal effect. Under photothermal heating, H₂O₂ produced by the oxidation reduction reaction can decompose and releaseOH, which degrades organic pollutants through the advanced oxidation process. Photothermal effect induced by the advance oxidation process shows obvious advantages over the traditional Fenton reaction, such as wide pH adaptation scope and low secondary pollutant due to its Fe²⁺ free character. With Zn as anode and the electrocatalyst as cathode material, a Zn−O₂ battery is assembled. It achieves electricity generation and photothermal effect induced by the advance oxidation process simultaneously.     

Oxidative degradation of phenols in sono-Fenton-like systems upon high-frequency ultrasound irradiation

The kinetics of oxidative degradation of phenol and chlorophenols upon acoustic cavitation in the megahertz range (1.7 MHz) is studied experimentally in model systems, and the involvement of in situ generated reactive oxygen species (ROSs) is demonstrated. The phenols subjected to high frequency ultrasound (HFUS) are ranked in terms of their rate of conversion: 2,4,6-trichlorophenol > 2,4-dichlorophenol ~ 2-chlorophenol > 4-chlorophenol ~ phenol. Oxidative degradation upon HFUS irradiation is most efficient at low concentrations of pollutants, due to the low steady-state concentrations of the in situ generated ROSs. A dramatic increase is observed in the efficiency of oxidation in several sonochemical oxidative systems (HFUS in combination with other chemical oxidative factors). The system with added Fe²⁺ (a sono-Fenton system) derives its efficiency from hydrogen peroxide generated in situ as a result of the recombination of OH radicals. The S₂O₈^2-/Fe²⁺/HFUS system has a synergetic effect on substrate oxidation that is attributed to a radical chain mechanism. In terms of the oxidation rates, degrees of conversion, and specific energy efficiencies of 4-chlorophenol oxidation based on the amount of oxidized substance per unit of expended energy the considered sonochemical oxidative systems form the series HFUS < S₂O₈^2-/HFUS < S₂O₈^2-/Fe²⁺/HFUS.     

The capacity and mechanisms of various oxidants on regulating the redox function of ZVI

It is well known that zero-valent iron(ZVI) could catalyze the oxidation of various oxidants to realize the rapid oxidation removal of pollutants. However, in this study, we found that the addition of different oxidants could regulate the redox function of ZVI system. In three different co-treatment systems, the effects of different oxidizers(peroxymonosulfate(PMS), persulfate(PDS), hydrogen peroxide(H_2O_2))dosages on the ratios of oxidative degradation rate and reductive degradation rate of p-nitrophenol(PNP)were studied. The effect of the H~+ released from oxidizers and the generated reactive oxygen species(ROS) in ZVI/PMS, ZVI/PDS, ZVI/H_2O_2 systems were detailed discussed. Especially, the contribution of generated ROS for reductive degradation of PNP was quantified in the ZVI/H_2O_2 system. Based on the results of TOC removal, UV–vis absorption spectra, and intermediates concentration curves, it was found that the degradation of PNP changed from reduction to oxidation with the increase of oxidant proportion.When the molar ratio of ZVI to oxidizer equal to 100, PNP was mainly degraded by reduction accompanied by slight oxidation. Combined with the results of SEM-EDS and XPS, it was confirmed that the enhanced degradation of PNP under the addition of oxidant was mainly related to the generated ROS,the additional H~+, and the corrosion products of ZVI.     

Reaction of poly(vinyl alcohol) with potassium persulfate and graft copolymerization

A study of the oxidation of poly(vinyl alcohol) (PVAL) by potassium persulfate (KPS) in aqueous solutions showed that the decomposition of KPS was greatly enhanced by the presence of PVAL, its hydroxyl groups being oxidized to ketones in a yield of about one mole of ketone from one mole of KPS. The decomposition rate of KPS was found to be given by the equation, ?d[S₂O₈^2?]/dt = k[S₂O₈^2?] [PVAL]^1/2, which was essentially the same as in the oxidation of alcohols of low molecular weight by persulfate ion. The occurrence of gelation of PVAL solutions and graft copolymerization of methyl methacrylate (MMA) onto PVAL in the presence of KPS was evidence for PVAL radical as an intermediate species in the oxidation of PVAL. A characterization study was also carried out for the reaction products of the graft copolymerization of MMA onto PVAL with KPS in dimethyl sulfoxide solution.     

Mechanisms of interactions involving formation and rupture of S-S bonds in inorganic sulphur OXO-derivative systems

Mechanisms of ten redox interactions involving inorganic sulphur oxo-derivative systems thiosulphate (S_bS_aO₃ ^2-) and polythionate (O₃ ^-S_a(S_b)_nS_aO₃ ^-) have been investigated where S_a is a sulphur centre directly coordinated by oxygens and one sulphur-b (S_b); S_b is a sulphur atom either directly bonded to S_a or any one of the others catenated to one adjacent to S_a. The degree of lability of the S-S bonds of these systems towards the hydroxyl anion is a function of its concentration and also of other species in the medium. In a weak concentration of hydroxyl anion medium, iodine effects only breakage of the π(S_a-S_b) bond of S_bS_aO₃ ^2-. One electron from this bond migrates to S_a and another to S_b to give S^* _bS^* _aO₃ ^2-. An electron from one anionic oxygen reduces the oxidant. Then one electron from this oxygen pairs with the S_a unpaired electron to form a new π(S_a-O) bond and highly reactive S^* _bS_aO₃ ^- radicals, two of which couple to form the S_b-S_b bond of the tetrathionate anion (O₃ ^-S_a(S_b)₂S_aO₃ ^-). However, above a minimum OH^- concentration for some interactions, the S_a=S_b bond completely breaks to yield S_aO₃ ^2- and S_b such that in the presence of iodine, nascent oxygen (O) and H^- from OH^- oxidizes S_aO₃ ^2-/S_b to S_aO₄ ^2-/S_bO₄ ^2- and reduces iodine respectively. In the absence of an oxidant, OH^- reduces two-thirds of S_b to S^b _2- with a concomitant yield of *OH which oxidizes a third of S_b to S_bO³ _2- leaving S_aO₃ ^2- intact.     

Oxidative transformation of organic compounds using bis(1,10-phenanthroline)silver(II) peroxydisulfate as a twin catalyst/oxidant

The mild and efficient oxidation of a variety of organic functional groups with a twin catalyst/oxidant, bis(phenanthroline)silver(II) peroxydisulfate, [Ag(phen)₂]S₂O₈, is reported. This reagent shows high selectivity and the type of obtained products and the extent of oxidation are strongly dependent to the type of the functional groups and oxidant/substrate molar ratios.     

Crown Ether As The Phase-Transfer Catalyst for Free Radical Polymerization of Hydrophobic Vinyl Monomers

Various crown ethers were used as phase-transfer catalysts for free radical polymerizations of some water-insoluble vinyl monomers such as acrylonitrile, methylmethacrylate and styrene with persulfate as initiator. The catalytic abilities of these crown ethers for free radical polymerization of acrylonitrile with S₂O₈^2?ion as an initiator were in the order: 18-crown-6 > 15-crown-4 > 12-crown-4 > benzo-15-crown-5 > dibenzo-18-crown-6. Among various persulfates such as Na₂S₂O₈ K₂S₂O₈ and (NH₄)₂S₂O₈, ammonium persulfate was the optimum initiator for the polymerization of acrylonitrile catalyzed by 18-crown-6 or 15-crown-5. Among the organic solvents used, chloroform seems to be the best solvent for the catalytic polymerization of acrylonitrile. An apparent activation energy of 72.9 kJ mol^?1 was observed for the polymerization of acrylonitrile. The catalytic reaction rates of free radical polymerization for these hydrophobic vinyl monomers were in the order: acrylonitrile > methylmethacrylate > styrene > isoprene. Effects of concentrations of crown ether, initiator, and nitrogen on the polymerization of these vinyl monomers were investigated.     

Combustion synthesis of mesoporous CoAl2O4 for peroxymonosulfate activation to degrade organic pollutants

A mesoporous cobalt aluminate (CoAl₂O₄) spinel is synthesized through a combustion method and adopted for the activation of peroxymonosulfate (PMS) to degrade organic pollutants. Multiple characterization procedures are conducted to investigate the morphology and physicochemical properties of the CoAl₂O₄ spinel. Due to its mesoporous structure, large surface area, and high electrical conductivity, the obtained CoAl₂O₄ exhibits remarkable catalytic activity for Rhodamine B (RhB) degradation. Its RhB degradation rate is 89.0 and 10.5 times greater than those of Co₃O₄ and CoAl₂O₄ spinel prepared by a precipitation method, respectively. Moreover, the mesoporous CoAl₂O₄ spinel demonstrates a broad operating pH range and excellent recyclability. The influence of several parameters (catalyst amount, PMS concentration, initial pH, and coexisting inorganic anions) on the oxidation of RhB is evaluated. Through quenching tests and electron paramagnetic resonance experiments, sulfate radicals are identified as the predominant reactive species in RhB degradation. This paper provides new insights for the development of efficient, stable, and reusable cobalt-based heterogeneous catalysts and promotes the application of persulfate activation technology for the treatment of refractory organic wastewater.