气相色谱与热脱附联用测定环境空气及无组织排放工业废气中三氯乙烯

建立了热脱附仪和气相色谱联用测定环境空气及无组织排放工业废气的三氯乙烯分析方法，该方法的检测限为〈0．054μg，当采样体积为13．5L时，方法的最低检出浓度为0．004mg／m^3。在所选定的操作条件下，对400ng三氯乙烯标准进行重复6次的测定，所得的相对标准偏差低于11．0％。该方法已用于环境空气和无组织排放工业废气的测定，取得令人满意的结果。     

两段反应串联的二氯乙烷、氯化氢氧氯化制三、四氯乙烯

为高效、环保地生产三、四氯乙烯,同时解决副产氯化氢的出路问题,通过对二氯乙烷氧氯化制三、四氯乙烯反应体系的剖析,提出以氯化氢为氯源的两段反应串联新工艺。在第1段中仅仅发生氯化氢氧化反应,第2段中二氯乙烷与生成的氯气及未反应完的氧气发生一系列氧氯化反应制三、四氯乙烯。该工艺有效避免了二氯乙烷及其他有机氯的深度氧化;而且采用该工艺,每一段可采用不同的催化剂和不同的反应条件,以适应不同的反应需求。第2段采用的催化剂是在第1段采用的负载于Y分子筛的Ce-Cu-K复合催化剂基础上改性优化而成,适宜的钾铜质量比为0.73;当催化剂活性组分负载量达到45.5%时,三、四氯乙烯收率最优。同时对第2段反应条件进行了优化,结果表明适宜的工艺条件为:反应温度430℃,二氯乙烷重时空速0.5 h^-1,二氯乙烷、氯化氢与氧气三者的进料摩尔比1:2.4:1.8;此时三、四氯乙烯收率最高可达83.4%,有机氯的总收率可达96.1%。反应结果较单段氧氯化反应工艺显著提升,具有良好的工业应用前景。     

Surfactant‐Enhanced Regeneration of Polymeric Resin in a Vapor‐Phase Application

Abstract

Surfactant enhanced carbon regeneration (SECR) was employed to regenerate a polymeric resin saturated with trichloroethylene (TCE), using an aqueous solution of the anionic surfactant sodium dodecyl sulfate (SDS). More than 95% of the sorbed TCE was removed in the desorption operation with a 0.1 M SDS solution at a superficial flow rate of 1 cm/min. The desorption rate of TCE from pores of the resin is limited by the concentration of SDS in the regenerant and its flow rate. From the breakthrough curve of the subsequent adsorption cycle without a flushing step following the desorption, only 40% of the effective adsorption capacity of the virgin resin is observed for the regenerated resin. With a water flushing step following the surfactant regeneration step, the effective adsorption capacity is significantly improved to about 60% of that of the virgin resin. Thermal gravimetric analysis indicates that the reduction in the effective adsorption capacity of regenerated resin resulted from the residual SDS remaining in the pores of the resin. The regeneration step is equilibrium limited whereas the water flushing step is rate limited under the studied conditions. Despite the loss of subsequent cycle adsorption capacity, SECR may still be economical as an in‐situ, low temperature regeneration method.     

响应曲面法优化改性漂珠对水中三氯乙烯的吸附性能

本文对工业废弃物漂珠进行煅烧改性,制备易回收的吸附材料。以三氯乙烯作为目标污染物,研究改性漂珠吸附污染物的可行性和不同改性参数对去除污染物的影响。通过Box-Behnken设计-响应曲面法以煅烧温度、煅烧时间及粒径为影响因素,建立以三氯乙烯吸附量为响应值的预测模型,对改性漂珠进行XRD、SEM-EDS、BET等表征分析以探讨材料的吸附性能。结果表明,煅烧改性后的漂珠表面疏松多孔,比表面积增大2.4倍左右,影响改性漂珠吸附水中三氯乙烯的因素顺序依次为:煅烧时间＞煅烧温度＞粒径。模型优化的最优吸附条件为:粒径为0.25~0.38 mm,煅烧温度为640 ℃,煅烧时间为80 min,预测吸附最大值为1 326 μg/g,试验值为1 344 μg/g,两者仅相差1.4%。通过高温煅烧改性的漂珠具备更优良的吸附性能,是一种可大规模生产、以废治废、易回收的环保材料。     

废水中微量三氯乙烯含量的测量

用适量的二氯甲烷提取出废水中的微量三氯乙烯(TCE),然后对萃取液进行气相色谱分析,得出萃取液中三氯乙烯的含量,换算出废水中的三氯乙烯含量。此方法的检测下限为0.5 mg/L。     

Ru-Promoted CrO x /Al2O3 Catalyst for the Low-Temperature Oxidative Decomposition of Trichloroethylene in Air

A series of Ru-promoted CrO _x /Al₂O₃ as catalysts for the low-temperature oxidative decomposition of trichloroethylene (TCE) were characterized and evaluated in comparison with an unpromoted CrO _x /Al₂O₃ catalyst. Catalyst characterization was conducted by surface area measurement, X-ray diffraction and X-ray photoelectron spectroscopy. Catalyst performance in the TCE decomposition reaction was evaluated with respect to the initial catalytic activity, the rate of catalyst deactivation, and the product concentrations of CO and Cl₂ under dry or wet air conditions. The presence of a small amount of Ru, as much as 0.4 wt% in a CrO _x /Al₂O₃ catalyst, brought about several beneficial effects on the catalytic reaction performance. As compared with the unpromoted CrO _x /Al₂O₃, this Ru-promoted CrO _x /Al₂O₃ catalyst showed enhanced catalytic activity (249 versus 264 °C in terms of temperature at which 50% of TCE conversion occurred), a reduced concentration of CO (180 versus 325 ppm) in the product, and a decreased propensity to deactivation. Performance improvements of the Ru-promoted CrO _x /Al₂O₃ catalyst were thought to originate from its enhanced oxidation activity due to the coexisting highly-dispersed Ru oxides rendering less active Cr(III) to more active Cr(VI), and facilitating the process of supplying activated oxygen for the reaction system.     

C_2HCl_3气相O_3氧化反应动力学

在间歇循环气相反应器中研究了C_2HCl_3在101.3 kPa和 298 K下O_3氧化动力学.对实验结果回归分析表明,总的反应级数是2.5级,O_3和C_2HCl_3级数分别为1级和1.5级,平均反应速率常数为57.3 mol~(-1.5)·L~(1.5)·s~(-1)     

负载纳米零价铁／钯（ZVI／Pd）双金属活性炭去除水中三氯乙烯（TCE）的研究

使用“初湿含浸法”将纳米级零价铁,钯（ZVI／Pd）颗粒负载于颗粒活性炭（GAC）上,考察制得的反应性活性炭（RAC）去除地下水中三氯乙烯（TCE）的有效性。研究发现,在制得的RAC中零价铁以纳米颗粒的形式负载其上,粒径范围在50～100nm之间,其负载量具有上限,一般低于30％。相比于GAC,RAC的BET比表面积有一定程度的下降。RAC上的铁成分主要以非晶态的形式存在,具有较高的分散度。通过批式试验发现,RAC能够快速有效降低水中TCE浓度,其去除动力学符合伪一级动力学模型。萃取试验和氯离子检测结果表明,RAC在吸附TCE的同时可以对其进行还原脱氯,在48h内不同RAC对于吸附其上的TCE的脱氯比例可达14．5％-30．4％。RAC对于水中TCE的去除能力短期内以吸附为主,铁含量的增加不利于其对于TCE的吸附但会有助于增加长期TCE的还原降解量。RAC在不同溶解氧环境下对TCE的去除性能优良,在短期内并没有太大区别;但若经过大量好氧（DO=6．9mg/L）的纯水浸泡,表面零价铁颗粒可能逐渐腐蚀。     

三氯乙烯生产中废弃物的处理

对三氯乙烯生产中的废弃物进行处理,1t废弃物处理后产出900 kg三氯乙烯.介绍了处理工艺.