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Removal of Cu and Ni by Free and Immobilized Microalgae

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Biomedical and Environmental Sciences 1992年第2期5卷 99-108页

作者： M.H.WONG D.C.H.PAK department of biology Hong Kong Baptist College 224 Waterloo Road KowloonDepartment of Biology Hong Kong Baptist College 224 Waterloo Road Kowloon Hong KongHong Kong

The present investigation evaluated the effectiveness of Chlorella cells in concentrating Cu and Ni in their cells and thereby removing the two metals from solution. The removal efficiency of the two metals by free and immobilized algal cells were further studied. (1) Four types of Chlorella cells, namely Chlorella pyrenoidosa (26) (from Carolina Biological Supplies Company), Chlorella HKBC-1 and-2 (isolated from a polluted stream receiving wastewater from several electroplating factories) and Chlorella HKBC-3 (from a clean water pond) were subjected to different concentrations of Cu and Ni accordingly. It was revealed that Chlorella HKBC-1 was the most tolerant species toCu and Ni as reflected by their highest values of 48 h and 96 h 'Highest no effect concentrations' (The highest concentration of the tested substance that does not inhibit the growth rate of the alga: Cu 2 and Ni 10 mg/1 at 48 h, Cu 2 and Ni 5 at 96 h). This was followed by C. pyrenoidosa (26) and then C. HKBC-2 while C. HKBC-3 had the lowest tolerance to the two metals (Cu 0.5 and Ni 2 at 48 h; Cu 0.5 and Ni 1 mg/1 at 96 h). (2) It was further revealed that C. HKBC-1 had higher concentration factors and removal efficiencies of Ni (734-963 mg/1, 16.3-18.7%) and C. HKBC-2 had higher concentration factors and removal efficiencies of Cu (2316-2839 mg/1, 53.7-66%) when exposed to lower concentrations of Cu (0.5,1 and 2 mg/1) and Ni (5, 10 and 13 mg/1). (3) By treating the free and immobilized algal cells (algal cells entrapped in alginate beads) with different concentrations of Cu and Ni, it was observed that free cells had higher concentration factors and removal efficiencies when compared with immobilized cells (free cells: Cu 1577-3056 mg/1, 24.2-71.4%; Ni 355-849 mg/1, 4.8-18.7%; immobilized cells: Cu 453-935 mg/1, 13.9-53.2%; Ni 244-486 mg/1, 3.2-11.9%).

关键词： Removal of Cu and Ni by Free and Immobilized Microalgae Cu Ni

Characterizing the optimal operation of photocatalytic degradation of BDE-209 by nano-sized TiO_2

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Journal of Environmental Sciences 2012年第9期24卷 1670-1678页

作者： Ka Lai Chow Yu Bon Man Jin Shu Zheng Yan Liang Nora Fung Yee Tam Ming Hung Wong Croucher Institute for Environmental Sciences and Department of Biology Hong Kong Baptist University Hong Kong SAR China department of biology and Chemistry City University of Hong Kong Hong Kong SAR China

Brominated flame retardants have been widely used in industry. There is a rapid growing public concern for their availabilities in the environment. Advanced oxidation process （AOP） is a promising and efficient technology which may be used to remove emerging chemicals such as brominated flame retardants. This study aims at investigating optimal operational conditions for the removal of BDE-209 using nano-scaled titanium（IV） oxide. The residual PBDE congeners after photocatalytical degradation of BDE-209 by TiO2 were analysed by gas chromatography-mass spectrometry （GC-MS）. It was found that the degradability of BDE-209 by TiO2 was attributed to its photocatalytic activity but not the small size of the particles. The half-life of removing BDE-209 by TiO2 was 3.05 days under visible light. Tetra- and penta-BDEs were the major degraded products of BDE-209. Optimum conditions for photocatalytical degradation of BDE-209 was found to be at pH 12 （93% ± 1%）, 5, 10, 20 mg/L （93.0% ± 1.70%, 91.6% ± 3.21%, 91.9% ± 0.952%, respectively）, respectively of humic acid and in the form of anatase/rutile TiO2 （82% ± 3%）. Hence, the efficiency of removing BDE-209 can be maximized while being cost effective at the said operating conditions.

关键词： PBDEs TiO2 photocatalysis hydroxyl radicals

Residues of Polychlorinated Biphenyls (PCBs) in Fish, Water and Sediment from Shing Mun River

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Biomedical and Environmental Sciences 1991年第4期4卷 399-408页

作者： V.W.D.CHUI T.C.CHAN S.Y.LAM-LEUNG department of biology hong kong baptist college 224 Waterloo Road Kowloon Hong KongDepartment of Biology Hong Kong Baptist College 224 Waterloo Road Kowloon Hong KongDepartment of Chemistry Hong Kong Baptist College 224 Waterloo Road Kowloon Hong Kong

The level and pattern of contamination by polychlorinated biphenyls (PCBs) were investigated in tilapia, Oreochromis mossambicus (Peters), sediment, and water from the Shing Mun River. The range of total PCBs was 12.9 ng/g to 181.6 ng/g wet weight in tilapia, 12.7 ng/g to 46.0 ng/g freeze-dried weight in sediment, and 3.8 ng/L to 13.6 ng/L in water. The effect of biomagnification was also observed, PCB concentrations increased from water to sediment to tilapia. PCB congeners occurred in such a way that lower chlorinated PCBs comprised a higher fraction of the total PCBs in water, sediment, and tilapia muscle, whereas higher chlorinated PCBs were more commonly found only in tilapia.

关键词： PCBs Residues of Polychlorinated Biphenyls Water and Sediment from Shing Mun River in Fish

Decontamination of Landfill Leachate by Soil Infiltration

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Biomedical and Environmental Sciences 1989年第4期2卷 341-357页

作者： M.H.WONG K.C.LEUNG department of biology Hong Kong Baptist CollegeKowloonHong Kong department of biology The Chinese University of Hong KongShatinHong Kong

A soil column study was conducted to evaluate the efficiency of soil to attenuate pollutants in landfill *** was found that more than 60% of the initial alkalinity,COD,and total nitrogen was removed after the leachate had percolated through the soil *** effi- ciencies were observed for the removal of dissolved cations,ammonia nitrogen,and nitrate *** previously percolated leachate was recirculated through the soil column,sig- nificant removal(93.6%)of ammonia nitrogen was ***,a further reduction in COD,total nitrogen,nitrate nitrogen,and potassium was *** tests of seed germi- nation and root growth of Brassica chinensis were performed to compare the phytotoxicities of untreated,percolated,and recirculated *** phytotoxicity was reduced by both treatments,with the greatest detoxification observed in the leachate recirculation *** values ofpH and Olsen phosphorus were significantly reduced(P<0.01)in the treated column *** significant increases(P<0.05)in electrical conductivity(EC),various forms of nitrogen,exchangeable sodium percentage(ESP),potassium,magnesium,zinc,and iron were ***,ESP,potassium,magnesium,sodium,iron,and various forms of nitrogen accu- mulated at the soil surface(10 cm).On the other hand,manganese was deposited at 20 to 50 cm below the soil surface of the treated column.1989 Academic ***.

关键词：刀口井群

Removal of Lead from Aqueous Solution by Acinetobacter calcoaceticus

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Biomedical and Environmental Sciences 1990年第2期3卷 202-210页

作者： N.K.MAK Y.K.MOK V.W.D.CHUI M.H.WONG department of biology Hong Kong Baptist College 224 Waterloo Road Hong Kong

A bacterial strain tolerant to the presence of 400 ppm lead was isolated from digested sewage sludge. The organism was identified as Acinetobacter calcoaceticus var: anitraus (98% confidence). Both viable and formalin-inactivated bacterial cells could remove Pb from an aqueous solution. The Pb-binding ability of inactivated cells was compared with that of a commercial ion-exchange resin, Amberlite IR-I20. The metal-binding ability of A. calcoaceticus followed the sequence Pb≥Cu≥Cr≥ (Cd, Ni, and Zn)≥Co. The ability of the inactivated cells to remove Pb was pH sensitive, and the adsorption process was slightly affected at high temperature (70℃). The adsorption and desorption process worked equally well with A. calcoaceticus embedded in a polyacrylamide gel matrix. (c)1990 Academic Press, Inc.

关键词：柳人

The Effects of Organic Ligands on the Survival of Daphnia in Zn Solution

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Biomedical and Environmental Sciences 1991年第4期4卷 433-440页

作者： M.H.WONG department of biology Hong Kong Baptist College 224 Waterloo Road Kowloon Hong Kong

Bioassays involving zinc alone and in combinations with two organic ligands, namely histidine and EDTA were conducted on Daphnia longispina over a period of 96 h. The percentage of mortality was recorded and the Median Lethal Concentration (LC50) at 96 h estmated. The 96 h LC50 of D. longispina in zinc solution was 91 μg/1 whereas no values of LC50 were revealed when D. longispina were exposed to histidine or EDTA alone although the organic ligands seemed to exert harmful effects (e.g. The mortality at 96 h was 18% at a concentration of 10×10^(-5) M histidine and 16% at a concentration of 6×10~6 M EDTA). However, addition of histidine and EDTA effectively reduced the toxicity of zinc to the test animals. The detoxification effect was the most obvious at the concentration of 100×g/1 Zn added with 5×10^(-5) M histidine and 3×10^(-6) M EDTA where 7-fold and 5-fold reduction in terms of mortality were noted.

关键词： Zn

Lead Concentration in hong kong Roadside Dust after Reduction of Lead Level in Petrol

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Biomedical and Environmental Sciences 1989年第2期2卷 131-140页

作者： G.Y.S.CHAN V.W.D.CHUI M.H.WONG department of biology Hong Kong Baptist College224 Waterloo RoadKowloonHong Kong

Samples of roadside dust were collected from 30 sites in hong *** total concentrations of 10 metals in the samples were analyzed,and the correlation coefficients among the metal contents and the annual average daily traffic(AADT)in 1986 were *** was found to have a significant correlation(P<0.01)with *** correlation was found between Al, Ba,Cd,Cr,Cu,Fe,Mn,Ni,and Zn with respect to AADT.A general decrease in the level of Pb in roadside dust in the past few years has been observed since the reduction in the level of lead in petrol.1989 Academic Press,Inc.

关键词： Ho In Ba Lead Concentration in hong kong Roadside Dust after Reduction of Lead Level in Petrol Pb

Aerenchyma Formed Under Phosphorus Deficiency Contributes to the Reduced Root Hydraulic Conductivity in Maize Roots

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Journal of Integrative Plant biology 2007年第5期49卷 598-604页

作者： Mingshou Fan Ruiqin Bai Xuefeng Zhao Jianhua Zhang college of Agronomy Inner Mongolia Agricultural University Huhhot 010018 China department of biology Hong Kong Baptist University Hong Kong China

Root hydraulic conductivity has been shown to decrease under phosphorus （P） deficiency. This study Investigated how the formation of aerenchyma is related to this change. Root anatomy, as well as root hydraulic conductivity was studied In maize （Zea mays L.） roots under different phosphorus nutrition conditions. Plant roots under P stress showed enhanced degradation of cortical cells and the aerenchyma formation was associated with their reduced root hydraulic conductivity, supporting our hypothesis that air spaces that form in the cortex of phosphorusstressed roots Impede the radial transport of water in a root cylinder. Further evidence came from the variation In aerenchyma formation due to genotypic differences. Five maize inbred lines with different porosity in their root cortex showed a significant negative correlation with their root hydraulic conductivity. Shoot relative water content was also found lower In P-deficient maize plants than that in P-sufficient ones when such treatment was prolonged enough, suggesting a limitation of water transport due to lowered root hydraulic conductivity of P-deficient plants.

关键词： aerenchyma maize (Zea mays) phosphorus deficiency root root hydraulic conductivity.

Biodegradation of aniline by Candida tropicalis AN1 isolated from aerobic granular sludge

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Journal of Environmental Sciences 2011年第12期23卷 2063-2068页

作者： Dianzhan Wang Guanyu Zheng Shimei Wang Dewei Zhang Lixiang Zhou department of Environmental Engineering College of Resources and Environmental Sciences Nanjing Agricultural University Nanjing 210095 China department of biology Hong Kong Baptist University Hong Kong 999077 China

Aniline-degrading microbes were cultivated and acclimated with the initial activated sludge collected from a chemical wastewater treatment plant. During the acclimation processes, aerobic granular sludge being able to effectively degrade aniline was successfully formed, from which a preponderant bacterial strain was isolated and named as AN1. Effects of factors including pH, temperature, and second carbon/nitrogen source on the biodegradation of aniline were investigated. Results showed that the optimal conditions for the biodegradation of aniline by the strain AN1 were at pH 7.0 and 28–35°C. At the optimal pH and temperature, the biodegradation rate of aniline could reach as high as 17.8 mg/（L·hr） when the initial aniline concentration was 400 mg/L. Further studies revealed that the addition of 1 g/L glucose or ammonium chloride as a second carbon or nitrogen source could slightly enhance the biodegradation efficiency from 93.0% to 95.1%–98.5%. However, even more addition of glucose or ammonium could not further enhance the biodegradation process but delayed the biodegradation of aniline by the strain AN1. Based on morphological and physiological characteristics as well as the phylogenetic analysis of 26S rDNA sequences, the strain AN1 was identified as Candida tropicalis.

关键词： aniline aerobic granular sludge biodegradation Candida tropicalis AN1