SECONDARY CLEANUP OF TRUEX PROCESS SOLVENT

Several secondary cleanup procedures have been tested for hydrolytically and radiolytically degraded TRUEX process solvent (0.2 M. n-octyl(phenyl)N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO)-1.2 M tributylphosphate (TBP) in n-dodecane). Sodium carbonate scrub was used as primary cleanup. For the secondary cleanup macroporous anion exchange resins and other solid adsorbents, such as goethite (a-FeOOH), alumina and activated charcoal were used. The effectiveness of a cleanup procedure was established by its capability to restore the original americium(III) distribution ratio from low HNO₃ concentration, that is characteristic of pristine process solvent. Further information was obtained from the measurement of up to seven successive AmfJIT) distribution ratios with the regenerated solvent, using the stripping conditions of the TRUEX process. Although all the procedures tested proved to be effective in removing most of the unwanted acidic products from the degraded solvent, the use of a strong base macroporous anion exchange resin, acid washed activated charcoal and acid washed alumina were particularly successful.     

Sialon陶瓷注射成型的溶剂脱脂研究

在Sialon陶瓷注射成型中,以蜡基粘结剂的溶剂脱脂为研究对象,考查了注射成型中溶剂脱脂工艺的脱脂温度、脱脂时间、试样厚度、溶剂加入方式及表面积与体积之比等参数对试样脱脂的影响,对溶剂脱脂过程中可溶组元的最大脱除率作了初步的分析,并用SEM观察了不同脱脂率的形貌的变化。结果表明：在40℃下采用纯的三氯乙烯对试样进行脱脂,当PW的脱出率在75%以上时,连通孔道基本形成,坯体在后续热脱脂和烧结中不会变形。     

预分散溶剂萃取平衡与传质特性

预分散溶剂萃取(predispersed solvent extraction,简称PDSE）是一种新型的液-液萃取方法.该过程首先将溶剂制成胶质液体泡沫(colloidal liquid aphron ,简称CLA),同时借助胶质气体泡沫(colloidal gas aphron,简称CGA)实现溶质的分离.本文以磷酸三丁酯（TBP）-煤油为溶剂,以十二烷基苯磺酸钠（SDBS）为水相表面活性剂,以TWEEN 80为油相表面活性剂制备了胶质液体泡沫（CLA）. 用十六烷基三甲基溴化胺（HTAB）为水相表面活性剂制备了胶质气体泡沫（CGA）. 利用半间歇式PDSE过程萃取苯酚溶液.研究了pH值、表面活性剂浓度、相比等对萃取率和平衡分配系数的影响.实验发现,PDSE过程更适用于小相比（油相∶水相为1∶1000或更小）和极稀溶液的萃取.实验还发现, PDSE过程的萃取率随着CLA中TBP浓度的增加而增加, 随相比的增加而提高.利用刚性球模型计算了CLA的传质系数,并与传统的液滴进行了比较.在相同的粒径下,CLA比传统的液滴具有更高的分散相总传质系数;与传统萃取塔中存在的液滴相比,CLA也具有一定的优势.此外,对于两者K_da的比较,更体现了CLA的优越性.     

溶剂法氢化松香生产过程中溶剂变化的原因分析

溶剂法氢化松香生产过程中,循环使用的溶剂总量变化不大,但其轻组分因更容易挥发而在生产过程的各个环节流失,含量会逐渐降低;而在加氢反应的温度和氢化松香的蒸馏条件下,松香中的部分重油和少量松香脱羧产物被分离出来进入溶剂,造成重组分含量逐渐增加。溶剂的变化是影响氢化松香质量的一个因素。     

膜萃取防止溶剂污染的优势

本文以３％ＴＢＰ／苯酚／水为实验体系在不同的膜器中对膜萃取过程中料液对萃取剂的夹带,即溶剂的二次污染进行了研究。在保持膜两侧压降不变的情况下对进口和出口处料液的ＣＯＤ值进行了测定,并与传统的溶剂萃取方法相比较。结果表明,膜萃取中料液中溶剂只有少量的夹带,并且夹带量与操作条件和膜构件基本无关。     

酚醛树脂复合材料热降解过程的研究

利用热重分析法对碳纤维增强S-157酚醛树脂在氮气和空气气氛下的热降解过程进行分析,研究了热降解气氛、升温速率与材料热降解温度、残炭率之间的关系,以及对其烧蚀性能的影响,并求得该复合材料的热降解活化能,分析其热降解机理,为烧蚀防热复合材料的热性能评价提供一种研究方法。     

SIMULATION OF A THREE PHASE REACTOR FOR THE SOLVENT METHANOL PROCESS

Single pass conversions in conventional vapor phase methanol synthesis are low, necessitating recycle of large quantities of unconverted reactants. In the Solvent Methanol Process (SMP), the use of an inert and highly selective solvent in the synthesis loop enables the removal of methanol as soon as it is formed and helps overcome equilibrium limitations that exist in the vapor phase process. An industrial scale, packed bed, adiabatic reactor with cocurrent upflow of synthesis gas and solvent has been simulated for the SMP. The simulation shows that very high single pass conversions of CO and H₂ are attainable such that recycle can be eliminated. Reaction rates are however lower than vapor phase rates due to pore diffusion limitations.     

溶剂萃取法回收与处理含DMAc废水的研究

本文研究了用低沸点萃取剂处理和回收含二甲基乙酰胺（DMAc)废水的可行性及工艺条件，经研究表明，在常温20－35℃时，用氯仿萃取二甲基乙酰胺，当溶剂与水相体积比为2：1时，经六级逆流萃取，可将废水中20％（w/w)的二甲基乙酰胺含量降至300mg/L以下。废水的pH值对萃取效率有明显的影响，当废水的pH值较大，即偏碱性对萃取有利。     

表面活性剂废水的电催化氧化及降解动力学

采用电催化氧化法处理较低浓度的表面活性剂废水,考察了反应时间、体系pH值、表面活性剂初始浓度、电流密度等因素对处理效果的影响,并初步探讨了表面活性剂降解的反应动力学.结果表明,当初始pH值为7.5,反应时间为120mm时,质量浓度为25mg/L的表面活性剂十二烷基苯磺酸钠(DBs)的去除率为97%,且DBS降解的反应动力学模型可用幂指数方程描述,该模型计算值与试验值吻合较好,误差在7%以内.另外,该方法耐冲击负荷能力强、pH 值适用范围广,有较好地应用前景.     

TiO2体系对酸性红B的催化超声降解过程的影响

采用处理过的市售的锐钛型和金红石型纳米TiO2作为声催化剂,低功率的超声波作为激发源,研究了纳米TiO2对酸性红B催化超声降解过程的影响.结果表明:锐钛矿纳米TiO2和金红石型纳米TiO2对酸性红B有着不同的超声降解过程.锐钛型纳米TiO2以空穴氧化为主,使酸性红B脱色和降解过程同时进行,而金红石型纳米TiO2则以自由基氧化为主,是先脱色后降解.锐钛型纳米TiO2降解效果明显优于金红石型纳米TiO2.单纯超声照射下酸性红B没有明显的脱色和降解过程发生.因此,锐钛型纳米TiO2催化超声降解有机污染物的方法具有很好的应用前景.     

PX氧化过程中HAc的溶剂效应及其分解动力学

论述了对二甲苯氧化过程中,溶剂醋酸对催化活性络合物的形成和对反应转化率以及对产物对苯二甲酸收率和质量的影响。利用示踪醋酸分子,系统考察了催化剂Co/Mn配比、原料对二甲苯和促进剂溴浓度以及通氧速度对醋酸分解动力学和机理的影响。得出了氧化最佳工艺条件为:①在Co-Mn-Br催化体系中,Mn的浓度为5—10%,[Br]/[Co+Mn]=2-4;②在反应液中,[PX]=1.2-1.8mol/L,亦即[HAc]/[PX]=3.5-5.4;③通空气速度V_(空气)>46L/(h·kg)。     

溶剂萃取法制备农用硝酸钾

通过实验研究确立了溶剂萃取法制备硝酸钾的新的工艺流程,并优化了操作条件。在所确定的主要条件下,用溶剂Ⅰ、Ⅱ进行低温萃取,可得到氯含量较低的农用硝酸钾产品,经精制可得工业用产品。     

OPTIMIZATION OF PHOTOCATALYTIC PROCESS PARAMETERS FOR THE DEGRADATION OF 2,4,6-TRICHLOROPHENOL IN AQUEOUS SOLUTIONS

In the present study, the photocatalytic degradation of 2,4,6-trichlorophenol (2,4,6-TCP) was carried out in a batch reactor under UV light in aqueous solution for 5 h using titania P-25 (surface area 50 m²/g) as a photocatalyst and sodium hypochlorite as an oxidant. Variables studied include catalyst dose (0.25–1.25 g/L), pH (2–6), and concentration of the oxidant (3.06 × 10^?6M–15.3 × 10^?6M). The rate of degradation was studied in terms of changes in concentration of the pollutant and reduction in chemical oxygen demand. The optimal values of operational parameters leading to 2,4,6-TCP abatement were obtained by using response surface methodology. The percent degradation and COD reduction of 2,4,6-TCP was found to increase with increases in the catalyst dose up to the dose of 1.1 g/L, pH in the range of 4–4.5, and oxidant concentration of 9.95 × 10^?6M.     

OPTIMIZATION OF PHOTOCATALYTIC PROCESS PARAMETERS FOR THE DEGRADATION OF 2,4,6-TRICHLOROPHENOL IN AQUEOUS SOLUTIONS

In the present study, the photocatalytic degradation of 2,4,6-trichlorophenol (2,4,6-TCP) was carried out in a batch reactor under UV light in aqueous solution for 5 h using titania P-25 (surface area 50 m²/g) as a photocatalyst and sodium hypochlorite as an oxidant. Variables studied include catalyst dose (0.25-1.25 g/L), pH (2-6), and concentration of the oxidant (3.06 × 10^-6M-15.3 × 10^-6M). The rate of degradation was studied in terms of changes in concentration of the pollutant and reduction in chemical oxygen demand. The optimal values of operational parameters leading to 2,4,6-TCP abatement were obtained by using response surface methodology. The percent degradation and COD reduction of 2,4,6-TCP was found to increase with increases in the catalyst dose up to the dose of 1.1 g/L, pH in the range of 4-4.5, and oxidant concentration of 9.95 × 10^-6M.     

超声曝气组合工艺降解采油废水黄原胶的研究

以超声波清洗机和空气泵构成超声曝气组合工艺降解采油废水中黄原胶的反应系统,单因素考察了反应时间、通气量、超声功率.黄原胶溶液初始浓度以及pH等因素对黄原胶降解效率的影响;并选取黄原胶溶液的pH、超声功率、通气量和时间进行了正交试验.结果表明,各种因素对黄原胶降解的影响先后为:初始pH、通气量、时间、超声功率;在pH为2、曝气量为870L.b-1、超声功率为300W以及时间75 min时,废水黄原胶粘度降低可达到97.28%.     

纳米TiO2可见光催化-SBR组合工艺降解制药废水

以絮凝为预处理和后续处理工艺,以"纳米TiO2可见光催化-SBR"为组合主体工艺处理制药废水。通过对组合工艺1(絮凝、光催化、SBR、絮凝、出水)和组合工艺2(SBR、絮凝、光催化、絮凝、出水)处理制药废水效果的比较分析可知,组合工艺1的处理效果要高于组合工艺2,主要是因为TiO2光催化预处理反应不仅可以去除一定量的COD,降低原制药废水的负荷,还可有效改善原废水的可生化性和生物毒理性,为后续SBR生物处理提供适宜的处理水质。对光催化降解制药废水的动力学研究表明,光照强度越高,其光催化降解反应遵循二级反应动力学,随着光照强度的减弱,其光催化降解反应趋向于三级反应动力学。     

PURIFICATION OF WET PROCESS PHOSPHORIC ACID BY SOLVENT EXTRACTION WITH PROPYL ETHERS.

The distribution data for the impurities (SO⁼ ₄, F^?, Fe, Al and Mg) during purification of wet phosphoric acid (WPA) with di-n-propy1 ether (DPE), di-n-propy1 ether containing 6. 5% of the isomer n-propylriso-propyl ether (DPE(M)) and di-iso-propyl ether (DIPE) at 25°C are reported. The distribution of phosphoric acid (PA)(SO⁼ ₄, F^?, Fe, Al and Mg between the conjugated phases has been investigated. The system W-WPA-DIPE shows a three-liquid-phases-at-equilibrium zone with 65.7% of phosphoric acid in the aqueous phase, 43.9% in the heavy organic phase and 4.3% in the light organic phase. The degree of purification increases, for the three solvents studied, when decreasing the PA concentration in the organic phase (except for F^?when using DPE}. Purification data for iso-arayl alcohol (1) and these three solvents are compared, showing that di-n-propyl ether with 6.5% of the isomer propyl-iso-propyl ether is the best solvent (from all solvents investigated in these series) for the purification of the wet process phosphoric acid studied.