木质纤维素酸水解液的脱毒方法研究

由于木质纤维素的酸水解条件剧烈,水解液中必定存在影响微生物生长和发酵的物质,特别是多酚类化合物,需对水解液进行脱毒处理。通过探讨8种脱毒方法对还原糖损失率和酚类脱出率的影响,研究发现,树脂XDA-1+CaCO3,脱除酚类效果最好,还原糖损失率较低,并通过生物性检验也表现了良好的效果。     

Phenolic Antioxidants in Some Vigna Species of Legumes and their Distinct Inhibitory Effects on α-Glucosidase and Pancreatic Lipase Activities

Phenolic extracts of 4 Vigna species of legumes (mung bean, moth bean, and black and red varieties of adzuki beans) were evaluated for phenolic contents, antioxidant activities, and inhibitory properties against α-glucosidase and pancreatic lipase. Results showed that adzuki bean varieties contain higher phenolic indexes than mung bean and moth beans. Adzuki bean (black) variety was found to be the most active 2,2′-diphenyl-1-picrylhydrazyl and superoxide anion scavenger. However, the hydrogen peroxide scavenging and metal chelating abilities were significantly higher in adzuki bean (red) variety. Mung bean exhibited least antioxidant activities in all the methods tested. Phenolic extracts from these legumes also showed distinct variations in the inhibition of enzymes associated with hyperglycemia and hyperlipidemia. Inhibitory activities of all the extracts against lipase were found to be more potent than α-glucosidase. Although, α-glucosidase inhibitory activity was superior in the black variety of adzuki bean (IC(50,) 26.28 mg/mL), both adzuki bean varieties (black and red) along with moth bean showed strong inhibitory activities on lipase with no significant difference in their IC(50) values (7.32 to 9.85 mg/mL). These results suggest that Vigna species of legumes are potential source of antioxidant phenolics and also great sources of strong natural inhibitors for α-glucosidase and lipase activities. This information may help for effective utilization of these legumes as functional food ingredients for promoting health. Practical Application: Vigna species of legumes are good sources of phenolic antioxidants and strong natural inhibitors of enzymes associated with diabetes and obesity. Therefore, utilization of these legumes in the development of functional foods with increased therapeutic value would be a significant step toward health promotion and wellness.     

不同干酪乳杆菌菌株对α-葡萄糖苷酶抑制作用的比较

从14株干酪乳杆菌中筛选出11株具有凝乳作用的菌株,采用以麦芽糖酶为靶向酶的α-葡萄糖苷酶抑制剂体外筛选模型,分析了不同干酪乳杆菌发酵脱脂乳上清对α-葡萄糖苷酶的抑制作用。结果表明,不同菌株发酵脱脂乳上清对麦芽糖酶的抑制活性具有明显的菌株特异性,且随着发酵时间延长,α-葡萄糖苷酶抑制活性呈现上升趋势。其中,干酪乳杆菌LC2W在37℃发酵10%(w/w)脱脂乳96 h后所得的上清液对麦芽糖酶抑制活性最高,达37.36%,明显高于其它被测试的干酪乳杆菌菌株,表明该菌株具有潜在的抗高血糖作用。     

LiNO3 Addition to Prevent Hydrogen Gas Generation from Cement-Solidified Aluminum Wastes

LiNO₃ addition to the cement solidified miscellaneous wastes has been proposed for preventing hydrogen ges generation caused by the corrosion of aluminum materials contained in the wastes. To determine an additive among alkaline metal ions, galvanic current was measured in 0.1 M alkaline metal hydroxide solution between aluminum and platinum electrodes. The volume of hydrogen gas generated from an aluminum specimen was measured in a KOH solution with LiNO₃, LiCl, LiBr, Li₂CO₃ or Li₂SO₄ to decide the best additive. Applicability of the chosen additive to cement was confirmed by hydrogen gas generation measurement from an aluminum specimen in cement paste. The prevention mechanism was analyzed by X-ray diffraction, SEM and SIMS.

The current measured in LiOH solution decreased with time, then reached 0 μA/mm², while the current was detected in other alkaline metal hydroxide solutions. The least volume of hydrogen gas generation was measured in a KOH solution with LiNO₃. The volume of generated hydrogen gas in cement paste with LiNO₃ was less than 10% of that without LiNO₃. The results of analyses showed that an insoluble film of LiH(AlO₂)₂5H₂O was formed on the aluminum surface.

These results suggested that LiNO₃ addition to cement is effective to prevent hydrogn gas generation by formation of the insoluble film on aluminum.     

羟丙基壳聚糖与表面活性剂的缓蚀协同效应

目的研究羟丙基壳聚糖(HPCS)与Tw-20、十二烷基苯磺酸钠(SDBS)在1 mol/L HCl溶液中对Q235钢的协同缓蚀作用。方法进行Q235钢试片在1 mol/L HCl溶液中的腐蚀试验,通过失重法、动电位极化和电化学交流阻抗技术,分析HPCS及其与Tw-20,SDBS复配的缓蚀效果与机理。结果低浓度条件下,HPCS的缓蚀性能并不显著,100 mg/L时的缓蚀效率仅为63.03%,添加0.2 mg/L Tw-20可使50mg/L HPCS的缓蚀效率从51.73%提高到90.75%。当HPCS/Tw-20/SDBS以50,0.2,20 mg/L复配时,缓蚀效率高达93.77%,由于同时具备了非离子型和阴离子型表面活性剂的优点,其在60℃时缓蚀效率仍保持在71.11%。结论 Tw-20,SDBS对HPCS具有良好的协同缓蚀作用,HPCS/Tw-20和HPCS/Tw-20/SDBS复合缓蚀剂均为混合型缓蚀剂,作用机理为"几何覆盖效应"。     

赤铁矿石浮选抑制剂的应用现状及研发前景

主要介绍了赤铁矿石浮选中的三大类抑制剂:淀粉类抑制剂、纤维素类抑制剂和其它种类的抑制剂。总结了近年来各类抑制剂的研究成果,其中对赤铁矿传统抑制剂淀粉的抑制机理、使用方法及使用时的注意事项进行了简单介绍,并且对赤铁矿石抑制剂的研发前景作了分析。     

CHAMOMILE (Matricaria recutita) EXTRACT AS A CORROSION INHIBITOR FOR MILD STEEL IN HYDROCHLORIC ACID SOLUTION

The corrosion inhibition of mild steel in hydrochloric acid solution by chamomile (Matricaria recutita) extract (CE) was investigated through electrochemical (polarization, EIS) and surface analysis (optical microscopy/AFM/SEM) techniques. The effects of inhibitor concentration, temperature, and pH were evaluated. Thermodynamic parameters were calculated and adsorption studies were carried out. Finally, the surface morphology was investigated. The electrochemical studies showed that CE acts as a mixed-type corrosion inhibitor with predominantly anodic behavior. CE was adsorbed physically on the metal surface and obeyed the Langmuir adsorption isotherm. It impeded the corrosion processes by changing the activation energy. In the presence of CE, the metal surface was more uniform than the surface in the absence of inhibitor. Maximum inhibition efficiency (IE) was 93.28%, which was obtained at 22°C in 7.2 g/L of inhibitor in 1 M HCl solution.     

CORROSION INHIBITION OF STEEL PIPELINES IN OIL WELL FORMATION WATER BY A NEW FAMILY OF NONIONIC SURFACTANTS

A new family of nonionic surfactants was synthesized and evaluated as corrosion inhibitors for steel pipelines in oil well formation water. Polarization data show that the selected surfactants act as mixed-type inhibitors. EIS results show that the change in impedance parameters (R_t and C_dl) with the concentration of the surfactants studied is indicative of the adsorption of surfactant molecules on carbon steel surface, leading to formation of a good protective film. The properties of this film were studied by various surface analysis tools. Finally, the relation between the surface properties of the inhibitor molecules and corrosion inhibition efficiency is discussed.     

BENEFICIAL ROLE OF SURFACTANTS AS CORROSION INHIBITORS IN PETROLEUM INDUSTRY: A REVIEW ARTICLE

The objective of this review is to outline the beneficial role of surfactants as corrosion inhibitors in the petroleum field. After an introduction and brief notes on fundamentals of surfactants, the article shows the most important corrosion problems in the oil industry and the effective role of surfactants to solve these problems. The reported mechanisms of corrosion inhibition by surfactants are also considered. Key results are extracted from publications covering the past 50 years.     

β-糖苷酶抑制剂α-溴代丙酮-β-碳苷的简便合成

以廉价易得的醛糖为原料,利用高效、环保的1,3-二溴-5,5-二甲基海因(DBDMH)为溴化试剂,经过碳苷化和α-溴代反应,两步法简便合成了标题化合物,两步总产率分别为60%、56%和48%,高于文献值。