Sawdust: Cost Effective Scavenger for the Removal of Chromium(III) Ions from Aqueous Solutions     

Rashid Ahmad 《Water, air, and soil pollution》2005,163(1-4):169-183

Cr(III) ions sorption onto sawdust of spruce (Picea smithiana) has been studied thoroughly using radiotracer technique. Maximum sorption (94%) of Cr(III) ions (8.98×10^?5 M) onto sorbent surface is achieved from deionized water in 20 min agitation time using 200 mg of sawdust. The sorption data followed the Freundlich, Dubinin-Radushkevich (D-R) and Langmuir isotherms. Freundlich constants l/n = 0.86 ± 0.07 and C _e = 85.0 ± 25.8 mmole g^?1 have been estimated. Sorption capacity, X _m = 0.82± 0.3 mmole g^?1, β = ?0.00356± 0.00017 kJ² mole^?2 and energy, E = 11.9± 0.3 kJ mole^?1 have been evaluated using D-R isotherm. The Langmuir constants Q = 5.8± 0.2 μmole g^?1 and b = (7.4± 0.5)×10⁴ dm³ mole^?1 have been calculated. The variation of sorption with temperature yields thermodynamic parameters Δ H = ?11.6± 0.3 kJ mole^?1, Δ S = ?16.2± 0.9 J mole^?1 K^?1 and Δ G = ?6.8± 0.3 kJ mole^?1 at 298 K. The negative value of enthalpy and free energy reflect the exothermic and spontaneous nature of sorption respectively. Among the anions studied oxalate, citrate, carbonate and borate have reduced the sorption. The cations Y(III), Ce(II) and Ca(II) suppressed sorption. The sawdust column can be used to separate Cr(III) ion from Cs(I), I(I),Tc (VII) and Se (IV).  相似文献   

Development of Empirical Formulae to Determine Emission Rate from Various Opencast Coal Mining Operations     

Chaulya  S. K.  Chakraborty  M. K.  Ahmad  M.  Singh  R. S.  Bondyopadhay  C.  Mondal  G. C.  Pal  D. 《Water, air, and soil pollution》2002,140(1-4):21-55

All major mining activities, particularly opencast coal mining,directly or indirectly contribute to the problem of air pollution.Therefore, air quality assessment and prediction arerequired to prevent and minimize the air quality deteriorationdue to various opencast coal mining operations. Determination ofemission rates for these activities is the first and foremostconcern. In view of the above, this study was undertaken to determinate emission rates and to develop empericalformulae to calculate emission rates of various opencast coalmining activities.To achieve the objectives, seven coal mining sites were selectedto generate site-specific emission data by considering miningpractices, method of working, geographical location,accessibility and above all resourceavailability. The study covers various mining activities andlocations including drilling, overburden loading and unloading,coal loading and unloading, the coal handling plant, the exposedoverburden dump, the stock yard, the workshop, the exposed pit surface roadsand haul roads.Based on the study, a set of twelve emperical formulae have beendeveloped for calculation of suspended particulate matter (SPM)emission rates from various opencast coal mining activities. Theemission of gaseous pollutants (sulphur dioxide and nitrogenoxide) has been found negligible for various mining activities.Therefore, observation for gaseous pollutants has been consideredfor overall mine activities and empirical formulae have subsequently beendeveloped.The developed empirical formulae were calculatedby a field study at another coal mine. The measured andcalculated values of emission rate were compared for eachactivity. Average correlation between the measured andcalculated values for different activities was estimated to be 85.6–99.9%, which indicates fairly good accuracy.Validation of the study was also carried out by means of thefugitive dust model (FDM) using the calculated emissionrate data from the empirical formulae for each mining activity of amine, meteorological data and other details as input.The average accuracy between measured and predictedvalues of concentration of SPM at certain receptor locations wasfound to be 79%. A user-friendly emission software called`EmissCalc' was developed to calculate emission rate, whichcan be used as input for different air quality models.  相似文献   

Effectiveness of potassium in mitigating the salt-induced oxidative stress in contrasting tomato genotypes     

Muhammad Amjad  Javaid Akhtar  Muhammad Anwar-ul-Haq  Muhmmad Atif Riaz  Zulfiqar Ahmad Saqib  Behzad Murtaza 《Journal of plant nutrition》2016,39(13):1926-1935

To check the efficacy of potassium in alleviating oxidative stress under salt stress, salt-tolerant (Indent-1) and salt-sensitive (Red Ball) tomato (Lycopersicon esculentum Mill.) genotypes were exposed to three levels of sodium chloride (NaCl) (0, 75, 150 mM) and two levels of potassium (4.5 and 9 mM) in solution and foliar form. Thirty days of treatments revealed that increasing NaCl stress increased lipid peroxidation (malondialdehyde, MDA) and correspondingly the activity of antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT; and glutathione reductase GR) in both genotypes. However, higher potassium (K) level in solution or foliar spray during the salt-induced stress decreased MDA and antioxidant activity and increased the growth in salt-tolerant genotype than in the salt-sensitive genotype. Decrease in MDA concentration, activity of antioxidant enzymes, and increase in the growth of tomato plants by the application of potassium under salt stress suggest that potassium is an effective ameliorating agent against salt-induced oxidative damage.  相似文献   

Thiamine (vitamin B1) seed treatment enhances germination and seedling growth of bean (Phaseolus vulgaris L.) exposed to soaking injury     

Günter Neumann  Hassan Ahmad Azaizeh  Horst Marschner 《植物养料与土壤学杂志》1996,159(5):491-498

Seed treatment with thiamine mononitrate significantly increased germination rate of bean (Phasenius vulgaris L.) seedlings germinated at high soil moisture levels and low night-temperature (5° C). Beneficial effects of thiamine applications on germination were also observed in soil-free germination tests when the seeds were submerged in water for 1–4 d at 18°C. Optimum response was achieved at thiamine concentrations of 3 mM, applied during the first 24 h of imbibition. As an early response to the thiamine treatment, vital staining with triphenyltetrazolium chloride revealed a lower proportion of damaged tissue of the embryonic axes. In later stages of seedling development, thiamine seed treatment resulted in a lower proportion of abnormal seedlings with malformations of the shoot apex and of the primary leaves. The beneficial effect of thiamine was more pronounced when the temperature during submergence was kept at 25° C compared to 5° C. There was no response to thiamine applications when the germinating seeds were exposed to low temperature treatments only. The thiamine effect could be mimicked by raising the osmotic potential of the incubation medium, indicating a relationship to soaking injuries. The results suggest that normal seedling development may be impaired by thiamine deficiency in the embryonic tissue induced by soaking injury, whereas low temperatures are not involved as a stress-factor.  相似文献   

Elevated CO2 Improves Growth and Phosphorus Utilization Efficiency in Cereal Species Under Sub-Optimal Phosphorus Supply     

Renu Pandey  Krishna Kant Dubey  Altaf Ahmad  Rakshanda Nilofar  Rachana Verma  Vanita Jain 《Journal of plant nutrition》2015,38(8):1196-1217

Cultivars of Triticum aestivum, T. durum, and Secale cereale were grown at low (2 μM) and sufficient (500 μM) phosphorus (P) under ambient carbon dioxide (380 μmol mol^?1; aCO₂) and elevated CO₂ (700 μmol mol^?1, eCO₂) to study responses of cereal species in terms of growth and P utilization efficiency (PUE) under P x CO₂ interaction. Dry matter accumulation increased under eCO₂ with sufficient P. Nevertheless, dry matter accumulated at eCO₂ with low-P was similar to that obtained at aCO₂ with sufficient P. Leaf area was 43% higher under eCO₂ with sufficient P. Significant increase in lateral root density, length and surface area were noted at low-P under eCO₂. Phosphorus use efficience (PUE) increased by 59% in response to eCO_2­ in low-P plants. Thus, eCO₂ can partly compensate effect of low-P supply because of improved utilization efficiency. Among cereals, durum wheat was more suitable in terms of PUE under high CO₂ and limiting P supply.  相似文献   

Capillary column gas chromatographic determination of trace residues of the herbicide chlorsulfuron in agricultural runoff water   总被引：1，自引：0，他引：1  

I Ahmad 《Journal of the Association of Official Analytical Chemists》1987,70(4):745-748

A capillary column gas chromatographic method is described for determining parts-per-trillion (ppt) levels of chlorsulfuron in agricultural runoff water. The water sample is acidified with acetic acid and extracted with methylene chloride. The chlorsulfuron in the extracts derivatized to its monomethyl derivative. After Florisil column cleanup, the methylated chlorsulfuron is determined by electron-capture gas chromatography. Recovery of chlorsulfuron from fortified water samples is greater than 80%. Detection limit of the method is 25 ng chlorsulfuron/L water (25 ppt). There are 2 reaction sites on the chlorsulfuron molecule, both of which are susceptible to methylation leading to monomethyl chlorsulfuron and dimethyl chlorsulfuron. A procedure is described to methylate selectively the sulfonamide nitrogen of chlorsulfuron.  相似文献   

One-step extraction and cleanup procedure for determination of p,p'-DDT, p,p'-DDD, and p,p'-DDE in fish     

N Ahmad  R S Marolt 《Journal of the Association of Official Analytical Chemists》1986,69(4):581-586

A simplified method that combines extraction, partitioning, and cleanup in a single step for measuring p,p'-DDT and its metabolites in fish is described. Minced fish samples are emulsified with disodium hydrogen orthophosphate and trisodium citrate, ground with sodium sulfate, and eluted from a chromatographic column prepacked with alumina and silicic acid. The fats and fatty acids are solubilized and easily extracted from the tissues and retained by the column, while p,p'-DDT and its metabolites are quantitatively eluted with 40 mL n-hexane. The eluate is directly applied to a gas chromatographic column. Average recoveries of p,p'-DDT and its metabolites added to fish in vitro are 81%. The average coefficient of variation for recoveries of p,p'-DDT and its metabolites is less than 6.5% and the detection limit is 0.001 micrograms/g for p,p'-DDE, thus making this method very suitable for residue analysis.  相似文献   

Growth,survival, and heavy metal (Cd and Ni) uptake of spinach (Spinacia oleracea) and fenugreek (Trigonella corniculata) in a biochar‐amended sewage‐irrigated contaminated soil          下载免费PDF全文

Uzma Younis  Muhammad Farooq Qayyum  M. Hasnain Raza Shah  Subhan Danish  Ahmad Naeem Shahzad  Saeed Ahmad Malik  Seema Mahmood 《植物养料与土壤学杂志》2015,178(2):209-217

Irrigation of arable land with contaminated sewage waters leads to the accumulation of trace metals in soils with subsequent phyto‐/zootoxic consequences. In this study, biochar derived from cotton sticks was used to amend an agricultural silt‐loam soil that had been previously irrigated with trace metal contaminated sewage waters. Metal accumulation and toxicity to spinach (Spinacia oleracea) and fenugreek (Trigonella corniculata) was investigated by measuring concentrations of Cd and Ni in plant tissues and various photosynthetic and biochemical activities of plants. Positive impacts of biochar on both spinach and fenugreek were observed in terms of biomass production that increased from 29% to 36% in case of spinach, while for fenugreek this increase was 32% to 36%. In the control treatment there was an increase in malondialdihyde, soluble sugar, and ascorbic acid contents, indicating heavy metal stress. Biochar applications increased soluble proteins and amino acids in plants and reduced the uptake of Cd from 5.42 mg kg^?1 at control to 3.45 mg kg^?1 at 5% biochar amended soil and Ni (13.8 mg kg^?1 to 7.3 mg kg^?1 at 5% biochar) by the spinach plants. In fenugreek, the Cd was reduced from 7.72 mg kg^?1 to 3.88 mg kg^?1 and reduction in Ni was from 15.45 mg kg^?1 to 9.46 mg kg^?1 at 5% biochar treated soil, reducing the possibility of transfer up the food chain. This study demonstrates that the use of biochar made from cotton‐sticks, as an amendment to arable soils that have received contaminated irrigation water, could improve plant growth and decrease Cd and Ni uptake to crops, alleviating some of the negative impacts of using sewage waters on arable land.  相似文献   

Interrelationships between thirteen parameters of blood in apparently healthy buffalo-calves (Pakistan)     

M A Majeed  I R Khan  M A Toor  A Ahmad 《Revue d'élevage et de médecine vétérinaire des pays tropicaux》1986,39(3-4):409-414

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Evaluation of a modified-live virus vaccine administered in ovo to protect chickens against Newcastle disease.     

J Ahmad  J M Sharma 《American journal of veterinary research》1992,53(11):1999-2004

The B1 strain of Newcastle disease virus (NDV-B1), which is nonpathogenic for newly hatched chickens, killed embryos when it was used to inoculate chicken eggs at embryonation day 18. Treatment of NDV-B1 with an alkylating agent, ethylmethane sulfonate (EMS) markedly reduced the pathogenicity of the virus for 18-day-old chicken embryos. Eggs inoculated with the modified virus (NDV-B1-EMS) hatched, and the virus was isolated from lungs and spleen of 1-day-old chickens. The hatched chickens developed antibody to NDV and were protected against challenge exposure (at 4 weeks of age) with a highly virulent GB-Texas strain of NDV. Presence of maternal antibody to NDV in embryonating eggs did not influence the protective ability of NDV-B1-EMS, which also induced protective immunity when administered to 4-week-old chickens. The 50% protective dose of NDV-B1-EMS in maternal antibody-negative and -positive embryos was calculated to be 10.77 and 17.70 embryo 50% lethal doses, respectively. Results of the study indicated that NDV-B1-EMS may be used as an embryo vaccine to protect chickens against Newcastle disease.  相似文献