废钯催化剂中钯的回收

介绍了利用废钯催化剂制备氯化钯的方法,研究了液碱浓度以及液碱用量对溶解过程中残留物含量的影响,以及王水浸出过程中硝酸残留量对钯回收率的影响。通过对影响因素的考察,确定最佳条件,钯的总回收率可达93%以上。     

Sunlight-driven reduction of silver ion to silver nanoparticle by organic matter mitigates the acute toxicity of silver to Daphnia magna

Due to the unique antibacterial activities, silver nanoparticles (AgNPs) have been extensively used in commercial products. Anthropogenic activities have released considerable AgNPs as well as highly toxic silver ion (Ag⁺) into the aquatic environment. Our recent study revealed that ubiquitous natural organic matter (NOM) could reduce Ag⁺ to AgNP under natural sunlight. However, the toxic effect of this process is not well understood. In this work, we prepared mixture solution of Ag⁺ and AgNPs with varied Ag⁺% through the sunlight-driven reduction of Ag⁺ by NOM and investigated the acute toxicity of the solutions on Daphnia magna. Formation of AgNPs was demonstrated and characterized by comprehensive techniques and the fraction of unconverted Ag⁺ was determined by ultrafiltration-inductively coupled plasma mass spectrometry determination. The formation of AgNPs enhanced significantly with the increasing of solution pH and cumulative photosynthetically active radiation of sunlight. The toxicity of the resulting solution was further investigated by using freshwater crustacean D. magna as a model and an 8 hr-median lethal concentration (LC₅₀) demonstrated that the reduction of Ag⁺ by NOM to AgNPs significantly mitigated the acute toxicity of silver. These results highlight the importance of sunlight and NOM in the fate, transformation and toxicity of Ag⁺ and AgNPs, and further indicate that the acute toxicity of AgNPs should be mainly ascribed to the dissolved Ag⁺ from AgNPs.     

生物柴油吸收VOCs的特性及热力学

采用具有高沸点、低粘度特性的生物柴油作为非极性挥发性有机废气(VOCs)的吸收剂,以甲苯为典型VOCs代表,通过吸收实验考察了生物柴油的甲苯吸收特性.结果发现,在同一浓度下生物柴油吸收甲苯容量优于矿物油,且比水提高1个数量级,并且随着初始浓度升高,吸收容量等比例上升.温度是吸收敏感因素,温度上升会导致吸收容量大幅下降....     

Enhancement of elemental mercury adsorption by silver supported material

Mercury, generally found in natural gas, is extremely hazardous. Although average mercury levels are relatively low, they are further reduced to comply with future mercury regulations, which are stringent in order to avoid releasing to the environment. Herein, vapor mercury adsorption was therefore investigated using two kinds of supports, granular activated carbon (GAC) and titanium dioxide (TiO₂). Both supports were impregnated by silver (5 and 15 wt.%), before testing against a commercial adsorbent (sulfur-impregnated activated carbon, SAC). The adsorption isotherm, kinetics, and its thermodynamics of mercury adsorption were reported. The results revealed that Langmuir isotherm provided a better fit to the experimental data. Pseudo second-order was applicable to describe adsorption kinetics. The higher uniform Ag dispersion was a key factor for the higher mercury uptake. TiO₂ supported silver adsorbent showed higher mercury adsorption than the commercial one by approximately 2 times. Chemisorption of mercury onto silver active sites was confirmed by an amalgam formation found in the spent adsorbents.     

芦苇和香蒲对重金属钼的吸收特性研究

研究了水生植物芦苇和香蒲对重金属钼的吸收特性.通过短期室内水培实验,对比考察了2种植物对重金属钼的耐毒性、动态去除率、吸收过程及富集情况,并对在不同浓度营养液中植物对重金属钼吸收的影响进行了分析.结果表明,2种植物钼中毒导致其茎叶发黄、蒸腾能力下降,在钼浓度为2～20 mg.L-1时,香蒲对重金属钼的耐毒性较芦苇强.香蒲对重金属钼的去除率高于芦苇,在钼浓度为2 mg.L-1时,香蒲和芦苇去除率分别为87%和62%.2种植物对重金属钼的吸收是一个动态平衡过程,且以被动吸收为主.香蒲对钼的富集量较芦苇高,且植物地上部重金属积累量大于根部,符合超积累植物特征之一.营养液浓度的增加不会提高植物对重金属钼的吸收量,反而会因离子竞争等因素使去除率有所下降.芦苇和香蒲对溶液中钼的吸收均具有显著效果,香蒲吸收效果较芦苇好.     

底泥磷的吸附与释放研究进展

富营养化是当今世界面临的一个严重的环境问题。在大多数情况下，磷是最主要的限制因子，沉积物(底泥)中的磷的循环在一定程度上决定着富营养化的进程，对水体磷含量有深刻的影响，即所谓的内源污染。本文结合国内外研究最新动态，对底泥磷形态、磷释放与水体水质的关系作了概述，重点对影响沉积物(底泥)磷的释放与吸附的因子作了分析，并对底泥磷释放的研究方向发表了一些见解。     

Enhancement of elemental mercury adsorption by silver supported material

Mercury, generally found in natural gas, is extremely hazardous. Although average mercury levels are relatively low, they are further reduced to comply with future mercury regulations, which are stringent in order to avoid releasing to the environment. Herein, vapor mercury adsorption was therefore investigated using two kinds of supports, granular activated carbon (GAC) and titanium dioxide (TiO₂). Both supports were impregnated by silver (5 and 15 wt.%), before testing against a commercial adsorbent (sulfur-impregnated activated carbon, SAC). The adsorption isotherm, kinetics, and its thermodynamics of mercury adsorption were reported. The results revealed that Langmuir isotherm provided a better fit to the experimental data. Pseudo second-order was applicable to describe adsorption kinetics. The higher uniform Ag dispersion was a key factor for the higher mercury uptake. TiO₂ supported silver adsorbent showed higher mercury adsorption than the commercial one by approximately 2 times. Chemisorption of mercury onto silver active sites was confirmed by an amalgam formation found in the spent adsorbents.     

在原子吸收分光光度计上测定汞

利用原子吸收分光光度计上的燃烧头稍改进原子化和气路就可测定汞。该法具有灵敏度高,精密度和准确度均较好,操作简单,基本上自动化等优点。     

叶菜类蔬菜对海藻碘的吸收与积累特征

以叶菜类蔬菜菠菜、大白菜、生菜、香菜、芥菜和雪菜为研究对象,利用海藻固体碘肥和海藻液体碘肥作为外源碘,在露天和大棚栽培条件下进行蔬菜植物碘强化的田间试验,通过分析蔬菜对碘吸收量的动态变化和碘在蔬菜各器官的分布和分配状况,研究了叶菜类蔬菜对外源碘的吸收与积累特征.结果表明,供试叶菜可食部分中碘的含量随着外源碘添加量的增加而增加;随着取样时间的延后,叶菜可食部分中碘的含量呈现出下降的趋势;喷施液体碘肥比土施固体碘肥更有利于叶菜对碘的吸收和积累,前者使吸收的碘大部分积累在叶面,后者则大部分积累在根部.     

己内酰胺-四丁基溴化铵类离子液体吸收SO2效率的研究

采用己内酰胺-四丁基溴化铵为原料,按摩尔配比为2∶1配制成[CPL][TBAB]类离子液体,制备的离子液体与乙醇溶液按体积比为1.5∶1混合以降低其粘度,利用筛板塔进行吸收实验,考察最佳吸收条件及最大吸收效率。结果表明,在实验条件下,最大的吸收效率条件为:离子液体的流量为60 L/h,SO2的流量为0.2 L/min,SO2为30℃,最大吸收效率为47.6%。     

吸附法处理焦化废水的研究进展

焦化废水是煤制焦炭、煤气净化及焦化产品回收过程中产生的废水,其成分复杂多变,属于难处理的工业废水。介绍了近年来焦化废水的吸附处理技术,包括常用吸附剂及吸附法与其它方法联用的应用情况。     

多孔介质内H2S贫氧燃烧制氢数值模拟

为探索H2S在多孔介质内超绝热缺氧燃烧裂解制氢的机理,采用流体力学数值模拟与化学动力学研究相结合的方法,使用一个17组分、57步的复杂化学反应机理,模拟了H2S在直径为3 mm的Al2O3圆球堆积的多孔燃烧反应器内的缺氧燃烧制氢过程,模拟结果与试验数据基本吻合.模拟结果显示:富燃条件下,多孔介质内H2S的燃烧温度超过了绝热燃烧温度,为H2S的裂解制硫、制氢提供了高温环境,H2S部分裂解生成单质硫和氢气,从而实现了对硫化氢中的硫和氢同时利用的目的.     

Resistance and biosorption mechanism of silver ions by Bacillus cereus biomass

Biosorption of silver ions onto Bacillus cereus biomass was investigated. Overall kinetic experiments were performed for the determination of the necessary contact time for the attainment of equilibrium. It was found that the overall biosorption process was best described by pseudo second-order kinetic model. The crystals detected by scanning electron microscope and X-ray photoelectron spectroscopy suggested the precipitation was a possible mechanism of biosorption. The molecular genetics of silver resistance of B. cereus biomass was also detected and illustrated by a whole cell sensor tool.     

针铁矿催化过氧化氢降解PCB28

以针铁矿（α-FeOOH）为催化剂,在针铁矿与H2O2组成的非均相Fenton体系内对PCB28的降解进行了研究,讨论了针铁矿、H2O2浓度和体系pH对PCB28降解率的影响,并初步揭示了PCB28的降解机理.结果表明,PCB28在非均相Fenton体系中能发生明显的降解作用.PCB28的降解率随H2O2和针铁矿初始浓...     

花生壳活性炭对六价铬的吸附

研究了以花生壳为原料,采用氯化锌活化法制取活性炭的最佳工艺条件,通过单因素实验得出制备花生壳活性炭的最佳条件是:活化温度为500℃,活化时间为1h,花生壳与氯化锌溶液的料液比为1∶ 2,氯化锌溶液质量浓度为30%.通过正交实验得出了花生壳活性炭吸附处理六价铬的最佳工艺条件是:吸附温度45℃,吸附时间60min,振荡速率190r/min,活性炭用量为2g/L.对花生壳活性炭的再生以及与市售活性炭吸附性能的对比进行了一定的探讨.     

河流泥沙吸附石油的实验研究

研究河流中的泥沙对石油的吸附和解吸规律对建立水质数学模型及水质预测预报具有重要意义，可为水域石油污染的治理提供依据。本文根据静态实验研究成果，建立了通用的吸附反应方程，在水槽中进行了均匀输沙吸附实验，并用解析解进行计算与动态实验结果进行比较，其结果较为理想。最后对河流底沙的吸附进行了初步探讨，分析了石油向底沙层扩散的过程。     

膨润土吸附剂对水中酚吸附性能研究

讨了用羟基铝、硫酸处理过的膨润土对水中酚的吸附性能．试验结果表明：酚径膨润土吸附剂吸附后，其去除率为７３．８８％，处理水再经活性炭吸附，酚去除率可达９９．８％、降至０．５ｍｇ／Ｌ以下．     

粘土吸附水中氟离子的研究

研究了粘土和明矾去除饮用水中氟离子的机理,探讨了pH值、溶液温度、氟离子浓度和吸附时间对粘土吸附饮用水中氟离子的影响.结果表明,粘土对饮用水中氟离子具有较好的吸附效果,是较为理想的饮水除氟材料.     

吸收法处理玉米深加工过程异味气体的实验研究

为解决玉米深加工过程中产生的异味气体造成的环境污染问题,采用吸收法对玉米深加工的废气中VOCs进行了处理实验,分别测定了不同吸收剂(清水、3%碱液、1.25%硫酸、森林之源除臭剂、烷基苯磺酸钠溶液、非离子型相转移试剂X溶液)对VOCs的去除效果,并和生物洗涤法进行比较分析,其中,0.03%非离子型相转移试剂溶液对玉米深加工废气中VOCs可以达到95%以上的去除效果,吸收液可送废水处理设施处理。