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601.
Organic matter content of sediments in continental shelf area of southeast coast of India 总被引:1,自引:0,他引:1
Syed Ajmal Khan K. G. Mohamed Thameemul Ansari P. Somasundharanair Lyla 《Environmental monitoring and assessment》2012,184(12):7247-7256
Total organic matter (TOM) content of sediment samples collected from various depths of continental shelf region of the southeast coast of India varied from 0.19% to 7.73%. Higher TOM content and lower median particle diameter could be attributed to the influence of higher riverine flow. Higher values were observed at 100?m depth and above (average 5.29%) and lower values in shallower depths below 100?m (average 3.07%). In the Principal Coordinate Analysis (PCO), the first two axes explained about 83.1% of the total variability. The direction of the vector representing total organic matter was towards 150?m depth. In the Canonical Analysis of Principal Coordinates (CAP) done to confirm the above pattern, the canonical correlation value obtained for the first axis was high (0.9999). The same for the second axis was 0.9995. The direction of the axis representing TOM in this analysis was towards the 100?m depth truly reflecting higher TOM level recorded here (average TOM at 100?m depth—5.81% and at 150?m depth—5.33%). The percentage of samples allocated to the correct group in CAP was 91.67% (33 out of the 36 samples). As the allocation success of samples is substantially greater around 92%, the CAP is explaining greater percentage of variability of TOM than PCO and was found to be quite useful for studies of this nature. 相似文献
602.
Vinay Kumar Tyagi Akanksha Bhatia Rubia Zahid Gaur Abid Ali Khan Muntajir Ali Anwar Khursheed Absar Ahmad Kazmi 《Environmental monitoring and assessment》2012,184(12):7517-7529
The present study investigated the effects of heavy metals (Ni, Zn, Cd, Cu, and Pb) toxicity on the performance of 18 MLD activated sludge process-based sewage treatment plant (STP) during celebration of Holi (festival of colors in India). The composite sampling (n?=?32) was carried out during the entire study period. The findings show a significant decrease in chemical oxygen demand removal efficiency (20%) of activated sludge system, after receiving the heavy metals laden wastewater. A significant reduction of 40% and 60% were observed in MLVSS/MLSS ratio and specific oxygen uptake rate, which eventually led to a substantial decrease in biomass growth yield (from 0.54 to 0.17). The toxic effect of metals ions was also observed on protozoan population. Out of the 12 mixed liquor species recorded, only two ciliates species of Vorticella and Epistylis exhibited the greater tolerance against heavy metals toxicity. Furthermore, activated sludge shows the highest metal adsorption affinity for Cu, followed by Zn, Pb, Ni, and Cd (Cu?>?Zn?>?Pb?>?Ni?>?Cd). Finally, this study proves the robustness of activated sludge system against the sudden increase in heavy metal toxicity since it recovered the earlier good quality performance within 5?days. 相似文献
603.
Lutfullah Farheen Khan Nafisur Rahman 《Environmental monitoring and assessment》2013,185(6):4959-4967
The present study reports on the application of modified groundnut shell as a new, easily prepared, and stable sorbent for the extraction of trace amount of Cr(III) in aqueous solution. 2-Hydroxybenzaldiminoglycine was immobilized on groundnut shells in alkaline medium and then used as a solid phase for the column preconcentration of Cr(III). The elution was carried out with 3 mL of 2 mol?L?1 HCl. The amount of eluted Cr(III) was determined by spectrophotometry using cefaclor as a complexing reagent and by flame atomic absorption spectrometry (FAAS). Different experimental variables such as pH, amount of solid sorbent, volume and concentration of eluent, sample and eluent flow rate, and interference of other metal ions on the retention of Cr(III) were studied. Under the optimized conditions, the calibration curves were found to be linear over the concentration range of 13–104 and 10–75 μg?L?1 with a detection limit of 3.64 and 1.24 μg?L?1 for spectrophotometric method and FAAS, respectively. An enrichment factor of 200 and RSD of ±1.19–1.49 % for five successive determinations of 25 μg?L?1 were achieved. The column preconcentration was successfully applied to the analysis of tap water and underground water samples. 相似文献
604.
605.
Raquibul Alam Julie Q. Shang Adnan Hossain Khan 《Environmental monitoring and assessment》2017,189(4):193
The performance of electroflotation (EF) is strongly influenced by the size of O2 and H2 bubbles. Therefore, in this study, the bubble sizes are measured in a lab-scale EF cell using a high-speed camera. The mean bubble size is found to vary in the range of 32.7–68.6 μm under different operating conditions. This study shows that the electrode material, current density, water pH, ionic strength, and frother (Tennafroth 250) concentration are important factors in controlling the bubble size. Furthermore, four mathematical distributions (normal, log-normal, Weibull, and gamma distributions) are fitted to the experimental data, among which the log-normal distribution is found to be the best fit based on the lower Anderson-Darling (AD) value. 相似文献
606.
Farhana Gul-E-Noor Mubarak A. Khan Sushanta Ghoshal Ruhul A. Khan Russel A. Mazid A. M. Sarwaruddin Chowdhury 《Journal of Polymers and the Environment》2010,18(3):224-230
Thin films of gelatin were prepared by casting. Then the films were photocured and the mechanical properties were studied.
The tensile strength of UV cured gelatin films showed about 10% enhancement than that of raw gelatin films. Minor amount of
urea (1–5%) was used as additive in aqueous gelatin solution and films were prepared using same technique. Four formulations
were prepared in methanol with 2-ethylhexyl acrylate in the presence of photoinitiator (darocur-1664). The films were soaked
in the prepared formulations and then cured under UV radiation at different intensities (5–25 passes). Percentage of urea,
monomer concentration, soaking time and radiation intensities were optimized with the extent of polymer loading, TS and elongation
at break of the photocured film. The films containing 2% urea, cured with 3% EHA for 3 min at 15th UV pass showed the highest
mechanical properties. A significant improvement of TS (31%) occurred when EHA (3%) was incorporated. 相似文献
607.
Fahmida Parvin Mubarak A. Khan A. H. M. Saadat M. Anwar H. Khan Jahid M. M. Islam Mostak Ahmed M. A. Gafur 《Journal of Polymers and the Environment》2011,19(4):1013-1022
Blends based on different ratios of starch (35–20%) and plasticizer (sugar; 0–15%) keeping the amount of poly(vinyl alcohol)
(PVA) constant, were prepared in the form of thin films by casting solutions. The effects of gamma-irradiation on thermal,
mechanical, and morphological properties were investigated. The studies of mechanical properties showed improved tensile strength
(TS) (9.61 MPa) and elongation at break (EB) (409%) of the starch-PVA-sugar blend film containing 10% sugar. The mechanical
testing of the irradiated film (irradiated at 200 Krad radiation dose) showed higher TS but lower EB than that of the non-radiated
film. FTIR spectroscopy studies supported the molecular interactions among starch, PVA, and sugar in the blend films, that
was improved by irradiation. Thermal properties of the film were also improved due to irradiation and confirmed by thermo-mechanical
analysis (TMA), differential thermo-gravimetric analysis (DTG), differential thermal analysis (DTA), and thermo-gravimetric
analysis (TGA). Surface of the films were examined by scanning electron microscope (SEM) image that supported the evidence
of crosslinking obtained after gamma irradiation on the film. The water up-take and degradation test in soil of the film were
also evaluated. In this study, sugar acted as a good plasticizing agent in starch/PVA blend films, which was significantly
improved by gamma radiation and the prepared starch-PVA-sugar blend film could be used as biodegradable packaging materials. 相似文献
608.
Ali I Khan TA Asim M 《Environmental science and pollution research international》2012,19(5):1668-1676
Purpose
Arsenic, a toxic metalloid in drinking water, has become a major threat for human beings and other organisms. In the present work, attempts have been made to remove arsenate from the synthetic as well as natural water of Ballia district, India by electrocoagulation method. Efforts have also been made to optimize the various parameters such as initial arsenate concentration, pH, applied voltage, processing time, and working temperature.Method
Electrocoagulation is a fast, inexpensive, selective, accurate, reproducible, and eco-friendly method for arsenate removal from groundwater. The present paper describes an electrocoagulation method for arsenate removal from groundwater using iron and zinc as anode and cathode, respectively.Results
The maximum removal of arsenate was 98.8% at 2.0?mg?L?1, 7.0, 3.0?V, 10.0?min, and 30°C as arsenate concentration, pH, applied voltage, processing time, and working temperature, respectively. Relative standard deviation, coefficient of determination (r 2), and confidence limits were varied from 1.50% to 1.59%, 0.9996% to 0.9998%, and 96.0% to 99.0%, respectively. The treated water was clear, colorless, and odorless without any secondary contamination. The developed and validated method was applied for arsenate removal of two samples of groundwater of Ballia district, U.P., India, having 0.563 to 0.805?mg?L?1, arsenate concentrations.Conclusions
The reported method is capable for the removal of arsenate completely (100% removal) from groundwater of Ballia district. There was no change in the groundwater quality after the removal of arsenate. The treated water was safe for drinking, bathing, and recreation purposes. Therefore, this method may be the choice of arsenate removal from natural groundwater. 相似文献609.
Khan Umair Liu Weili 《Environmental science and pollution research international》2023,30(13):36160-36175
Environmental Science and Pollution Research - The research uses human resources management ability and practice, opportunity and motivation (AMO) concept and CSR, environmental responsibility and... 相似文献
610.
Rashid Md. Ehsanur Khan Md. Rubel Haque Raihan Ul Hasanuzzaman Md. 《Journal of Material Cycles and Waste Management》2023,25(3):1267-1287
Journal of Material Cycles and Waste Management - Every year, a massive volume of textile waste is disposed of in a landfill or incinerated, contributing to resource loss and environmental... 相似文献