生物滴滤床净化挥发性有机物的研究进展

生物滴滤净化挥发性有机污染物技术是近年发展起来的一项新技术。文章介绍了生物滴滤技术的净化机理、净化效果的影响因素以及国内外研究现状。目前生物滴滤技术需要在以下几方面完善和发展:提高疏水性或难降解废气的处理能力,改进生物滴滤填料性能,提高对各运行参数的控制能力,加强实际废气的净化研究和完善生物滴滤模型。     

硅油对生物滴滤塔处理邻二甲苯废气的影响

研究了硅油对生物法处理有机废气的强化效果。在摇床实验中考察了硅油对邻二甲苯的增溶效果,及其对微生物降解活性的影响情况。结果表明硅油对邻二甲苯有明显的增溶效果且对微生物的活性无影响。在生物滴滤塔挂膜稳定后,考察了加入5%硅油后邻二甲苯在生物滴滤塔中的去除效率变化。相同实验条件下,当进气浓度在600 mg·m-3左右时,硅油可以使邻二甲苯的去除效率明显增加。研究结果显示,添加硅油的生物滴滤塔在去除邻二甲苯废气方面效率更高,去除效率比普通生物滴滤塔高10%左右。根据以上实验结果可以得出结论,硅油能有效提高生物法处理邻二甲苯废气的效果。     

生物法处理挥发性有机废气(VOCs)的研究

生物法处理挥发性有机废气是近年来逐步发展起来的一项废气治理新技术,具有效率高、投资及运行费用低、无二次污染、安全性好等优点。文章主要概述了有机废气生物处理的3种主要形式：生物过滤池、生物滴滤塔和生物洗涤器的原理、流程以及研究进展,比较了以上3种反应器的优缺点,并提出了现存问题和将来的研究方向。     

Development of dissolved carbon dioxide-driven-and-controlled repeated batch fermentation process for ethanol production

We previously observed that as glucose is completely exhausted during ethanol fermentation, the dissolved carbon dioxide (DCO₂) level in the fermenter will suddenly decline. This observation was implemented to design and develop a DCO₂-driven-and-controlled repeated batch fermentation process for ethanol production. The process was tested at four different glucose concentrations (~150 g/L, ~200 g/L, ~250 g/L, and ~300 g/L), and each glucose concentration was controlled under three respective DCO₂ control levels (without DCO₂ control, and DCO₂ controlled at either 1000 mg/L or 750 mg/L). The results show that reported process features complete glucose utilization and is self-driven. For glucose concentration less than 200 g/L, ~41%-50% of fermentation time per batch was saved during the repeated batch operation. It took 12.1 ± 1.1 hours-14.9 ± 1.9 hours to complete a batch with glucose feed at ~250 g/L and 21.7 ± 6 hours-31.5 ± 7 hours to complete a batch with glucose feed at ~300 g/L. The reported process is time saving and stable, but the ethanol yield is ~20% lower than the operation without DCO₂ control. Dissolved CO₂ control became essential for glucose concentrations greater than 250 g/L if zero glucose discharge in each batch during the operation is desired.     

Coupling ultraviolet photolysis and biofiltration for enhanced degradation of aromatic air pollutants

Coupling UV photolysis and biofiltration was evaluated as an effective treatment strategy for the enhanced degradation of hardly biodegradable aromatic volatile organic compounds (VOCs). o‐Xylene, a recalcitrant and poorly water‐soluble VOC, was used as a model compound and treated in two parallel treatment systems with and without UV pretreatment. Contaminated streams with flow rates of 0.186–0.384 m³ h^?1 and inlet o‐xylene concentrations of up to 0.22 g m^?3 were passed through the treatment system. About 20% (between 10 and 35%) of o‐xylene was converted into water‐soluble intermediates during the UV photolysis stage, which partially oxidized o‐xylene to more water‐soluble and biodegradable byproducts. The untreated contaminant along with the byproducts of UV photolysis was then removed effectively in the biofiltration stage, with improvements of up to 100% compared with the control biofiltration process. The results suggested that combined UV photolysis–biofiltration is promising as an effective technique to eliminate hydrophobic and recalcitrant organic compounds from contaminated air steams. Copyright © 2005 Society of Chemical Industry     

Extraction of phospholipids from canola with supercritical carbon dioxide and ethanol

The potential use of supercritical (SC)-CO₂/ethanol mixture for the extraction and fractionation of phospholipids (PL) from flaked canola seeds, canola meal, and acetone insolubles (AI) was investigated. PL extraction was possible when ethanol was used as a cosolvent in SC-CO₂. PL recovery of 20.8% was achieved when canola flakes were extracted at 70°C and 55.2 MPa with SC-CO₂/10%EtOH after iol removal with neat SC-CO₂. Soaking of canola meal with ethanol prior to SC-CO₂/EtOH extraction increased PL recovery to 30.4%. PL content of the extracts increased with decreasing triglyceride concentration in the feed material and increasing amounts of ethanol added to SC-CO₂ or used for soaking. Fractionation of Al gums resulted in extracts containing 50% PL, of which 90% was phosphatidylcholine (PC); but yields were low, even after soaking treatment, due to caking. SC-CO₂/EtOH mixture may be used to extract PC-enriched PL from flaked canola seeds, canola meal, and AI. However, further research is needed to improve extraction efficiency.     

Improved design and optimization models for the fixed bed adsorption of acid dye and zinc ions from effluents

The bed depth service time (BDST) design model, which accounts for the change of bed adsorption capacity with service time, has been modified to expand its application and overcome the limiting assumptions of the original BDST analysis. Column experiments were undertaken to test the new model for two adsorption systems, namely zinc ion–bone char and Acid Blue 80 dye‐activated carbon. It was found that the percentage of saturation capacity could be correlated using a square‐root dependence on the service time and this correlation was incorporated into the original BDST analysis to replace the total sorption capacity term, giving the model a much wider application to real systems. The empty bed residence time optimization approach was modified using the same time‐dependent capacity expression and was successfully applied to the metal ion–bone char and the dye‐activated carbon system with the use of equilibrium saturated bed capacity. These modifications to the BDST design model and the EBRT optimization model will give more accurate scale‐up data for the design of large‐scale column adsorption systems. © 2002 Society of Chemical Industry     

氮和磷对生物滴滤塔净化煤矿乏风瓦斯的影响

研究了氮源类型和浓度以及磷元素浓度对生物滴滤塔净化极低浓度CH4的影响。利用空气和高纯CH4混合气模拟煤矿乏风瓦斯,生物滴滤塔填料为陶瓷鲍尔环,以实验室分离筛选到的甲烷氧化菌进行接种挂膜。结果表明,进气流量为2 L?min?1,喷淋液流量为0.1 L?min?1,进气CH4浓度在0.1%~1.1%,以Na NO3为氮源时,生物滴滤塔净化CH4的效果最好,优于(NH4)2SO4和NH4NO3为氮源时的表现。喷淋液中Na NO3浓度为70 mmol?L?1,进气CH4浓度为0.1%~1.1%时,生物滴滤塔的CH4去除负荷为10.67~39.72 g?m?3?h?1,去除负荷随CH4浓度增加而增加;CH4净化率为97.92%~39.70%,净化率随CH4浓度增加而下降。在最佳氮源条件下,进气CH4浓度为0.9%,P元素浓度为100 mmol?L?1时,滴滤塔CH4去除负荷最大为49.69 g?m?3?h?1,CH4净化率60.90%。     

车用胶粘剂对车内空气质量的影响

以车用胶粘剂作为研究对象,重点探讨了其VOC(挥发性有机物)含量和气味性能对车内空气质量的影响,并提出了相应的改善措施。研究结果表明:焊装用胶的主要成分为丁基橡胶、加工油和炭黑,三者对VOC含量的影响依次为加工油>炭黑>丁基橡胶,其气味等级(3～4级)属于难闻和反感级别;涂装用胶的主要成分为糊状PVC(聚氯乙烯)树脂、DOP(邻苯二甲酸二辛酯)增塑剂和有机溶剂等,其对整车车内VOC含量影响较大,并且涂装用胶的气味等级(4级)属于反感级别;总装用胶的主要成分为异氰酸酯、聚醚多元醇等,其乙苯含量相对最高,对整车车内的VOC含量影响极大,并且总装用胶的气味等级(1级)属于无法忍受级别。     

含氯挥发性有机物的催化氧化研究进展

催化氧化是控制挥发性有机污染物排放的有效途径之一,但传统催化剂在氧化消除含氯挥发性有机物(CVOCs)时易中毒而失活,因此,研发新型、高效、稳定的催化剂对其工业应用具有重要意义。简要综述近年来稀土及过渡金属氧化物、分子筛和负载贵金属催化剂对CVOCs氧化的催化性能和催化反应机理,剖析CVOCs氧化反应副产物的形成和催化剂失活的原因,并展望CVOCs催化氧化技术的未来发展趋势。     

低VOCs含量的PET/TiO2@Ag共混体系的研究

以熔融共混与负载银(Ag)的方法制备聚对苯二甲酸乙二醇酯(PET)/二氧化钛@银(TiO2@Ag)共混体系,并通过差示扫描量热仪(DSC)、电子万能材料试验机和可见分光光度计等对共混体系的热性能、力学性能和光催化性能进行研究与分析。结果表明,在纳米TiO2含量为3%(质量分数,下同)时,共混体系的热性能与力学性能最优;Ag的负载能够显著拓宽PET/TiO2@Ag共混体系的光响应范围;随着Ag负载量的增加,共混体系的光催化性能呈先升高后降低的趋势,且在光照时间为4 min时其光催化性能最优,同时共混体系的挥发性有机物(VOCs)的含量呈先降低后升高的趋势,且在光照时间为4 min时,其VOCs含量达到极小值。     

非均匀布风流化床内大颗粒停留时间特性

试验考察了非均匀布风配置对大颗粒在倾斜布风板流化床内停留时间分布的影响规律。结果表明,排渣管风速增加,E(t)曲线变平、波动增加,平均停留时间(MRT)呈指数增长;高风速区风速升高,先是分离过程占优,后转变为返混能力占优,MRT先减后增,存在一个适宜于分离的运行风速窗口;低风速区风速加快,混合能力增强,MRT变长。此外,还探讨了物性参数的影响。示踪物球形度越高、表面越光滑,越有利于分离,MRT变短。而尺寸的影响则与密度相关,对于重质示踪物,尺寸增加,MRT变短;而对于轻质示踪物,尺寸变大,MRT变长。试验所得停留时间分布(RTD)曲线形状、波峰时刻、峰值、波动等信息能够充分反映床内的颗粒流动与混合过程;对于内循环流动机理的探索、多组分流化床的工程应用具有一定的参考意义。     

二氧化碳直接空气捕集材料与技术研究进展

直接空气捕集（DAC）等新兴负碳排放技术是实现“双碳”目标的托底技术保障,近年来受到广泛关注。本文简要分析了直接空气碳捕集技术的特性,归纳总结了胺功能化无机材料和聚合物、金属氢氧化物和碳酸盐、多孔材料等痕量二氧化碳捕集性能,初步分析了负载方式、载体结构等与吸附容量和动力学的关系。浅析了该领域发展面临的问题和机遇,从能耗和性能方面对捕集材料和技术的研发提出以下建议：相较于物理吸附材料,胺功能化材料和固体碱等化学吸附材料具有更好的应用前景;在工艺开发领域,可以借鉴其他低浓度气体深度脱除工艺的经验;另一方面,可以结合不同工艺优势,设计多种工艺耦合的流程;最后,在严峻的环境问题下,必须加快材料研发的步伐,未来的研究重点应集中在材料的设计和低能耗再生方式的开发上。     

含微细颗粒的挥发性有机废气综合治理技术研究开发

工业的发展，带来了很多丰闷关的环境污染问题。挥发性有机物（VOcs）是常见的污染物，对环境、动植物的生长及人类健康造成了极大的危害，因此越来越受到世界各国的重视，许多发达国家都颁布了相应的法令，限制VOCs的排放。含微细颗粒的挥发性有机废气由于多种物质成份并存，特别是橡胶行业炼胶废气一直是环保治理的难点。我们提出采用“预处理除油装置＋活性炭流动床吸附＋布袋除尘器＋活性炭固定床吸附装置”的处理方式，能有效治理这类废气，尤其是针对橡胶行业炼胶废气，具有处理效率高、运行稳定、运行费用低、操作简便等特点。     

TiO2光催化降解气相有机物的研究进展

介绍了近年来TiO2光催化降妥气相中含氯有机物。芳香族有机物。链烃及含氧,含硫,含氮等有机物的研究现状和进展。并对TiO2光催化降解气相有机物关键技术进行了分析。对其应用前景进行了展望。     

二氧化碳联合核桃壳提取液促进单针藻Monoraphidium sp. QLZ-3的生长和油脂积累

以单针藻Monoraphidium sp. QLZ-3为对象,研究了CO₂对微藻在核桃壳提取液（walnut shell extracts,WSE）中生长及油脂积累的影响。结果显示,在12%的CO₂条件下,微藻在WSE中的生物量产率及油脂产率达到196.85mg/(L·d)和97.52mg/(L·d),分别是对照组的1.33倍和1.57倍。WSE培养下,外源CO₂上调了微藻中核酮糖1,5-二磷酸羧化酶基因（ribulose 1,5-bisphosphate carboxylase/oxygenase,rbcL）的表达量,从而促进了CO₂的固定。此外,12% 的CO₂提高了微藻对WSE中多酚的利用,同时上调了乙酰辅酶A羧化酶（acetyl coenzyme A carboxylase,ACCase）和苹果酸酶（malic enzyme,ME）活性,下调了磷酸烯醇式丙酮酸羧化酶（phosphoenolpyruvate carboxylase,PEPC）活性。研究表明,CO₂可以提高WSE中微藻的生物量产率和油脂产率,降低培养成本,为核桃壳的资源化利用及微藻的工业化生产提供了新的理论基础。     

催化湿式氧化法处理噻螨酮生产废水的试验

采用CuO-MnO2-La2O3为催化剂,以催化湿式氧化技术处理噻螨酮生产过程中产生的的高浓度有机废水.试验结果表明,用该复合催化剂在处理此种有机废水时表现出较好的催化活性.在230℃,氧气分压为2.5MPa和pH值为7.3的条件下,当废水CODCr的质量浓度为15 730 mg/L,在120 min内,CODCr去除率达到96.1%,而在相同条件下未加催化剂的湿式氧化CODCr去除率只有50.3%.     

低VOC含量的PET/PAAS/活性炭复合材料的制备及性能研究

通过机械共混法制备了聚对苯二甲酸乙二醇酯（PET）/聚丙烯酸钠（PAAS）/活性炭复合材料,并通过差示扫描量热仪（DSC）、X射线衍射仪（XRD）和高效液相色谱仪（HPLC）对复合材料的热性能、晶体结构和挥发性有机化合物（VOC）含量等进行研究与分析。结果表明,活性炭的加入能提高PET/PAAS/活性炭复合材料的结晶度,降低复合材料中的VOC含量;随着活性炭的加入,PET/PAAS/活性炭复合材料的熔点先降低后升高,断裂强度呈先升高后降低,且分别在活性炭添加量为0.75 %与0.2 5%时达到最大值;当活性炭含量为1.25 %时,复合材料的甲醛去除率达到94.4 %,乙醛去除率达到92.1 %,丙酮去除率达到80.2 %。     

浅析蓄热式热力氧化技术处理挥发性有机废气

VOC是一种对环境和人类产生严重危害的废气,概述了VOC废气的来源和危害,同时介绍了一种很有发展前景的VOC废气处理方法——蓄热式热力氧化技术。