ATR-FTIR and XPS study on the structure of complexes formed upon the adsorption of simple organic acids on aluminum hydroxide

Information on the binding of organic ligands to metal （hydr）oxide surfaces is useful for understanding the adsorption behaviour of natural organic matter on metal （hydr）oxide. In this study, benzoate and salicylate were employed as the model organic ligands and aluminum hydroxide as the metal hydroxide. The attenuated total reflectance Fourier transform infrared （ATR-FTIR） spectra revealed that the ligands benzoate and salicylate do coordinate directly with the surface of hydrous aluminum hydroxide, thereby forming innersphere surface complexes. It is concluded that when the initial pH is acidic or neutral, monodentate and bridging complexes are to be formed between benzoate and aluminum hydroxide while bridging complexes predominate when the initial pH is alkalic. Monodentate and bridging complexes can be formed at pH 5 while precipitate and bridging complexes are formed at pH 7 when salicylate anions are adsorbed on aluminum hydroxide. The X-ray photoelectron （XP） spectra demonstrated the variation of C 1 s binding energy in the salicyate and phenolic groups before and after adsorption. It implied that the benzoate ligands are adsorbed through the complexation between carboxylate moieties and the aluminum hydroxide surface, while both carboxylate group and phenolic group are involved in the complexation reaction when salicylate is adsorbed onto aluminum hydroxide. The information offered by the XPS confirmed the findings obtained with ATR-FTIR.     

Preliminary Studies on Converting Agricultural Waste into Biodegradable Plastics – Part III: Sawdust

Summary Hardwood sawdust was derivatized either by carboxymethylation, glutaration, maleiation, phthallation, or succination in order to produce anionic materials suitable for complexation with soy protein isolate. Blending each derivative with soy protein isolate resulted in instant precipitation of gels. Infrared spectroscopy and differential scanning calorimetry suggested that each derivative formed a complex with protein. Reaction products could be dried into pellets exhibiting tensile strengths between 0.9–2.4 MPa, suggested that these materials could be promising candidates for biodegradable structural materials.     

A collaborative strategy for enhanced reduction of Cr(VI) by Fe(0) in the presence of oxalate under sunlight: Performance and mechanism

Nanometer-size zero-valent iron (NZVI) is an efficient reducing agent, but its surface is easily passivated with an oxide layer, leading to reaction inefficiency. In our study, oxalate (OA) was introduced into this heterogeneous system of NZVI, which could form ferrioxalate complexes with the NZVI surface-bound Fe³⁺ and dissolved Fe³⁺ in the solution. Photolysis of ferrioxalate complexes can facilitate the generation of Fe²⁺ from Fe³⁺ and CO₂^?- radical, both species have strong reduction capacity. Hence, a “photo-oxalate-Fe(0)” system through sunlight induction was established, which not only prohibited the formation of a surface passivation layer, but also displayed a synergetic mechanism of ferrioxalate photolysis to enhance reduction, exhibiting remarkably higher degradation activity (several times faster) toward the model pollutant Cr(VI) than the mechanism with NZVI alone. Factor tests suggested that both NZVI dosage and OA content markedly affected the reduction rate. Low pH was beneficial to the reduction efficiency. Moreover, recyclability experiment showed that the reduction rate decreased from 0.21706 to 0.03977 min^?1 after three cycles of reuse due to the NZVI losing reaction activity generally, but the system still maintained considerable reduction capacity. Finally, a mechanism was revealed whereby NZVI would transform to Fe oxides after the exhaustion of its reductive power, and the photolysis of ferrioxalate to promote the cycling of iron species played the predominant role in providing extra reduction ability. These features confirm that introduction of OA into Cr(VI) reduction by NZVI through sunlight induction is advantageous and promising.     

强化UV/Fenton法降解水中苯酚的研究

研究了UV/Fenton法处理含苯酚废水时H2 O2 和FeSO4 加入量及苯酚初始浓度对酚去除效果的影响及C2 O2 -4 对UV/Fenton法的增强效果。 [H2 O2 ]=2 0mmol/L ,[FeSO4 ]=5mmol/L ,反应 2 0min ,苯酚初始浓度为 5 0mg/L时 ,酚去除率达 99%。UV/Fenton体系中引入C2 O2 -4 后可有效提高对紫外和可见光的利用率 ,进而提高了对高浓度苯酚废水去除效果     

Effects of grassland degradation on chestnut soil properties in Bashang Plateau, China

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UV/H2O2/草酸铁络合物光降解水中氯仿的研究

以４００Ｗ高压汞灯为紫外光源，Ｈ２Ｏ２－草酸铁络合物为光氧化剂，对氯仿水溶液进行了光降解反应实验研究．结果表明，ＵＶ／Ｈ２Ｏ２草酸铁络合物体系能有效地使水溶液中氧仿迅速光解脱氯；在等摩尔系列溶液中,Ｆｅ３＋／草酸根的摩尔比为１：３时，氯仿光解效果最好：溶液ｐＨ值对氯仿光解有显著影响，ｐＨ值在３－４时光解速率最快；随着Ｈ２ｏ２浓度的增加，氯仿大解速率提高，但Ｈ２Ｏ２浓度较大时，Ｈ２Ｏ２的有效利用率降低；温度对氯仿光解反应有一定影响，反应的表观活化能为７．６ｋＪ／ｍｏｌ.     

高效液相色谱法在无机分析中的应用

本文综述了高效液相色谱法在无机分析中的应用进展。分别介绍了正相、反相、离子对、离子交换、排阻和胶束流动相等液相色谱法在有机金属化合物、金属络合物、无机阳离子和阴离子分离及测定上的实际应用。     

雌二醇在铁(Ⅲ)-草酸盐配合物体系中的光降解

以125W高压汞灯为光源,研究了水中雌二醇(E2)在铁(Ⅲ)-草酸盐体系中的光降解;考查了初始pH值、铁(Ⅲ)/草酸盐配比、E2初始浓度对E2光降解的影响.结果表明,铁(Ⅲ)/草酸盐体系能引发E2光降解.在pH=3·50,Fe(Ⅲ)/草酸盐配比为10·0/120·0μmol·l-1时,2mg·l-1E2光照160min可降解48·0%.在pH3·0—6·0范围内,pH值为3·0—4·0时E2降解率较高;在2·0—10·0mg·l-1范围内,光降解效率随水溶液中E2初始浓度的增加而降低.     

过氧化氢/草酸铁体系太阳光催化降解染料废水的研究

以过氧化氢 /草酸铁络合物作光氧化剂 ,利用太阳光对 10种水溶性染料模拟废水进行了光氧化降解试验研究 ,发现在日光照射下 ,过氧化氢 /草酸铁络合物能使染料溶液迅速降解。以活性艳蓝KN R为代表 ,研究各种因素对光降解的影响。结果表明 ,溶液pH为 2 0～ 4 0时 ,光降解速率快 ;溶液中Fe3 + 与草酸根的摩尔比为 1∶3时 ,光解效果最好 ;提高H2 O2 浓度可以提高光降解速率 ,但H2 O2 的利用率会降低。     

UV/草酸铁/H2O2法处理乙草胺废水的研究

对UV/草酸铁/H2O2法处理乙草胺废水进行研究,考察了H2O2浓度、FeSO4浓度、K2C2O4浓度、pH值及反应时间对乙草胺去除效果的影响.结果表明,当H2O2/FeSO4/K2C2O4(化学剂量数比)=5051,H2O2/乙草胺初始COD(质量浓度比)=31时,该技术对乙草胺的去除率可达85%以上.这表明,采用UV/草酸铁/H2O2法可以有效地处理含乙草胺废水.