不同活化过硫酸盐体系深度处理制浆造纸废水研究

采用光-Na₂S₂O₈、热-Na₂S₂O₈、Fe²⁺-Na₂S₂O₈、光/Fe³⁺-Na₂S₂O₈、以及超声-Na₂S₂O₈等5种活化体系对造纸废水深度处理中有机物降解的效果进行了研究,考察了pH、温度、初始Na₂S₂O₈浓度、Fe²⁺浓度、Fe³⁺浓度以及超声频率对造纸废水COD降解的影响。结果表明：5种体系对造纸废水COD降解效率比较为：热-Na₂S₂O₈（84.2%）>光/Fe³⁺-Na₂S...     

CeO2/TiO2吸附剂煤气脱汞产物的浸出规律

基于金属氧化物脱汞吸附剂后续无害化处理要求，本文提出采用硫代硫酸钠(Na₂S₂O₃)溶液浸出金属氧化物脱汞产物的新思路。CeO₂/TiO₂吸附剂(CeTi)吸附汞后得到含汞吸附剂(Hg-CeTi)，利用汞程序升温脱附实验(Hg-TPD)确定其表面吸附态汞的赋存形态。随后探究Na₂S₂O₃溶液对于Hg-CeTi表面脱汞产物的浸出能力，着重分析不同赋存形态的汞在Na₂S₂O₃溶液中的迁移规律。Hg-TPD结果表明，模拟煤气中脱汞产物以HgCl₂、HgO和HgS为主。由于硫代硫酸根(S₂O₃^2-)与Hg²⁺的配合能力，HgO易从Hg-CeTi表面脱附并向液相迁移；HgCl₂会在液相中与OH^-反应生成Hg...     

采用响应面法降低湿法氧化脱硫中Na2S2O3生成量

Na₂S₂O₃是湿法脱硫过程外排废液中最主要的副盐,降低Na₂S₂O₃的生成量对绿色生产具有重要意义。首先采用Plackett-Burman实验筛选出影响Na₂S₂O₃生成量的关键因素,即pH、单质硫浓度、温度。在此基础上运用响应曲面法,以Na₂S₂O₃生成量为目标函数,进行三因素三水平的优化设计分析。研究结果表明,pH对Na₂S₂O₃的影响最大,其次是温度和单质硫浓度,因子间交互作用的影响很小。得到最优的操作条件为pH 8.25,单质硫浓度0.47 g/L,温度31.80℃,PDS浓度90 mg/L,氧硫比1.2 mmol/mmol,此时Na₂S₂O₃生成量为1.838 mmol/L。从Na₂S₂O₃反应动力学和多硫离子的平衡反应两方面对各因素的影响规律进行了解释。最后对实际生产过程进行分析,发现实验得出的pH过低,不利于吸收过程的稳定,现有单质硫熔融分离方法不利于降低脱硫液中的单质硫含量,加速了副盐的生成等问题,对此提出了改进意见,并取得了显著效果。     

添加剂改性Fenton体系中Fe2+再生过程及机制的对比

Fe²⁺的再生直接决定Fenton体系产生的能力。选取羟胺、对苯二酚、对苯醌、亚硫酸钠4种典型添加剂,通过分析不同改性Fenton体系中Fe²⁺浓度、H₂O₂浓度、氧化还原电极电位（ORP）,揭示了Fe²⁺再生机制的差异,并进一步分析了不同添加剂与体系中H₂O₂及·OH的反应情况。结果表明：NH₂OH能快速使Fe²⁺再生,但伴随其消耗,Fe²⁺浓度不断降低。对苯二酚、对苯醌具有相似效果,两者均可大大强化Fe²⁺的再生。与NH₂OH不同,两者在体系中可迅速建立醌循环,持续还原Fe³⁺,且以两种物质或其组合均可建立循环。与上述机理均不同,Na₂SO₃会先与·OH及H₂O₂反应,因而不能有效还原Fe³⁺。实验还发现添加剂均存在与·OH的反应,其中Na₂SO₃还会消耗H₂O₂。     

黄金湿法冶炼含氰废水深度处理工艺比选

针对某黄金冶炼公司冶炼厂含氰废水,采用Na₂SO₃/空气法、Na₂S₂O₅/空气法、H₂O₂氧化法、NaClO氧化法四种工艺进行深度净化。试验确定Na₂SO₃/空气法处理的最佳工艺参数为：反应p H=9、反应时间25 min、Na₂SO₃药剂用量0.1 g/L;Na₂S₂O₅/空气法处理的最佳工艺参数为：反应pH=10、反应时间30 min、Na₂S₂O₅药剂用量0.1 g/L;H₂O₂氧化法处理,H₂O₂药剂用量0.15 g/L;NaClO氧化法处理,NaClO药剂用量0.2 g/L。通过对比分析以上4种处理工艺的成本及优缺点,确...     

煅烧-碱浸法从钒铬还原渣中分离回收钒铬

通过煅烧-碱浸法从钒铬还原渣中分离回收钒铬,考察了煅烧反应过程并探讨了煅烧-碱浸条件对浸出钒的影响。结果表明：煅烧过程中Cr（Ⅲ）和V（Ⅳ） 反应生成中间产物CrVO₄,随后CrVO₄分解为Cr₂O₃和V₂O₅;相同浓度条件下,在V₂O₅浸出效果方面NaOH要优于Na₂CO₃,提高浸出介质浓度和延长浸出时间有利于V₂O₅的浸出,而浸出温度对V₂O₅浸出无明显影响,钒铬还原渣在850℃煅烧1.5 h后经3 mol·L^-1 NaOH在90℃浸出1.5 h,滤渣中的Cr₂O₃质量分数高于96%,钒、铬的浸出率分别为87.3%和小于1%,另外,利用酸性铵盐法能够沉淀滤液中97%的钒。     

Cu2+和Co2+促进芬顿氧化处理垃圾渗滤液的研究

通过在传统芬顿体系中加入Cu²⁺、Co²⁺,研究Cu²⁺/Co²⁺/Fe²⁺/H₂O₂、Cu²⁺/Fe²⁺/H₂O₂、Co²⁺/Fe²⁺/H₂O₂和Fe²⁺/H₂O₂四种芬顿体系对垃圾渗滤液的处理效果,发现当初始pH分别为2、3、4、5、6时,各体系去除CODCr的效果排序为Cu²⁺/Co²⁺/Fe²⁺/H₂O₂>Cu²⁺/Fe²⁺/H₂O₂>Co²⁺/Fe^2...     

光助过硫酸盐氧化处理苯甲羟肟酸的研究

采用紫外光活化过硫酸盐体系降解选矿药剂苯甲羟肟酸,考察了光源、光照强度、氧化剂投加量、pH等因素对苯甲羟肟酸去除效果的影响,并分析讨论了实验机理以及降解产物。结果表明：不同光照条件下,汞灯对苯甲羟肟酸的去除效果比氙灯好,且光照强度越高去除率越高;紫外光照和过硫酸钾(UV/K₂S₂O₈)的共同作用可显著促进苯甲羟肟酸的去除,且苯甲羟肟酸浓度越高去除率越低,过硫酸钾浓度越高去除率越高;pH对UV/K₂S₂O₈降解苯甲羟肟酸的影响较小;常见阴离子(Cl^-、NO₃^-、HCO₃^-)抑制了药剂的降解,阳离子Fe²⁺、Cu²⁺促进了药剂的降解;UV/K₂S₂O₈体系中起主要氧化作用的活性物质是SO₄^·-,苯甲羟...     

离子-有机溶剂复合体系对电子废弃物中贵金属回收研究

以强氧化性的活泼金属离子和络合性有机溶剂结合,制备出离子-有机溶剂复合体系。研究了有机溶剂和金属离子组合类型、氧化剂浓度、反应时间对电子废弃物中贵金属浸出率的影响。结果表明,Fe³⁺(FeCl₃)和乙腈构成的离子-有机溶剂复合体系,通过氧化-络合联合作用对电子废弃物中贵金属的浸出效果最佳;根据对金在体系中的浸出动力学模型分析,反应符合界面化学反应控速(R²=0.963 84);在乙腈加入量为50 mL,FeCl₃浓度为6 mol/L,反应时间24 h条件下,贵金属浸出率98%。     

燃煤电厂脱硫废水预处理软化工艺的试验与优化

燃煤电厂脱硫废水零排放工艺前端需设置预处理段去除悬浮物、钙镁硬度等，以达到后续除盐设备的稳定运行要求。以某电厂生产过程中的脱硫废水作为原水，通过现场批次试验，分析了NaOH+Na₂CO₃、Ca(OH)₂+Na₂CO₃两种软化方式在pH值为10.5时对Mg²⁺、Ca²⁺的去除效果。前者出水Ca²⁺质量浓度能控制在23.20 mg/L,Mg²⁺质量浓度控制在73.65 mg/L;后者出水Ca²⁺质量浓度能控制在16.00 mg/L,Mg²⁺质量浓度控制在7.35 mg/L。采用NaOH+Na₂CO₃组合软化方式形成的污泥约为Ca(OH)₂+Na₂CO₃组合加药方式污泥量的37.95%,但后者沉降速率较高。对于低镁脱硫废水，采用NaOH+Na     

氨法浸出锌冶金渣尘提锌工艺及动力学研究

锌冶金渣尘作为一种重要的锌二次资源,来源广、储量大、具有较高的综合回收利用价值。以NH₃-CH₃COONH₄-H₂O为浸出体系,考察粒度、反应时间、搅拌速度、液固比、总氨浓度、NH₃与NH₄⁺物质的量比和温度对锌浸出率的影响,结果表明：控制浸出温度为25 ℃、总氨浓度为5 mol/L、液固体积质量比为5 mL/g、n（NH₃）/n（NH₄⁺）=1:1、搅拌速度为300 r/min、浸出时间为60 min,在此条件下锌的浸出率可达84%。含锌冶金渣尘浸出动力学分析显示,浸出反应表观活化能为22.66 kJ/mol,锌浸出过程的浸出速率受固体膜层扩散及界面化学反应共同控制,并获得了浸出锌的动力学速率方程。     

硫酸盐熔融反应法从钛铁矿中提取钛的研究

以海南万宁的钛铁矿和硫酸铵为主要原料,通过熔融反应法使钛铁矿中的钛转化为易溶于稀酸的硫酸氧钛,用稀硫酸浸取,达到提高钛浸取率的目的。考察了硫酸铵加入量、焦硫酸钾加入量、反应温度、稀硫酸浸取浓度对钛浸取率的影响。实验结果表明：硫酸铵和焦硫酸钾的加入量、反应温度对钛浸取率的影响较大。提高钛浸取率的最佳条件为：m（钛铁矿）∶m（硫酸铵）∶m（焦硫酸钾）=1∶6∶0.5,反应温度为450 ℃,保温时间为30 min,稀硫酸浸取浓度为2.32 mol/L,在此条件下钛的浸取率达到96.82%。     

臭氧氧化结合硫代硫酸钠溶液喷淋同时脱硫脱硝

采用臭氧氧化结合湿法喷淋硫代硫酸钠溶液的方法开展模拟烟气同时脱硫脱硝实验研究。结果表明,采用臭氧氧化结合Na₂S₂O₃-NaOH溶液湿法喷淋可以实现NO_x和SO₂协同脱除:在O₃/NO摩尔比为1.1～1.2时,溶液中Na₂S₂O₃浓度的增加会提高系统的NO_x脱除效率,烟气中SO₂的存在会促进NO_x的脱除,当SO₂浓度为1030 mg·m^-3、2.0%Na₂S₂O₃溶液作为喷淋液时可实现较高的SO₂脱除效率,同时NO_x脱除效率可达70%以上;喷淋液pH在2.5～9范围内变化时提高浆液pH有利于NO_x的脱除,当pH 9时脱硝效率可达75%。180 min连续同时脱硫脱硝实验结果表明,硫代硫酸钠可有效促进NO_x的脱除,并实现SO₂较高的脱除效率,同时可实现系统同时脱硫脱硝连续稳定运行,喷淋吸收后烟气中NO_x的主要转化产物为NO₂^-, 该方法作为一种有效的同时脱硫脱硝技术,具有一定的工业应用推广前景。     

Degradation of pesticides in water using solar advanced oxidation processes

Alachlor, atrazine and diuron dissolved in water at 50, 25 and 30 mg/L, respectively were photodegraded by Fe²⁺/H₂O₂, Fe³⁺/H₂O₂, TiO₂ and TiO₂/Na₂S₂O₈ treatments driven by solar energy at pilot-plant scale using a compound parabolic collector (CPC) photoreactor. All the advanced oxidation processes (AOPs) employed mainly compared the TOC mineralisation rate to evaluate treatment effectiveness. Parent compound disappearance, anion release and oxidant consumption are discussed as a function of treatment time. The use of Fe²⁺ or Fe³⁺ showed no influence on the reaction rate under illumination and the reaction using 10 or 55 mg/L of iron was quite similar. TiO₂/Na₂S₂O₈ showed a quicker reaction rate than TiO₂ and a similar rate compared to photo-Fenton. The main difference found was between TiO₂/Na₂S₂O₈ and photo-Fenton, detected during atrazine degradation, where pesticide transformation into cyanuric acid was confirmed only for TiO₂/Na₂S₂O₈.     

废旧混合锂电池正极材料还原酸浸行为研究

针对废旧混合锂电池正极材料中有价金属元素镍钴锰的高效分离浸出,设计开发了2种不同混合废料体系：LiCoO₂与Li （Ni_1/3Co_1/3Mn_1/3） O₂、LiMn₂O₄与Li （Ni_1/3Co_1/3Mn_1/3） O₂,研究了还原剂用量、硫酸初始浓度、浸出温度、液固比对浸出过程的影响。LiCoO₂与Li （Ni_1/3Co_1/3Mn_1/3） O₂混合废料较适宜浸出参数为：浸出温度80℃、反应时间90 min、H₂SO₄浓度2.3 mol·L^-1,液固比R=8 mL·g^-1、还原剂Na₂SO₃用量=1.2倍理论量;LiMn₂O₄与Li （Ni_1/3Co_1/3Mn_1/3） O₂组成的混合废料的较适宜浸出实验参数为：浸出温度60℃、反应时间90 min、H₂SO₄浓度2.3 mol·L^-1,R=8 mL·g^-1、还原剂Na₂SO₃用量=1.2倍理论量。得到的浸出规律为混合锂离子电池正极废料回收工艺的广泛适应性提供了参考思路。     

Selective removal of iron(III) from highly salted chloride acidic solutions by solvent extraction using di(2-ethylhexyl) phosphate

Metal ions including Fe³⁺, Ca²⁺, Mg²⁺, Ni²⁺, Co²⁺ and Cu²⁺ are commonly found in the leaching solution of laterite-nickel ores, and the pre-removal of Fe³⁺ is extremely important for the recovery of nickel and cobalt. Di(2-ethylhexyl)phosphate acid (D2EHPA) showed high extraction rate and selectivity of Fe³⁺ over other metal ions. The acidity of the aqueous solution is crucial to the extraction of Fe³⁺, and the stoichiometry ratio between Fe³⁺ and the extractant is 0.86:1.54. The enthalpy for the extraction of Fe³⁺ using D2EHPA was 19.50 kJ/mol. The extraction of Fe³⁺ was ≥99% under the optimized conditions after a three-stage solvent extraction process. The iron stripping effects of different reagents showed an order of H₂C₂O₄>NH₄HCO₃>HCl>NaCl>NaHCO₃>Na₂SO₃. The stripping of Fe was ≥99% under the optimized conditions using H₂C₂O₄ as a stripping reagent.     

Active sites of Cu-ZSM-5 for the decomposition of acrylonitrile

The catalytic decomposition of acrylonitrile (AN) over Cu-ZSM-5 prepared with various Cu loadings was investigated. AN conversion, during which the nitrogen atoms in AN were mainly converted to N₂, increased as Cu loading increased. N₂ selectivities as high as 90–95% were attained. X-ray diffraction measurements (XRD) and temperature-programmed reduction by H₂ (H₂-TPR) showed the existence of bulk CuO in Cu-ZSM-5 with a Cu loading of 6.4 wt% and the existence of highly dispersed CuO in Cu-ZSM-5 with a Cu loading of 3.3 wt%. Electron spin resonance measurements revealed that Cu-ZSM-5 contains three forms of isolated Cu²⁺ ions (square-planar, square-pyramidal, and distorted square-pyramidal). The H₂-TPR results suggested that in Cu-ZSM-5 with a Cu loading of 2.9 wt% and below, Cu⁺ existed even after oxidizing pretreatment. The activity of AN decomposition over Cu/SiO₂ suggested that CuO could form N₂, but, independent of the CuO dispersion, nitrogen oxides (NO_x) were formed above 350 °C. Cu⁺ and the square-pyramidal and distorted square-pyramidal forms of Cu²⁺ showed low activity for AN decomposition. Temperature-programmed desorption of NH₃ suggested that N₂ formation from NH₃ proceeded on Cu²⁺, resulting in the formation of Cu⁺. The Cu⁺ ions were oxidized to Cu²⁺ at around 300 °C. Thus, high N₂ selectivity over Cu-ZSM-5 with a wide range of temperature was probably attained by the reaction over the square-planar Cu²⁺, which can be reversibly reduced and oxidized.     

不同Cu2+浓度下热再生氨电池产电及Cu2+去除特性

热再生氨电池（thermally regenerative ammonia-based battery,TRAB）在废弃资源回收方面展现出独特优势和良好应用前景。通过构建TRAB来处理含Cu²⁺废液并回收电能和铜资源,实验中研究了不同Cu²⁺浓度对电池产电性能和废液Cu²⁺去除效果的影响。研究结果表明,当阴极废液Cu²⁺浓度低于0.2 mol/L时,随着Cu²⁺浓度的增加,电池最大输出功率不断增加,电池输出电压和产电周期不断增加,促使批次获得电量和能量密度也不断增加。同时采用TRAB技术去除废液中铜离子具有较高的去除效率,而且去除率随着废液中铜离子浓度的增加而增加。后续研究采用TRAB结合电凝法的两步处理法有望进一步提高处理效果,具有较好的经济性和应用前景。     

OPTIMIZATION OF LEACHING OF COPPER FROM OXIDIZED COPPER ORE IN NH3-(NH4)2SO4 MEDIUM

Studies were carried out for selective leaching of Cu with simultaneous avoidance of iron dissolution during leaching of oxidized copper ore in an aqueous NH₃-(NH₄)₂SO₄ system. The effects of leaching parameters, such as ammonia concentration, ammonium sulphate concentration, leaching time, and solid-to-liquid ratio, were investigated on leaching of copper. A 2ⁿ factorial experimental design method in the dissolution experiments was used. In addition, the “Steepest Ascent” method was also applied to determine the optimum leaching conditions. It was observed that the most effective parameters on the leaching of copper were ammonia concentration and leaching time. Only 0.17% of iron in ore was dissolved in ammonia and ammonium sulphate medium. The optimum conditions established for maximum copper recovery were: ammonia concentration 2.824 mol L^-1, ammonium sulphate concentration 0.236 mol L^-1, solid-to-liquid ratio 0.167 g mL^-1, leaching time 2 h. Fixed parameters chosen in the experiments were: room temperature, average particle size 2.8 mm, stirring speed 500 rpm. Under the optimum conditions established for maximum copper recovery, the percentage of leached copper was 98.87.