二氧化硫还原法处理含铬废水最佳工艺条件研究

试验采用自主研发设计的二氧化硫还原连续反应处理高浓度含铬废水的工艺,研究了二氧化硫还原反应时不同pH值、反应时间、反应温度和硫磺投料量对含铬废水中六价铬污染物的治理效果。结果表明：当二氧化硫还原反应条件控制在pH值为2-4、反应温度为40-60℃、硫磺投料量为理论反应所需投料量的1.2倍、反应时间为40min时,可使高浓度含铬废水中的六价铬得到有效去除。

二氧化硫还原分金后液工艺研究

针对大冶有色公司铜阳极泥处理流程中的中间产物分金后液采用亚硫酸钠还原+锌粉置换工艺回收存在选择性差、后续分离流程复杂等问题,探索了粗碲粉工艺和粗二氧化碲工艺2种新的工艺路线。结果表明:2种新工艺处理后尾液均达到亚硫酸钠还原+锌粉置换工艺指标;亚硫酸钠还原+锌粉置换工艺材料成本545元/m^(3),粗碲粉工艺材料成本554元/m^(3),粗二氧化碲工艺材料成本459元/m^(3),选择粗二氧化碲工艺较优,可节约成本约为64.5万元/a。

二氧化硫还原法处理高浓度含铬废水

将铬盐生产中产生的含铬废水调查，铬含量在≤800 mg/l的含铬废水加酸调节PH值在2～3，与硫磺燃烧产生的8-9%SO2的混合炉气反应，将六价铬还原为三价铬，再与NaOH溶液中和生成Cr(OH)3沉淀。过滤处理后废水：Cr6+≤0.5mg/l， Cr总≤1.5 mg/l， PH=7～9，可达标回用；滤饼作铬绿原料；吸收尾气用碱处理达标排放；实现清洁生产，实现资源的循环利用。

综合法二氧化氯生产系统废水除铬实例

以某浆纸厂含铬废水处理工程实例为研究对象,针对综合利用自产化学药品和现有设备开发的间歇性六价铬(Cr^(6+))综合处理系统,探讨了二氧化氯车间Cr^(6+)废水产生原因及性质,根据不同的反应池pH值、反应温度、反应时间和硫磺投加量对废水中Cr^(6+)还原效果的影响,确定了二氧化硫还原法去除Cr^(6+)的最佳反应条件,并结合实际生产数据,展示了Cr^(6+)还原效果。结果表明,有效去除高浓度含铬废水中Cr^(6+)的条件为:pH值=2~4、反应温度控制在40~60℃、硫磺投加量为理论反应所需投加量的1.4~1.6倍、反应时间40 min。3次二氧化氯车间停修废水出水中Cr^(6+)含量均低于0.005 mg/L,总铬含量均低于0.06 mg/L,符合《污水综合排放标准》(GB 8978—1996)中的要求,证实了间歇性Cr^(6+)综合处理系统处理的有效性。

二氧化硫还原法处理含铬废水最佳工艺条件研究

试验采用自主研发设计韵二氧化硫还原连续反应处理高浓度含铬废水的工艺，研究了二氧化硫还原反应时不同pH值、反应时闽、反应温度和硫磺投料量对含铬废水中穴价铬污染物的治理效果。结果表明：

二氧化碲制备碲粉新工艺生产实践

二氧化碲盐酸浸出-二氧化硫还原是生产碲的新工艺,该工艺流程短、设备配置简单、回收率高,具有较好的应用前景。本文考察该工艺中浸出温度、浸出时间、浸出液固比、预还原时间、还原时间、还原温度等参数对碲回收率的影响,并创新性地提出铁粉深度还原降低后液含碲措施,以提升碲还原率及回收率。主要得到以下结论:在浸出温度65℃、浸出时间60 min、浸出液固比3:1、预还原时间5 min、还原时间6 h、还原温度70℃的条件下,碲的浸出率为95.5%,还原率为91.5%,碲粉经洗涤浇铸后可获得满足Te9995牌号标准的精碲。通过铁粉深度还原含碲后液,可将碲的还原率进一步提升至96%,流程碲回收率达91.68%。相比于电积工艺,新工艺可缩短生产周期95%,实现了碲产品高效产出与经济效益提升。

Chalcogen heteroatoms doped nickel-nitrogen-carbon single-atom catalysts with asymmetric coordination for efficient electrochemical CO_(2) reduction

The electronic configuration of central metal atoms in single-atom catalysts(SACs)is pivotal in electrochemical CO_(2) reduction reaction(eCO_(2)RR).Herein,chalcogen heteroatoms(e.g.,S,Se,and Te)were incorporated into the symmetric nickel-nitrogen-carbon(Ni-N_(4)-C)configuration to obtain Ni-X-N_(3)-C(X:S,Se,and Te)SACs with asymmetric coordination presented for central Ni atoms.Among these obtained Ni-X-N_(3)-C(X:S,Se,and Te)SACs,Ni-Se-N_(3)-C exhibited superior eCO_(2)RR activity,with CO selectivity reaching~98% at-0.70 V versus reversible hydrogen electrode(RHE).The Zn-CO_(2) battery integrated with Ni-Se-N_(3)-C as cathode and Zn foil as anode achieved a peak power density of 1.82 mW cm^(-2) and maintained remarkable rechargeable stability over 20 h.In-situ spectral investigations and theoretical calculations demonstrated that the chalcogen heteroatoms doped into the Ni-N_(4)-C configuration would break coordination symmetry and trigger charge redistribution,and then regulate the intermediate behaviors and thermodynamic reaction pathways for eCO_(2)RR.Especially,for Ni-Se-N_(3)-C,the introduced Se atoms could significantly raise the d-band center of central Ni atoms and thus remarkably lower the energy barrier for the rate-determining step of ^(*)COOH formation,contributing to the promising eCO_(2)RR performance for high selectivity CO production by competing with hydrogen evolution reaction.

再论铬鞣剂及应用技术

迄今为止,铬鞣剂是皮革制造重要材料,其鞣革性能是其他鞣剂无法达到的,再次理解现代铬鞣剂的功能是非常有益的。利用现代鞣制方法对糖还原的液体铬浆(GCr-L)、糖还原铬粉(GCr-S)及二氧化硫还原铬粉(SCr-S)三种鞣剂应用特征进行探索,包括:三种鞣剂的水解与光谱吸收特征;用铬鞣剂在浸酸牛皮中渗透吸收情况及鞣革性能进行对比研究;不同铬鞣剂对鞣后复鞣染整的影响。结果表明:GCr-L与GCr-S水解初期pH较低,接近平衡的pH差距较小,吸收光谱紫移。因此,组成较复杂,有机配合物含量多,导致鞣制渗透速率和吸收率都相对SCr-S较差。在相同Cr_2O_3用量下铬鞣坯革比较,SCr-S鞣革的物理力学性能优于其它两种鞣革。但三种铬鞣剂鞣革经过染色、加脂后无明显差别,成革质量相同。

Reduction and deposition of arsenic in copper electrolyte

The influences of temperature, H2SO4 concentration, CuSO4 concentration, reaction time and SO2 flow rate on the reduction of arsenic（V） with SO2 were studied and the deposition behavior of arsenic （III） under the effect of concentration and co-crystallization was investigated in copper electrolyte. The results indicate that reduction rate of arsenic （V） decreases with increasing temperature and H2SO4 concentration, but increases with increasing SO2 flow rate and reaction time, and it can reach 92% under appropriate conditions that reaction temperature is 65 °C, H2SO4 concentration is 203 g/L, CuSO4 concentration is 80 g/L, reaction time is 2 h and SO2 gas flow rate is 200 mL/min. To remove arsenic in the copper electrolyte, arsenic （V） is reduced to trivalence under the appropriate conditions, the copper electrolyte is concentrated till H2SO4 concentration reaches 645 g/L, and then the removal rates of As, Cu, Sb and Bi reach 83.9%, 87.1%, 21.0% and 84.7%. The XRD analysis shows that crystallized product obtained contains As2O3 and CuSO4·5H2O.

Catalytic reduction of SO_2 by CO over CeO_2-TiO_2 mixed oxides

The structure and catalytic desulfurization characteristics of CeO2-TiO2 mixed oxides were investigated by means ofX-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and catalytic activity tests. According to the results, a CeO2-TiO2solid solution is formed when the mole ratio of cerium to titanium n（Ce）：n（Ti） is 5：5 or greater, and the most suitable n（Ce）：n（Ti） isdetermined as 7：3, over which the conversion rate of SO2 and the yield of sulfur at 500℃ reach 93% and 99%, respectively.According to the activity testing curve, Ce0.7Ti0.3O2 （n（Ce）：n（Ti）=7：3） without any pretreatment can be gradually activated by reagentgas after about 10 min, and reaches a steady activation status 60 min later. The XPS results of Ce0.7Ti0.3O2 after different time ofSO2＋CO reaction show that CeO2 is the active component that offers the redox couple Ce4＋/Ce3＋ and the labile oxygen vacancies, andTiO2 only functions as a catalyst structure stabilizer during the catalytic reaction process. After 48 h of catalytic reaction at 500℃,Ce0.7Ti0.3O2 still maintains a stable structure without being vulcanized, demonstrating its good anti-sulfur poisoning performance.

从湿法冶炼废水中回收金

介绍了用SO2 还原沉淀 ,用NaOH浸煮除杂质等工序回收湿法冶炼废水及废水沉淀物中金的过程。该工艺不仅能回收金 ,还可回收其它有价金属 (Cu、Pb) ,是一种操作简便。

锰铁合金炉灰资源化利用的试验研究

以锰铁合金炉灰为原料 ,分别用二氧化硫还原法和烧结法制备硫酸锰溶液 ,试验和实际研究结果表明 ,以锰铁合金炉灰为原料制备硫酸锰溶液是经济可行的。

Ozonation of Sulfur Dioxide in Sulphuric Acid Solution

In this study, the oxidation rates of sulfur dioxide （SO2） in sulphuric acid solution by ozone and oxygen were compared, and the oxidation mechanism of ozone on SO2 was investigated. The results showed that the oxidation-reduction potential of the acidic solution was enhanced, the transformation rate of sulfuric acid to sulphuric acid was increased and the absorption driving force was improved in the presence of ozone. By comparing the amount of sulfate ions measured in the experiments and the theoretical amount of sulfate ions calculated from the amount of ozone consumed in the reaction, it can be confirmed that oxygen free radicals from dissociation of ozone are reactive as an efficient oxidant and oxygen from ozone generator participates in the reaction with SO2. 0.602 mol of effective oxygen was introduced into the reaction by one mole of ozone in 10.15 rain at sulphuric acid concentration of 3% （by mass）, SO2 concentration of 1.33% （by volume） and oxygen flow rate of 1.5 L.min^-1 from ozone generator.

Ho-modified Mn-Ce/TiO_2 for low-temperature SCR of NO_x with NH_3:Evaluation and characterization

Low‐temperature selective catalytic reduction(SCR)of NO with NH3 was tested over Ho‐doped Mn–Ce/TiO2 catalysts prepared by the impregnation method.The obtained catalysts with different Ho doping ratios were characterized by Brunauer‐Emmett‐Teller(BET),X‐ray diffraction(XRD),temperature‐programmed reduction(H2‐TPR),temperature‐programmed desorption of NH3(NH3‐TPD),X‐ray photoelectron spectroscopy(XPS),and scanning electron microscopy(SEM).The catalytic activities were tested on a fixed bed.Their results indicated that the proper doping amount of Ho could effectively improve the low‐temperature denitrification performance and the SO2 resistance of Mn–Ce/TiO2 catalyst.The catalyst with Ho/Ti of 0.1 presented excellent catalytic activity,with a conversion of more than 90%in the temperature window of 140–220°C.The characterization results showed that the improved SCR activity of the Mn–Ce/TiO2 catalyst caused by Ho doping was due to the increase of the specific surface area,higher concentration of chemisorbed oxygen,higher surface Mn4+/Mn3+ratio,and higher acidity.The SO2 resistance test showed that the deactivating influence of SO2 on the catalyst was irreversible.The XRD and XPS results showed that the main reason for the catalyst deactivation was sulfates that had formed on the catalyst surface and that Ho doping could inhibit the sulfation to some extent.

我国铬盐现状与展望

铬盐是无机化工的主要系列产品之一，广泛用于化工、轻工、冶金、纺织、印染、机械、仪器、仪表、日用五金、制革、医药、建材、木材加工等行业，在国民经济和人民生活中起着相当重要的作用，据统计，我国国民经济中约15％的产品与铬盐相关。重铬酸钠(商品名称为红矾钠)和铬酸酐是生产其它铬化合物的基础产品，为便于统计和可比，习惯上把其它铬盐延伸产品折算成红矾钠，统称为红矾钠总量。

Structural Basis for the Thermostability of Sulfur Oxygenase Reductases

The thermostability of three sulfur oxygenase reductases （SORs） was investigated from thermoacidophilic achaea Acidianus tengchongensis （SORAT） and Sulfolobus tokodaii （SORsT） as well as the moderately thermophilic bacterium Acidithiobacillus sp. SM-1 （SORsB）. The optimal temperatures for catalyzing sulfur oxidation were 80 ℃ （SORAT）, 85 ℃ （SORsT）, and 70 ℃ （SORsB）, respectively. The half-lives of the three SORs at their optimal catalytic conditions were 100 min （SORAT）, 58 min （SORsT）, and 37 min （SORsB）. In order to reveal the structural basis of the thermostability of these SORs, three-dimensional structural models of them were generated by homology modeling using the previously reported high-resolution X-ray structure of SORAA （from Acidianus ambivalens） as a template. The results suggest that thermostability was dependent on： （a） high number of the charged amino acid glutamic acid and the flexible amino acid proline, （b） low number of the therraolabile amino acid glutamine, （c） increased number of ion pairs, （d） decreased ratio of hydrophobie accessible solvent surface area （ASA） to charged ASA, and （e） increased volumes of the cavity. The number of cavities and the number of hydrogen bonds did not signifieantly affect the thermostability of SORs, whereas the cavity volumes increased as the thermal stability increased.

Grafted Deproteinized Natural Rubber as an Impact Modifier in Styrene-Methyl Methacrylate Copolymer Sheet

This research was studied to prepare styrene-methyl methacrylate copolymer sheet （S-co-MMA sheet） by using DPNR （deproteinized natural rubber） as an impact modifier. The DPNR was prepared by adding SDS （sodium dodecyl sulfate） into the HANR （high-ammoniated natural rubber latex） and followed by centrifugation. It was found that DPNR was successfully prepared with the lowest nitrogeneous content about 0.034±0.01% w/w by adding SDS for 1.00 phr and centrifugation at 12,000 rpm. Then DPNR was grafted with styrene and methyl methacrylate （DPNR-g-S/MMA） obtained by emulsion polymerization. The effects of DPNR-g-S/MMA were studied by varied the amount of SDS and redox initiator. From this result the grafting efficiency DPNR-g-S/MMA was higher than that of NR-g-S/MMA. The DPNR-g-S/MMA was used as an impact modifier in S-co-MMA sheet. Furthermore, the appropriate quantities of styrene monomer and DPNR-g-S/MMA were also investigated. While DPNR-g-S/MMA was used as impact modifier in S-co-MMA sheet, the result was shown DPNR-g-S/MMA improve impact strength of S-co-MMA sheet. Scanning electron micrographs of S-co-MMA sheet with DPNR-g-S/MMA was found the smooth fracture surface. Thus impact strength of S-co-MMA/gDPNR sheet was high and physical properties of S-co-MMA/gDPNR sheet could be able to be accepted in industry. Concisely, DPNR-g-S/MMA can be used as an impact modifier in S-co-MMA sheet.

Designing noble metal single-atom-loaded two-dimension photocatalyst for N2 and CO2 reduction via anion vacancy engineering

Building highly active and stable noble metal single atom(MSA)catalyst onto photocatalyst materials for nitrogen reduction reaction(NRR)and CO2 reduction reaction(CRR)is a key to future renewable energy conversion and storage technologies.Here we present a design strategy to optimize the stability and electronic property of noble metal single atoms(MSAs,M=Rh,Pd,Ag,Ir,Pt,Au)catalyst supported on g-C3N4 and 2H-MoS2 photocatalysts towards NRR and CRR.Our results indicate that the MSAs tend to be trapped at the anion-vacancy sites of photocatalyst rather than the pristine photocatalyst surface.This anion vacancy can promise the MSAs with an optimized electron-captured ability in the photoexcitation process,thus decreasing the energy barriers of NRR and CRR on MSAs.Especially,it is revealed that the N-vacancy-stabilized Ir SA on g-C3N4 and the S-vacancy-stabilized RhSA on 2H-MoS2 own the lowest energy barrier in NRR.However,for CRR,the HCOOH is the main product on MSAs supported by gC3N4 and 2H-MoS2.The N-vacancy-stabilized PdSA on g-C3N4 and the S-vacancy-stabilized AuSA on 2H-MoS2 show the lowest energy barrier for HCOOH production in CRR.This finding offers an approach to design specific active MSA centres on photocatalysts by the anion vacancy engineering.

Engineering two-dimensional metal oxides and chalcogenides for enhanced electro-and photocatalysis

Two-dimensional(2D)metal oxides and chalcogenides(MOs&MCs)have been regarded as a new class of promising electro-and photocatalysts for many important chemical reactions such as hydrogen evolution reaction,CO_(2) reduction reaction and N2 reduction reaction in virtue of their outstanding physicochemical properties.However,pristine 2D MOs&MCs generally show the relatively poor catalytic performances due to the low electrical conductivity,few active sites and fast charge recombination.Therefore,considerable efforts have been devoted to engineering 2D MOs&MCs by rational structural design and chemical modification to further improve the catalytic activities.Herein,we comprehensively review the recent advances for engineering technologies of 2D MOs&MCs,which are mainly focused on the intercalation,doping,defects creation,facet design and compositing with functional materials.Meanwhile,the relationship between morphological,physicochemical,electronic,and optical properties of 2D MOs&MCs and their electro-and photocatalytic performances is also systematically discussed.Finally,we further give the prospect and challenge of the field and possible future research directions,aiming to inspire more research for achieving high-performance 2D MOs&MCs catalysts in energy storage and conversion fields.

Silencing of DsbA-L gene impairs the PPARγagonist function of improving insulin resistance in a high-glucose cell model

Disulfide-bond A oxidoreductase-like protein(DsbA-L)is a molecular chaperone involved in the multimeri-zation of adiponectin.Recent studies have found that DsbA-L is related to metabolic diseases including gestational diabetes mellitus(GDM),and can be regulated by peroxisome proliferator-activated receptorγ(PPARγ)agonists;the specific mechanism,however,is uncertain.Furthermore,the relationship between DsbA-L and the novel adipokine chemerin is also unclear.This article aims to investigate the role of DsbA-L in the improvement of insulin resistance by PPARγagonists in trophoblast cells cultured by the high-glucose simulation of GDM placenta.Immunohistochemistry and western blot were used to detect differences between GDM patients and normal pregnant women in DsbA-L expression in the adipose tissue.The western blot technique was performed to verify the relationship between PPARγagonists and DsbA-L,and to explore changes in key molecules of the insulin signaling pathway,as well as the effect of chemerin on DsbA-L.Results showed that DsbA-L was significantly downregulated in the adipose tissue of GDM patients.Both PPARγagonists and chemerin could upregulate the level of DsbA-L.Silencing DsbA-L affected the function of rosiglitazone to promote the phosphatidylinositol 3-kinase(PI3K)-protein kinase B(PKB)/AKT pathway.Therefore,it is plausible to speculate that DsbA-L is essential in the environment of PPARγagonists for raising insulin sensitivity.Overall,we further clarified the mechanism by which PPARγagonists improve insulin resistance.