活性焦和活性炭负载纳米铁处理TNT红水中的二硝基甲苯磺酸钠

以活性焦和活性炭为载体,采用液相还原法制备了负载纳米铁,比较了两种负载纳米铁对TNT红水中难降解物质二硝基甲苯磺酸钠(包括2,4-DNT-3-SO3Na和2,4-DNT-5-SO3Na)的去除能力。实验结果表明,作为负载材料活性焦的相对有效比表面积与孔体积要优于活性炭,而且有利于更好地发挥出负载纳米铁的优势。单位面积活性焦负载纳米铁去除2,4-DNT-5-SO3Na的能力明显高于活性炭负载纳米铁,单位面积活性焦负载纳米铁去除2,4-DNT-3-SO3Na的能力在较小投加量条件下高于活性炭负载纳米铁,但均随投加量的增加而下降;而对于活性炭负载纳米铁,其单位面积去除能力基本不受投加量的影响,而且对二硝基甲苯磺酸钠的去除率高于活性焦负载纳米铁。耦合混凝沉淀的总去除效果表明,单位面活性焦负载纳米铁对2,4-DNT-5-SO3Na的去除能力高于活性炭负载纳米铁,而对2,4-DNT-3-SO3Na的去除能力则低于活性炭负载纳米铁。     

零价铁耦合芬顿氧化法处理TNT红水

采用零价铁耦合芬顿氧化法处理TNT红水,研究了初始pH、零价铁投加量、过氧化氢(H_2O_2)投加量及温度对红水中总有机碳(TOC)去除效果的影响,同时进行了TOC去除过程中反应动力学的探讨。结果表明,零价铁耦合芬顿氧化体系可有效降解TNT红水中的2,4-二硝基甲苯-3-磺酸钠和2,4-二硝基甲苯-5-磺酸钠。在初始pH为2,温度为20?C的条件下,加入1.5 g·L~(-1)零价铁反应1 h后,再加入100 mL·L~(-1)H_2O_2反应4 h,红水中二硝基甲苯磺酸盐浓度从500 mg·L~(-1)降至0 mg·L~(-1),去除率为100%,TOC浓度从150 mg·L~(-1)降至30 mg·L~(-1),去除率达到80%。反应中TOC的降解过程遵循拟二级反应动力学方程。零价铁耦合芬顿氧化法可以作为TNT红水的有效处理途径。     

Fe~0-C微电解去除地下水中2,4-DNT的影响因素

采用批实验研究初始pH值、溶解氧(DO)和地下水中常见的阴、阳离子等因素对Fe~0-C微电解对地下水中2,4-二硝基甲苯(2,4-DNT)去除率的影响,并分析Fe~0-C降解2,4-DNT的产物。结果表明,在pH=7,DO=0.23 mg·L~(-1)的条件下,Fe~0-C去除溶液中2,4-DNT有明显的效果,反应200 min时,去除率达到83.09%,比Fe~0和C的去除率提高了74.56%和9.89%;酸性条件下有利于2,4-DNT去除,初始pH=5的条件下,溶液中2,4-DNT的去除率为82%,而初始pH=10时,2,4-DNT的去除率分别为64%;反应体系中含有较高浓度的溶解氧有利于2,4-DNT的去除,在DO=9.26 mg·L~(-1)条件下,2,4-DNT的去除率比DO=0.23 mg·L~(-1)时提高了9.5%;地下水中一定浓度的阴(Cl-、SO_4~(2-))、阳离子(Ca~(2+)、Mg~(2+)、Na~+、K~+)可以提高2,4-DNT的去除率,提高率小于10%。反应过程中2,4-DNT降解的产物包括2-氨基-4-硝基甲苯(2A4 NT)、4-氨基-2-硝基甲苯(4A2 NT)和2,4-二氨基甲苯(2,4-DAT)。     

羧甲基纤维素改性纳米钯铁双金属去除水中2,4-二氯苯酚的影响因素及机理

利用液相还原法制备了纳米零价铁(nZVI)、纳米钯铁双金属(Pd/Fe)、羧甲基纤维素(CMC)改性nZVI(CMC-Fe)和CMC改性钯铁双金属(CMC-Pd/Fe)4种铁基纳米材料，并用扫描电子显微镜(SEM)和X射线衍射仪(XRD)对其进行了表征。研究了这4种材料对水中2,4-二氯苯酚(2,4-DCP)的表观去除率，考察了铁基纳米材料投加量、Pd负载量、溶液初始pH及污染物浓度等因素对CMC-Pd/Fe去除2,4-DCP的影响，并探讨了可能的作用机理。结果表明，在4种材料中，CMC修饰的CMC-Pd/Fe的分散性最好，粒径明显小于未用CMC修饰的nZVI和Pd/Fe。4种材料对2,4-DCP的表观去除率为CMC-Pd/Fe>CMC-Fe>Pd/Fe>nZVI。随着CMC-Pd/Fe投加量和Pd负载量的增加，CMC-Pd/Fe对2,4-DCP的表观去除率增大，而随着2,4-DCP浓度的升高，CMC-Pd/Fe对2,4-DCP的表观去除率下降。当溶液初始pH=3、5和7时，CMC-Pd/Fe对2,4-DCP的表观去除率分别为94.34%、99.50%和96.62%;...     

铁碳填料预处理硝基苯废水及其抗板结稳定性

为了探究铁碳微电解技术对硝基苯废水预处理的稳定性,基于市售的3种铁碳微电解填料构建硝基苯模拟废水的连续处理装置,结合材料表征结果探究了铁碳微电解填料的板结机制,并提出了抗板结功能的结构特征。结果表明：1号、3号填料为烧结型填料,2号填料为免烧型填料。3种铁碳填料对硝基苯的去除率为20%～40%,其中2号填料具有最高的去除率和最好的稳定性。1号和3号填料在长时间运行过程中产生大量堆积的含铁化合物,影响铁碳微电解的反应界面,从而导致硝基苯的去除率降低。填料抗板结的构型主要受到非铁碳组分骨架的影响,防止剥落的铁碳颗粒堵塞铁碳填料的反应界面,同时铁碳元素空间分布均匀,可为抗板结铁碳填料的制备提供参考。     

铁碳微电解填料制备及其对亚甲基蓝的降解

针对传统铁碳微电解工艺中填料易板结的问题,在较低的烧结温度800℃条件下,将铁、活性炭、粘结剂和催化剂按一定配料比混合烧结4 h制备了一种铁碳微电解填料。将印染废水中的染料成分亚甲基蓝作为目标污染物,探究溶液pH、铁碳材料添加量和亚甲基蓝起始浓度等反应条件对亚甲基蓝降解效率的影响。在pH=3,铁碳投加量30 g·L~(-1),亚甲基蓝浓度10 mg·L~(-1)的条件下,亚甲基蓝的去除率达到55%左右;相同条件下对于微电解填料的循环使用实验中亚甲基蓝的去除率能维持在50%以上,证明了该微电解填料具有连续运行的能力。另外,通过微电解与芬顿反应联用的初步实验发现联用效果对于亚甲基蓝的降解率能大幅度提升至90%以上,证明微电解与芬顿反应联用具有较大的应用潜力。     

铁碳微电解/H_2O_2耦合类Fenton法预处理高浓度焦化废水

采用铁碳微电解/H_2O_2耦合类Fenton法预处理高浓度焦化废水,通过正交和单因素实验研究了废水初始pH、不同质量的微电解填料、H_2O_2投加量及反应时间对COD处理效果的影响,同时研究了COD降解动力学。结果表明:最佳控制条件是废水初始pH为3、铁碳填料投加量为300 g/L、H_2O_2投加量为80 m L/L、反应时间为160 min,此时COD的去除率达到87%以上;H_2O_2的加入可使铁碳微电解/H_2O_2系统COD的去除率提高37.34%,铁碳微电解/H_2O_2系统COD反应动力学方程为y=0.5296x-0.6218,相关系数R~2为0.9917。     

铁炭微电解深度处理焦化废水的研究

采用曝气铁炭微电解工艺对焦化废水进行了深度处理.结果表明,在活性炭、铁屑和NaCl投加量分别为10 g/L、30 g/L和200 mg/L的条件下反应240 min,出水COD去除率在30%～40%;酸性条件可以进一步提高COD去除率;微电解可以去除原生化出水中的难降解有机物,出水物质的分子量主要集中于2000 Da以下,以脂类和烃类化合物为主;出水的可生化性有了大幅度提高,BOD5/COD由0.08增加到0.53.实验结果表明,铁炭微电解是深度处理焦化废水的一种有效工艺.     

微纳米气泡协同铁碳微电解工艺处理盐酸四环素废水

采用微纳米气泡联合铁碳微电解法处理盐酸四环素废水,用XRD和FT-IR对铁碳材料反应前后的结构进行了表征,研究了不同反应时间、铁碳投加量、pH、微纳米气泡进气量对盐酸四环素去除率的影响和一级反应动力学的特征。结果表明:微纳米气泡对铁碳微电解有显著的协同作用;当反应时间为120 min、铁碳投加量为100 g·L-1、pH=3、微纳米气泡进气量为30 mL·min-1时,浓度为20 mg·L-1的盐酸四环素降解效果达到最佳,降解率为80.84%,TOC去除率为47.89%。通过LC-MS测定分析,盐酸四环素经过分解转化为m/z=194、m/z=181和m/z=174的产物,并最终转化分解为CO2和H2O。以上研究结果可为抗生素废水处理提供有益的参考。     

大孔树脂对还原后TNT红水中苯胺类物质的吸附性能

采用零价铁对2,4,6-三硝基甲苯(TNT)红水进行预处理,可将硝基物还原为对应苯胺类化合物,从而降低其毒性,提高可生化性,并使其带电荷,易于后续资源化利用。为了使还原后的TNT红水中的苯胺类物质与无机盐进行分离,研究了大孔吸附树脂HYA-106对还原后TNT红水中苯胺类物质的吸附行为。条件优化实验表明,在温度为293 K,p H为3.0,树脂用量为140 g·L~(-1)时,COD和苯胺类去除率分别为91.4%和94.7%。吸附等温线表明,吸附量与温度呈负相关,吸附更符合Freundlich吸附模型,不同温度下相关系数均大于0.97。热力学研究表明,该吸附过程是焓推动的自发过程,范德华力、疏水效应、偶极力和氢键是主要的吸附作用力。动力学实验表明该吸附符合准二级动力学速率方程,吸附在150min基本达到平衡,内扩散为控速步骤。     

Water quality parameters controlling the photodegradation of two herbicides in surface waters of the Columbia Basin,Washington

The water quality parameters nitrate-nitrogen, dissolved organic carbon, and suspended solids were correlated with photodegradation rates of the herbicides atrazine and 2,4-D in samples collected from four sites in the Columbia River Basin, Washington, USA. Surface water samples were collected in May, July, and October 2010 and analyzed for the water quality parameters. Photolysis rates for the two herbicides in the surface water samples were then evaluated under a xenon arc lamp. Photolysis rates of atrazine and 2,4-D were similar with rate constants averaging 0.025 h⁻¹ for atrazine and 0.039 h⁻¹ for 2,4-D. Based on multiple regression analysis, nitrate-nitrogen was the primary predictor of photolysis for both atrazine and 2,4-D, with dissolved organic carbon also a predictor for some sites. However, at sites where suspended solids concentrations were elevated, photolysis rates of the two herbicides were controlled by the suspended solids concentration. The results of this research provide a basis for evaluating and predicting herbicide photolysis rates in shallow surface waters.     

复合功能吸附树脂对双组分萘系化合物的竞争吸附研究

1-氨基 -2 -萘酚 -4 -磺酸 ( 1,2 ,4-酸 )和 2 -萘酚自不同双组分吸附体系中吸附至复合功能吸附树脂 AL -1上的吸附等温线符合 F reundlich等温模型。1,2 ,4-酸的吸附为吸热过程 ,而 2 -萘酚的吸附为放热过程。固相上的 2 -萘酚几乎不影响 1,2 ,4-酸的吸附 ,而固相上的 1,2 ,4-酸大大削弱了 2 -萘酚的吸附。两种溶质在吸附位点上的竞争为主要作用机制。     

Effects of alternative electron donors,acceptors, and inhibitors on 2,4‐dichlorophenoxyacetic acid and 2,4,5‐trichlorophenoxyacetic acid dechlorination in soil

Abstract

The potential for dechlorinating 2,4‐dichlorophenoxyacetic acid (2,4‐D) and 2,4,5‐trichlorophenoxyacetic acid (2,4,5‐T) in soil with a consortium showing stable dechlorinating activity was investigated. The effects of adding electron donors and/or acceptors under three anaerobic reducing conditions was compared. Results show that both 2,4‐D and 2,4,5‐T dechlorination rates were enhanced in methanogenic conditions, delayed in sulfate‐reducing conditions, and inhibited in denitrifying conditions. Also under the same three conditions dechlorination was be enhanced by the addition of lactate, pyruvate, and acetate, delayed by the addition of manganese oxide and vitamin B₁₂, and inhibited by the addition of ferric chloride. Response to treatment with such microbial inhibitors as bromoethane sulfonic acid (BESA), vancomycin, and molybdate suggests that the major bacteria involved in 2,4‐D and 2,4,5‐T dechlonnation is methanogen followed joined by sulfate‐reducing bacteria and eubacteria.     

Fe-MCM-41催化氧化2,4-二氯苯氧乙酸

采用水热法合成了Fe-MCM-41中孔分子筛,紫外、红外及XRD表征显示铁离子已进入中孔分子筛骨架。以H2O2为氧化剂形成类Fenton试剂,实验结果表明,在催化剂加入量为1 g/L、H2O2体积分数为6%、pH为4、反应时间为10h、反应温度为35℃的条件下,处理质量浓度为50 mg/L的2,4-D废水的降解率达94.95%。宏观动力学研究显示,该反应近似为一级反应,反应速率常数、表观活化能分别为0.21667 min-1和26.65 kJ/mol。     

Effects of 2,4-dichlorophenoxyacetic acid formulation on medulla spinalis of Poecilia reticulata: A histopathological study

This study investigated the possible effects of a commonly used foliar herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) formulation on medulla spinalis of lebistes. Fish were exposed to 2,4-D (15, 30, 45 mg L⁻¹), behavioral changes were monitored. Fish were fixed, histopathological examination was carried out on sections taken from the upper parts of the fish body. Histopathology showed increase in neuronal loss, swelling indicating formation of intracellular edema, vacuolization noticed as the formation of vacuoles within or adjacent to cells, deformation in the Nissl granules, pyknosis and gliosis in medulla spinalis. Behavioral changes were decreased general activity, grouping, shortness in breath, sudden rotations and jumping, loss of equilibrium and colour. In conclusion, this commercial formulation of 2,4-D is considerably neurotoxic to lebistes. Fish constitute the last link in the chain of the feeding cycle in aquatic eco-system, number of studies investigating acute and chronic neurotoxicity of various herbicides in fish should be increased.     

2,4-Dichlorophenoxy Acetic Acid Mineralization in Amended Soil

The application of municipal biosolid or liquid hog manure to agricultural soils under laboratory conditions at 20°C influenced the fate of the herbicide 2,4-D [2,4-(dichlorophenoxy)acetic acid] in soil. When 2,4-D was added to soil at agronomic rates immediately after the addition of manure or biosolids to a coarse-textured soil, the percentage of 2,4-D mineralized at 100 days was about 47% for both treatments, compared to only 31% for control soils without amendments. The enhanced 2,4-D mineralization as a result of amendment addition was due to an increased heterotrophic microbial activity, with the greatest increases in soil respiration occurring for soils amended with biosolids. When additions of 2,4-D were delayed for one, two, or four weeks after the amendments were applied, the additions of amendments generally reduced 2,4-D mineralization in soil, particularly for manure, indicating that the effect of amendments on enhancing soil microbial activities diminished over time. In contrast, the mineralization of 2,4-D in control soils was less dependent on when 2,4-D was applied in relation to pre-incubations of soil for zero, one, two, or four weeks. The effect of manure on decreasing 2,4-D mineralization in specific soils was as large as the effect of soil texture on differences in 2,4-D mineralization across soils. Because manure was not found to impact 2,4-D sorption by soil, it is possible that 2,4-D mineralization decreased because 2,4-D transformation products were strongly sorbed onto organic carbon constituents in manure-amended soils and were therefore less accessible to microorganisms. Alternatively, microorganisms were less likely to metabolize the herbicide because they preferentially consumed the type of organic carbon in manure that is a weak sorbent for 2,4-D.     

V2O5-TiO2-AlF3/Al2O3催化臭氧化2,4-滴丙酸的氧化效能

为了提高有机物的臭氧化降解效率,工作中利用浸渍法制备了一种新型的三组分催化剂(记为V2O5-TiO2-AlF3/Al2O3)。催化臭氧化降解2,4-滴丙酸的实验结果表明,该催化剂能有效提高臭氧化的效率,体系可能遵循羟基自由基的作用机理。利用相对法计算结果表明,与单独臭氧化相比,V2O5-TiO2-AlF3/Al2O3催化臭氧化体系具有更大的Rct值。重复实验结果表明,该催化剂具有相对较好的稳定性。以上研究结果对推广催化臭氧化技术在实际废水处理中的应用具有重要的实际意义。     

Effects of nozzle types and 2,4-D formulations on spray deposition

The objective of this study was to evaluate the effects of nozzle types and 2,4-D formulations on spray deposition on different targets. Two field experiments were carried out in a completely randomized design, and treatments were arranged in a factorial scheme. Species in experiment 1 were Sumatran fleabane (Conyza sumatrensis) and Brazil pusley (Richardia brasiliensis) and in experiment 2 were soybeans (Glycine max) and Benghal dayflower (Commelina benghalensis). For both experiments, the first factor corresponded to spray nozzles with different settings (AD 110.015 – 61 and 105 L ha^?1; AD 015-D – 75 and 146 L ha^?1; XR 110.0202 – 200 L ha^?1; and ADIA-D 110.02 – 208 L ha^?1) and the second factor consisted of two formulations of 2,4-D (amine and choline). The formulation of 2,4-D choline has contained Colex-D? Technology. Similar or higher spray deposition was observed on the leaves and artificial targets when using 2,4-D choline as compared to the 2,4-D amine formulation, and these differences in deposition were more evident for nozzles applying lower spray volumes. Deposition was more affected by nozzle type when amine formulation was used, compared to choline formulation.     

气相色谱法测定水中的2，4-二硝基氯苯

采用苯萃取,HP-624 30 m×0.53 mm×3.00 μm大口径毛细管柱分离,电子捕获检测器(ECD)检测2,4-二硝基氯苯,得到了良好的分离效果、较宽的线性关系和较高的灵敏度.     

Residues of 2,4‐D in air samples from Saskatchewan: 1966–1975

Abstract

Residues of 2,4‐D (2,4‐dichlorophenoxyacetic acid) in air samples from several sampling sites in central and southern Saskatchewan during the spraying seasons in the 1966–68 and 1970–75 periods were determined by gas‐liquid Chromatographic techniques. Initially, individual esters of 2,4‐D were characterized by retention times and confirmed further by co‐injection and dual column procedures. Since 1973, however, only total 2,4‐D acid levels in air samples have been determined after esterification to the methyl ester and confirmed by gc/ms techniques whenever possible.

Up to 50% of the daily samples collected during the spraying season at any of the locations and during any given year contained 2,4‐D, with butyl esters being found most frequently. The daily 24‐hr mean atmospheric concentrations of 2,4‐D ranged from 0.01 to 1.22 μg/m³, 0.01 to 13.50 μg/m³, and 0.05 to 0.59 μg/m for the iso‐propyl, mixed butyl and iso‐octyl esters, respectively. Even when the samples were analysed for the total 2,4‐D content, i.e. from 1973 onwards, the maximum level of the total acid reached only 23.14 μg/m. In any given year and at any of the sampling sites, about 30% of the samples contained less than 0.01 μg/m³ of 2,4‐D. In another 40% of the samples, the levels of 2,4‐D ranged from 0.01 to 0.099 yg/m. Only about 30% of the samples contained 2,4‐D concentrations higher than 0.1 μg/m³, with only 10% or less exceeding 1 μg/m³.

None of the samples, obtained with the high volume particu‐late sampler, showed any detectable levels of 2,4‐D, indicating little or no transport of 2,4‐D adsorbed on dust particles or as crystals of amine salts.