Sustainable green technology on wastewater treatment: The evaluation of enhanced single chambered up-flow membrane-less microbial fuel cell

This study demonstrated the potential of single chamber up-flow membrane-less microbial fuel cell(UFML-MFC) in wastewater treatment and power generation. The purpose of this study was to evaluate and enhance the performance under different operational conditions which affect the chemical oxygen demand(COD) reduction and power generation,including the increase of KCl concentration(MFC1) and COD concentration(MFC2). The results showed that the increase of KCl concentration is an important factor in up-flow membrane-less MFC to enhance the ease of electron transfer from anode to cathode. The increase of COD concentration in MFC2 could led to the drop of voltage output due to the prompt of biofilm growth in MFC2 cathode which could increase the internal resistance. It also showed that the COD concentration is a vital issue in up-flow membrane-less MFC.Despite the COD reduction was up to 96%, the power output remained constrained.     

Identification and quantification of bisphenol A by gas chromatography and mass spectrometry in a lab-scale dual membrane system

Endocrine disruptor contamination is an emerging issue of concern in the field of water quality engineering. In this study, a lab-scale microfiltration (MF) and reverse osmosis (RO) based water reclamation system was set up to monitor and evaluate the removal of bisphenol A (BPA), which is a known oestrogenic compound. The identification and quantification of BPA were performed by using gas chromatography coupled with mass spectrometry. It was noted that the detection method used in this study was able to achieve an average recovery ranging from 88.2 to 94.1% of BPA with standard deviations of less than 10% in different spiked samples. The detection limit of the analytical protocol was determined at 20 ng L(-1). Based on the analytical protocol, it was noted that a low level of BPA (1.18-3.04 microg L(-1)) could be detected in feed water (effluent of an activated sludge treatment system) to the dual membrane water reclamation system. The results obtained suggested that BPA could be easily chlorinated by sodium hypochlorite with a dosage of 4 to 5 mg L(-1) and a contact time of 1 to 2 min. In this lab-scale study, a satisfactory removal of BPA was readily obtained by RO and BPA was abated to an undetectable level in the product water. It was noted that the RO rejection characteristic of BPA was not sensitive to the variations in raw feed water characteristics experienced in this study. In addition, it was noted that BPA concentration present in raw feed water did not exert any significant impact on RO performance in terms of BPA rejection. The results of this study demonstrated that membrane technology could be effectively used for BPA removal.     

Determination of Carcinogenic Heterocyclic Amines in Satay by Liquid Chromatography

The successful determination of mutagenic/carcinogenic heterocyclic amines (HCAs) in trace amounts (ng/g, ppb levels) in commercial foods depends largely on the detection sensitivity and selectivity, as well as the quality of clean-up of complex food matrices. In the present study, UV and fluorescence detection in series with gradient elution HPLC was used for the separation and determination of eight HCAs present in a local delicacy, satay. The identification of peaks was carried out by UV diode-array spectrophotometry. The most common HCA found in all types of satay (chicken, mutton, pork) cooked under Chinese and Malay styles was 2-amino-9H-pyrido[2,3-b]indole (AC) (1.3-12 ppb) while 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) was found at comparatively high levels (78 ppb) in both Chinese-style pork and Malay-style chicken satay. Other major HCAs included 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) (non-detectable (ND) to 31 ppb), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) (ND-12 ppb) and 2-aminodipyrido[1,2-a:3,2-d]-imidazole (Glu-P-2) (ND-25 ppb). Comutagen norharman (NH) was also detected at levels up to 84 ppb, while harman (H) was only detected in one sample (Chinese-style pork satay), at a level of 25 ppb. The differences in the type and level of HCAs in satay samples may be attributed to the variation in raw foodstuffs cooked under different styles by Chinese or Malay vendors, and the ingredients added during cooking.     

Climate change: linking adaptation and mitigation through agroforestry

Agriculture is the human enterprise that is most vulnerable to climate change. Tropical agriculture, particularly subsistence agriculture is particularly vulnerable, as smallholder farmers do not have adequate resources to adapt to climate change. While agroforestry may play a significant role in mitigating the atmospheric accumulation of greenhouse gases (GHG), it also has a role to play in helping smallholder farmers adapt to climate change. In this paper, we examine data on the mitigation potential of agroforestry in the humid and sub-humid tropics. We then present the scientific evidence that leads to the expectation that agroforestry also has an important role in climate change adaptation, particularly for small holder farmers. We conclude with priority research questions that need to be answered concerning the role of agroforestry in both mitigation and adaptation to climate change.     

Maternal serum levels of total activin-A in first-trimester trisomy 21 pregnancies

Maternal serum total activin-A concentration was measured in 45 pregnancies affected by trisomy 21 and 493 control unaffected pregnancies at 10–14 weeks of gestation. In the trisomy 21 pregnancies total activin-A concentration was significantly higher (1.36 MoM of the unaffected pregnancies) and in 16% of cases the level was above the 95th centile of normal. The log₁₀ SD for the control group and the trisomy 21 group were 0.17 and 0.22, respectively. The median pregnancy associated plasma protein-A (PAPP-A) in this trisomy 21 series was 0.49 and for free β-hCG was 2.05. In the trisomy group there were significant positive associations between total activin-A and PAPP-A (0.6071) and free β-hCG (0.4255). The low median difference and the high overlap in values between trisomic and unaffected pregnancies make total activin-A of little practical use in first-trimester screening for trisomy 21. Copyright © 2001 John Wiley & Sons, Ltd.     

An optimization procedure for the isocratic high-performance liquid chromatographic separations of environmental pollutants

This paper describes the use of the overlapping resolution mapping procedure to optimize the separation of priority pollutants by isocratic, reversed-phase high-performance liquid chromatography. Three classes of pollutants are considered: polycyclic aromatic hydrocarbons, substituted phenols and phthalate esters. The procedure requires only seven chromatographic runs for each set of pollutants before an optimized mobile phase composition is derived which can satisfactorily resolve all the components in the respective mixtures of pollutants. The main advantage of such a systematic scheme to optimize mobile phase compositions is an improvement in method development times compared to conventional techniques. Another benefit is that expenditures on solvents are reduced.     

Optimization of the gradient HPLC separation of selected phthalates using the overlapping resolution mapping technique

Optimization procedures for the reversed-phase separations of six phthalates using the isoselective multisolvent gradient elution (IMGE) system are described. A systematic experimental design has been employed to gather retention data on the compounds in a mixture. The data were then fitted into a second-order polynomial equation and an overlapping resolution mapping (ORM) technique of data analysis was subsequently used to establish the optimum solvent mixture for the highest resolution of all adjacent peaks in the chromatogram.     

双酚A暴露对斑马鱼胚胎期代谢作用的影响

运用基于GC/MS的代谢组学方法,以受精卵在双酚A(BPA)中暴露4d后的斑马鱼胚胎为对象,研究了其体内挥发性和半挥发性代谢组分变化.暴露浓度设定为0,0.5,1.5,4.5mg/L,包括US EPA假定的“安全水平”(1.5mg/L).结果表明,1.5mg/L BPA暴露能使斑马鱼体内花生四烯酸和胆固醇的相对百分含量极显著降低,饱和脂肪酸、氨基酸、葡萄糖和肌糖的相对百分含量显著升高.因此,1.5mg/L BPA能干扰斑马鱼胚胎期的正常代谢.     

Application of proteomics in environmental science

Proteomics involves the separation of proteins, identification of the amino acid sequence of the interested or target proteins, study of the function of the proteins, modification, structure and ultimate assignments to functional pathways in the cell. The proteomic investigations have contributed greatly to human diseases studies, new drugs discovery researches, and environmental science in recent years. This article provides a review on the development of the main proteomic technologies, including both the gel based and non-gel based technologies, and their applications in environmental science. Proteomic technologies have been utilized in the environmental stresses studies to analyze the induction or reduction of proteins at expression level and identify the target proteins to investigate their function in response to environmental stresses, such as high or low pH, oxidation stress, and toxic chemicals. Such protein responses are also helpful to understand the mechanisms of some cellular activities and the functions of some proteins.     

Carbon dioxide electroreduction into formic acid and ethylene: a review

Environmental Chemistry Letters - Climate change damage induced by growing carbon dioxide (CO2) emissions has rapidly fostered research on capturing, utilizing, and converting CO2 into valuable C1...