水滑石与磷酸银可见光催化剂的活性对比研究

本文合成了具备水滑石结构(LDH)的Zn-Cr LDH、Zn-Ti LDH以及Ag3PO43种半导体光催化剂,并对它们的催化性能进行对比研究。XRD和SEM分析表明,Zn-Cr LDH、Zn-Ti LDH具有层状结构而Ag3PO4呈纳米球状结构。UV-Vis分析表明,Ag3PO4和Zn-Cr LDH能够吸收可见光(>420 nm)。在可见光照射与添加AgNO3作为电子受体的条件下,Zn-TiLDH几乎没有光催化活性,而Ag3PO4的光催化活性高于Zn-Cr LDH。Ag3PO4在光解水实验中180 min内氧气产量约1.2mL,而Zn-Cr LDH约为0.65 mL。光催化降解有机污染物实验中,在Ag3PO4催化作用下,120 min内亚甲基蓝(MB)被完全降解,在240 min内46%的对硝基酚(PNP)被降解,而Zn-Cr LDH相应的去除率分别为61%和27%。     

电解锰渣中锰的浸出条件及特征

采用水洗-酸解法回收电解锰渣中锰,探讨了清水量、酸量以及温度在不同阶段对锰浸(洗)出条件的影响,分析了回收锰的主要因素及浸出特征。实验结果表明,50 g电解锰渣经m渣∶m水=1∶10的清水水洗后,采用10%的硫酸在70℃的水浴温度下酸解2 h,Mn2+浸出量为1.673 g,回收率达到97.3%,而温度和酸度对锰离子的浸出影响明显,酸度调控可有效分离酸浸锰液中金属成分,为减少电解锰渣环境污染的同时,实现电解锰渣资源化利用。     

不同改性多壁碳纳米管对Cr3+的吸附性能

通过催化裂解法制备多壁碳纳米管,利用不同化学试剂对多壁碳纳米管改性,研究了不同化学改性对多壁碳纳米管表面物理化学特性的影响和Cr3＋的吸附特性。结果表明,所制备的多壁碳纳米管孔隙均匀,外径为30～50 nm,长度为0.5～2μm,经过不同化学改性表面有效地引入了含氧基团。未改性、H2SO4、HNO3、H2SO4-HNO3改性碳纳米管对Cr3＋的吸附动力学均符合Langergren模型;吸附等温线均符合Freundlich模型。温度和pH升高均有利于改性多壁碳纳米管对Cr3＋的吸附。     

MnxCe1-xO2／γ-Al2O3催化剂的制备及其催化甲苯的燃烧性能

以γ-Al2O3为载体,以MnxCe1-xO2为催化活性组分,采用浸渍法制备了一系列负载型MnxCe1-xO2／γ-Al2O3催化剂（x=0、0．2、0．4、0．6、0．8、0．9、1）,在固定床反应器中评价了催化剂对甲苯的催化燃烧性能。结果表明,MnxCe1-xO2／γ-Al2O3催化剂的催化活性与催化剂的焙烧温度、活性组分MnxCe1-xO2的负载量以及Mn、Ce摩尔比有显著关系,其中焙烧温度550℃、负载量为20％、Mn、Ce摩尔比为4：1时,即MnxCe1-xO2／γ-Al2O3催化剂对甲苯的催化性能最佳,反应温度为180℃时,甲苯的转化率达到95％。并在连续100h的稳定性操作后,催化剂的活性基本无变化。采用XRD、BET以及SEM等分析测试手段对催化剂的结构以及表面进行了表征。     

浅谈我国旧衣服回收及再利用

随着人们生活水平的提高,服装更新速度越来越快,废旧衣服既污染环境,其再利用价值也没有发挥出来.把循环经济中的“3R原则”应用到废旧衣服回收中,以发挥废旧衣服的最大价值.     

Fe3O4/Ag磁性纳米颗粒去除水中的铅离子

采用水相共沉淀法制备小尺寸磁性Fe₃O₄纳米颗粒,以没食子酸作为还原剂和表面修饰剂,还原Ag[(NH₃)₂]⁺制备出Fe₃O₄/Ag磁性纳米颗粒。研究该磁性纳米颗粒对水溶液中铅离子的吸附行为,研究结果表明,pH为7.0,吸附温度30℃时可得到最好的处理效果,铅的去除率可达99.7%以上,Fe₃O₄/Ag颗粒吸附行为符合二级动力学模型(R² > 0.99)。该磁性纳米颗粒经过多次再生处理后,仍具有很好的吸附效果,表明Fe₃O₄/Ag在水处理方面拥有良好的应用前景。     

钙对李氏禾富集和耐受铬的调控作用

通过水培实验,研究钙对铬胁迫下李氏禾幼苗生理生化、草酸分泌及铬吸收量的影响,考察钙对李氏禾体内草酸合成的调控,进而促进李氏禾的铬耐性富集能力的作用。结果显示,不同浓度Cr³⁺胁迫下缺钙处理,李氏禾生长受抑制及质膜过氧化作用加剧,体内总草酸含量为对照处理的113%~169%,且主要表现为水溶性草酸含量显著高于对照,水溶性草酸含量为对照处理的135%~197%;高钙处理,李氏禾细胞膜透性、丙二醛（MDA）含量低于对照,李氏禾叶部总草酸含量为对照处理的125%~155%,且主要表现为不溶性草酸含量显著高于对照,其含量为对照处理的181%~270%。低浓度（0.2、0.4 mmol/L）铬胁迫下,高钙处理总铬含量分别为对照处理的175%和215%,高浓度（0.8、1.0 mmol/L）铬胁迫下,总铬含量与对照处理无显著差异（P>0.05）。可见,添加Ca²⁺能在一定Cr³⁺浓度胁迫下,有效缓解铬对李氏禾的毒害,且能通过提高植物体内不溶性草酸含量达到促进植物富集和耐受铬的能力。     

Induction of hepatic drug metabolizing enzymes in mammals by pesticides: A review

Abstract

The induction of drug metabolizing enzymes in mammals is summarized including both enzymes of the cytochrome P‐450‐dependent microsomal mixed function oxidase system and glutathione S‐transferases. Particular emphasis is placed on the role of pesticides as inducers, the early work being summarized while investigations carried out at North Carolina State University are considered in greater detail. Finally, the possible significance of induction is considered.     

Effects of Soil Amendments at a Heavy Loading Rate Associated with Cover Crops as Green Manures on the Leaching of Nutrients and Heavy Metals from a Calcareous Soil

The potential risk of groundwater contamination by the excessive leaching of N, P and heavy metals from soils amended at heavy loading rates of biosolids, coal ash, N‐viro soil (1:1 mixture of coal ash and biosolids), yard waste compost and co‐compost (3:7 mixture of biosolids to yard wastes), and by soil incorporation of green manures of sunn hemp (Crotalaria juncea) and sorghum sudangrass (Sorghum bicolor × S. bicolor var. sudanense) was studied by collecting and analyzing leachates from pots of Krome very gravelly loam soil subjected to these treatments. The control consisted of Krome soil without any amendment. The loading rate was 205 g pot^? 1 for each amendment (equivalent to 50 t ha^? 1 of the dry weight), and the amounts of the cover crops incorporated into the soil in the pot were those that had been grown in it. A subtropical vegetable crop, okra (Abelmoschus esculentus L.), was grown after the soil amendments or cover crops had been incorporated into the soil. The results showed that the concentration of NO₃‐N in leachate from biosolids was significantly higher than in leachate from other treatments. The levels of heavy metals found in the leachates from all amended soils were so low, as to suggest these amendments may be used without risk of leaching dangerous amounts of these toxic elements. Nevertheless the level of heavy metals in leachate from coal ash amended soil was substantially greater than in leachates from the other treatments. The leguminous cover crop, sunn hemp, returned into the soil, increased the leachate NO₃‐N and inorganic P concentration significantly compared with the non‐legume, sorghum sudangrass. The results suggest that at heavy loading rates of soil amendments, leaching of NO₃ ^? could be a significant concern by application of biosolids. Leaching of inorganic P can be increased significantly by both co‐compost and biosolids, but decreased by coal ash and N‐viro soil by virtue of improved adsorption. The leguminous cover crop, sunn hemp, when incorporated into the soil, can cause the concentration of NO₃‐N to increase by about 7 fold, and that of inorganic P by about 23% over the non‐legume. Regarding the metals, biosolids, N‐viro soil and coal ash significantly increased Ca and Mg concentrations in leachates. Copper concentration in leachate was increased by application of biosolids, while Fe concentration in leachates was increased by biosolids, coal ash and co‐compost. The concentrations of Zn, Mo and Co in leachate were increased by application of coal ash. The concentrations of heavy metals in leachates were very low and unlikely to be harmful, although they were increased significantly by coal ash application.     

Metabolism of the Nonylphenol Isomer [Ring-U-14c]-4-(3′,5′-Dimethyl-3′-Heptyl)-Phenol by Cell Suspension Cultures of Agrostemma githago and Soybean

Abstract

The biotransformation of the nonylphenol isomer [ring-U-¹⁴C]-4-(3′,5′-dimethyl-3′-heptyl)-phenol (4-353-NP, consisting of two diastereomers) was studied in soybean and Agrostemma githago cell suspension cultures. With the A. githago cells, a batch two-liquid-phase system (medium/n-hexadecane 200:1, v/v) was used, in order to produce higher concentrations and amounts of 4-353-NP metabolites for their identification; 4-353-NP was applied via the n-hexadecane phase. Initial concentrations of [¹⁴C]-4-353-NP were 1 mg L^?1 (soybean), and 5 and 10 mg L^?1 (A. githago). After 2 (soybean) and 7 days (A. githago) of incubation, the applied 4-353-NP was transformed almost completely by both plant species to four types of products: glycosides of parent 4-353-NP, glycosides of primary 4-353-NP metabolites, nonextractable residues and unknown, possibly polymeric materials detected in the media. The latter two products emerged especially in soybean cultures. Portions of primary metabolites amounted to 19–22% (soybean) and 21–42% of applied ¹⁴C (A. githago). After liberation from their glycosides, the primary 4-353-NP metabolites formed by A. githago were isolated by HPLC and examined by GC-EIMS as trimethylsilyl derivatives. In the chromatograms, eight peaks were detected which due to their mass spectra, could be traced back to 4-353-NP. Seven of the compounds were side-chain monohydroxylated 4-353-NP metabolites, while the remaining was a (side-chain) carboxylic acid derivative. Unequivocal identification of the sites of hydroxylation/oxidation of all transformation products was not possible. The main primary metabolites produced by A. githago were supposed to be four diastereomers of 6′-hydroxy-4-353-NP (about 80% of all products identified). It was concluded that plants contribute to the environmental degradation of the xenoestrogen nonylphenol; the toxicological properties of side-chain hydroxylated nonylphenols remain to be examined.