Antioxidant and Cytotoxic Activities of Exopolysaccharides from Alcaligenes faecalis Species Isolated from the Marine Environment of Mauritius

Journal of Polymers and the Environment - Extracellular polysaccharides (EPS) of microbial origin are polymers with great potential for research and industrial applications. In this study, a...     

Project risk identification and assessment simultaneously using multi-attribute group decision making technique

The identification and assessment of project risks among potential risks can be considered a multi-attribute group decision making (MAGDM) problem including both quantitative and qualitative criteria. We extend the concept of safety to risk identification and assessment; this is to emphasize that the focus should not only be on the time and cost criteria, but also on the health, safety and environment (HSE) criterion. Conventional approaches to risk identification and risk assessment separately tend to be less effective in dealing with the imprecise of the risk assessment individually. The aim of this paper is to present a new methodology for identifying and assessing risks simultaneously by applying MAGDM technique. This paper includes a new procedure for classifying potential risks which it is named potential risk breakdown structure (PRBS) based on project work breakdown structure (WBS). Nominal group technique (NGT) is utilized for gathering potential risks. Obtained results have been applied in gas refinery plant construction successfully.     

Kinetic of formation for single carbon dioxide and mixed carbon dioxide and tetrahydrofuran hydrates in water and sodium chloride aqueous solution

A laboratory-scale reactor system is built and operated to measure the kinetic of formation for single and mixed carbon dioxide–tetrahydrofuran hydrates. The T-cycle method, which is used to collect the kinetic data, is briefly discussed. For single carbon dioxide hydrate, the induction time decreases with the increase of the initial carbon dioxide pressure up to 2.96 MPa. Beyond this pressure, the induction time is becoming relatively constant with the increase of initial carbon dioxide pressure indicating that the liquid phase is completely supersaturated with carbon dioxide. Experimental results show that the inclusion of tetrahydrofuran reduces the induction time required for hydrate formation. These observations indicate hydrate nucleation process and onset growth are more readily to occur in the presence of tetrahydrofuran. In contrast, the presence of sodium chloride prolongs the induction time due to clustering of water molecules with the ions and the salting-out effects. It is also shown that the degree of subcooling required for hydrate formation is affected by the presence of tetrahydrofuran and sodium chloride in the hydrate forming system. The presence of tetrahydrofuran in the hydrate system significantly reduces the amount of carbon dioxide uptake. The apparent rate constant, k, for those systems are reported.     

The development of low cost adsorbents from clay and waste materials: a review

Increased energy consumption due to industrial growth has increased the levels of carbon dioxide (CO₂) emission being released into the atmosphere. CO₂ emission is a type of greenhouse gas which is a major cause of global warming. Since the issue of CO₂ emissions has drawn much attention in recent years, the development of CO₂ capture technology has become a necessity. Although CO₂ adsorbents are still at the early development stage, it has been suggested that CO₂ adsorbents are the most effective technology in controlling CO₂ emissions. Solid adsorbents have great potential as an alternative method to conventional adsorbents in adsorbing CO₂. In this paper, low cost adsorbents including activated carbon, zeolites, mesoporous silica and clays are discussed in terms of adsorbent preparation methods and CO₂ adsorption capacity. The low cost adsorbents are mainly derived from waste materials such as fly ash, steel slag, red mud, bagasses wastes and wood wastes. Besides that, natural resources such as clays have also been applied as low cost CO₂ adsorbents. Surface modifications have also been applied to the low cost adsorbents, including metal ion exchange and amine impregnation to enhance CO₂ adsorption capacity. In the last section, the current status of CO₂ adsorbents is summarized and future trends are discussed briefly to predict the potential materials which can be applied as CO₂ adsorbents.     

气提式三重循环生物膜反应器处理制药废水中的甾体雌激素

为验证气提式三重循环生物膜反应器处理甾体雌激素的效能,建立了一套SPE/HPLC/MS/MS分析方法,对反应器进、出水中的甾体雌激素--甾酮(E1),17β-雌二醇(E2),雌三醇(E3)以及17α-乙炔基雌二醇(EE2)进行检测.该方法的加标回收率为88%～103%,精密度为4%～9%.该方法对E1,E2,E3和EE2的进水定量限(LOQ)分别为0.7,0.8,0.9和0.5 ng/L;对出水的定量限分别为2.0,1.0,2.0和 1.0 ng/L.CODCr和氨氮容积负荷最高为7.5和1.6 kg/(m3·d),出水依然能够保持稳定.进水pH稳定在9.0～10.5,而反应器的pH一直稳定在9.0以下,体系对pH变化造成的冲击比较适应.同时,反应器内形成了稳定的NO2--N积累,CODCr和氨氮的去除率分别达到了70%和73%.