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1.
Sci Rep ; 13(1): 15193, 2023 Sep 14.
Article in English | MEDLINE | ID: mdl-37709862

ABSTRACT

Methane (CH4) is a greenhouse gas resulting from human activities, especially landfills, and it has many potential environmental issues, such as its major role in global warming. On the other hand, methane can be converted to liquid fuel or electricity using chemical conversion or gas turbine generators. Therefore, reusing such gases could be of great environmental and economic benefit. In this context, this study aims to estimate the emissions of methane gas from the landfills in Al-Hillah City, Iraq, from 2023 to 2070 and the producible electric energy from this amount. The estimating process was carried out using the Land GEM model and compared with traditional models. The obtained results demonstrated that the total estimated landfill methane emissions for 48 years are 875,217 tons, and the average annual methane emission is 18,234 tons based on a yearly waste accumulation rate of 1,046,413 tons and a total waste amount of 50,227,808 tons. The anticipated loads of methane gas can be utilized to generate about 287,442 MW/year of electricity from 2023 to 2070. In conclusion, the results obtained from this study could be evidence of the potential environmental and economic benefits of harvesting and reusing methane gas from landfills.

2.
Mymensingh Med J ; 28(4): 952-956, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31599268

ABSTRACT

Eventration of diaphragm is an abnormal elevation of diaphragmatic musculature while retaining normal attachments to the sternum, ribs and dorsolumber spine. It is a rare anomaly where the continuity of diaphragm remains intact. Pathological process can affect either all or only a portion of hemidiaphragm. Symptoms vary according to size of the defect. Large defect may mimic diaphragmatic hernia. The present case represents a full term female newborn that developed respiratory distress, cyanosis and feeding difficulties since 1st day of life. Clinical features and chest imaging of this case was assumed to be left sided diaphragmatic hernia which was found wrong in the operation theater. She was found to have left sided eventration of diaphragm to create symptom. Successful plication of ipsilateral diaphragm was done on 13th day of life. Supervised post operative ventilatory support along with other postoperative care improved the condition of this neonate. A large defect with eventration of diaphragm may be life threatening but a timely good management can save neonate from such condition.


Subject(s)
Diaphragmatic Eventration , Hernia, Diaphragmatic , Diaphragm , Female , Humans , Infant, Newborn , Postoperative Period
3.
Mymensingh Med J ; 28(2): 470-473, 2019 Apr.
Article in English | MEDLINE | ID: mdl-31086169

ABSTRACT

Organophosphorus compounds (OPC) are widely used insecticides. Such poisoning is very rare in neonate. A 23 days old infant was admitted with severe respiratory distress, excessive secretion from nose and mouth, bluish discoloration of extremities and poor feeding for 4 hours. He was pale, cyanosed and lethargic with gasping respiration. Frothing was coming through mouth and nose. There was watering of eyes, pupils were pin pointed and light reflex was sluggish. The baby was hypothermic, hypotonic with altered sensorium. Capillary refill time was <3 sec. The neonate was gasping; there was crepitation over lung fields. Precordium and abdomen was normal. An odor of OPC was smelt on clothing and secretions of the infant. The baby was wrapped with a cloth that was ware during pesticide spraying in the field. In addition to general measures, decontamination of skin and clothing and gastric lavage was done. Empirical antibiotic, injection atropine and pralidoxime were given. Patient showed clinical improvement with disappearance of cholinergic signs. The baby was discharged on 7th day of admission after full recovery.


Subject(s)
Antidotes/administration & dosage , Atropine/administration & dosage , Insecticides/poisoning , Organophosphate Poisoning/drug therapy , Organophosphorus Compounds/toxicity , Pralidoxime Compounds/administration & dosage , Antidotes/therapeutic use , Atropine/therapeutic use , Humans , Infant, Newborn , Male , Organophosphorus Compounds/adverse effects , Pralidoxime Compounds/therapeutic use , Treatment Outcome
4.
J Photochem Photobiol B ; 166: 202-211, 2017 Jan.
Article in English | MEDLINE | ID: mdl-27978500

ABSTRACT

The synthesis of silver nanoparticles (AgNPs) via green route, using biological entities is an area of interest, because one of the potential applications in the nanomedicine. In the present study, we have developed photo-induced, ecofriendly, low cost method for biosynthesis of the stable silver nanoparticles using aqueous extract of Dunaliella salina (AED) which act as both reducing as well as stabilizing agent. Biosynthesis of the AgNPs was optimized as: sunlight exposure (30min), AED (5% (v/v)) and AgNO3 (4mM). Biosynthesis of AgNPs was monitored by using UV-Vis spectroscopy which exhibited sharp SPR band at 430nm after 30min of bright sunlight exposure. SEM and TEM analyses confirmed the presence of spherical AgNPs with average size of 15.26nm. Crystalline nature of AgNPs was confirmed by SAED and XRD analyses where Braggs reflection pattern at (111), (200), (220) and (311) corresponded to face centered cubic crystal lattice of metallic silver. FTIR analysis revealed the involvement of various functional groups present in AED. AFM analysis confirmed the average surface roughness of synthesized AgNPs as 8.48nm. AgNPs were also screened for anticancer potential using assay of calcein AM/PI, Annexin/PI and cancer biomarkers against cancer cell line (MCF-7), while normal cell line (MCF-10A) were kept as control. Interestingly, anticancer potential was comparable to the known anticancer drug (Cisplatin), and was not detrimental to the normal cell line. Therefore, such green synthesized AgNPs may be explored as anticancer agent.


Subject(s)
Antineoplastic Agents, Phytogenic/pharmacology , Chlorophyta/metabolism , Metal Nanoparticles , Plant Extracts/pharmacology , Silver/chemistry , Biomarkers, Tumor/metabolism , Cell Line, Tumor , Humans , Microscopy, Electron, Transmission
5.
J Hazard Mater ; 181(1-3): 1134-42, 2010 Sep 15.
Article in English | MEDLINE | ID: mdl-20573445

ABSTRACT

Present study deals with the utilization of an agro-industrial waste wheat bran for the remediation of selenium species, Se(IV) and Se(VI) by continuous up-flow fixed-bed column system. Laboratory-scale column tests were performed to determine potentiality of wheat bran at various bed height, flow rates and initial metal ion concentration and it was found to be very potential biosorbent as it showed good sorption capacities of 72.54 microg/g and 62.51 microg/g for Se(IV) and Se(VI) respectively. Different models like Bed Depth Service Time (BDST), Thomas and Yoon-Nelson were applied to the experimental sorption data. The data showed very good fit to BDST model and sorption capacities (N(o)) computed using BDST model were 26,664 microg/L and 26,400 microg/L for Se(IV) and Se(VI) respectively. Also Yoon-Nelson model was found to show good agreement with the experimental kinetic results as compared to the Thomas model. Wheat bran was amenable to efficient regeneration with 10% NaOH. The biosorbent retained most of its original uptake capacity over three cycles of use. The excellent reusability of the biosorbent could lead to development of a viable metal remediation technology. Life factor calculation revealed that biosorbent bed will have sufficient capacity to avoid breakthrough at time t=0 up to 12.17 cycles for Se(IV) and 6.28 cycles for Se(VI) and bed would be completely exhausted after 56.89 cycles for Se(IV) and 18.73 cycles for Se(VI).


Subject(s)
Industrial Waste , Selenium/isolation & purification , Water Pollutants, Chemical/isolation & purification , Water Purification/methods , Adsorption , Biodegradation, Environmental , Dietary Fiber
6.
J Bone Joint Surg Br ; 92(6): 894-9, 2010 Jun.
Article in English | MEDLINE | ID: mdl-20513892

ABSTRACT

The nervous system is known to be involved in inflammation and repair. We aimed to determine the effect of physical activity on the healing of a muscle injury and to examine the pattern of innervation. Using a drop-ball technique, a contusion was produced in the gastrocnemius in 20 rats. In ten the limb was immobilised in a plaster cast and the remaining ten had mobilisation on a running wheel. The muscle and the corresponding dorsal-root ganglia were studied by histological and immunohistochemical methods. In the mobilisation group, there was a significant reduction in lymphocytes (p = 0.016), macrophages (p = 0.008) and myotubules (p = 0.008) between three and 21 days. The formation of myotubules and the density of nerve fibres was significantly higher (both p = 0.016) compared with those in the immobilisation group at three days, while the density of CGRP-positive fibres was significantly lower (p = 0.016) after 21 days. Mobilisation after contusional injury to the muscle resulted in early and increased formation of myotubules, early nerve regeneration and progressive reduction in inflammation, suggesting that it promoted a better healing response.


Subject(s)
Contusions/rehabilitation , Muscle, Skeletal/injuries , Nerve Regeneration/physiology , Wound Healing/physiology , Animals , Casts, Surgical , Contusions/pathology , Contusions/physiopathology , Disease Models, Animal , Early Ambulation , Female , Immobilization , Muscle, Skeletal/innervation , Muscle, Skeletal/pathology , Muscle, Skeletal/physiology , Rats , Rats, Sprague-Dawley
7.
J Hazard Mater ; 177(1-3): 312-22, 2010 May 15.
Article in English | MEDLINE | ID: mdl-20036460

ABSTRACT

Free and immobilized biomass of Aeromonas hydrophila has been utilized for the removal of Pb(II) from aqueous solution. Fitness of Langmuir sorption model to the sorption data indicated the sorption was monolayer and uptake capacity of biomass was 163.9 and 138.88 mg/g for the free and immobilized biomass respectively. 85.38% Pb(II) removal was achieved at bed height of 19 cm and flow rate of 2 mL/min and BDST model was in a good agreement with the experimental results (r(2)>0.997). An attempt has been made to optimize the process conditions for the maximum removal using Central Composite Design with the help of Minitab 15 software and the result predicted by optimization plots was 88.27% which is close to the experimental data i.e. 85.38%. Sorption-desorption studies revealed that polysulfone immobilized biomass could reused up to 16 cycles and bed was completely exhaust after 33 cycles.


Subject(s)
Aeromonas hydrophila/metabolism , Biodegradation, Environmental , Lead/isolation & purification , Water Pollutants, Chemical/isolation & purification , Adsorption , Aeromonas hydrophila/chemistry , Biomass , Equipment Design , Polymers , Software , Sulfones
8.
Bioresour Technol ; 100(19): 4462-7, 2009 Oct.
Article in English | MEDLINE | ID: mdl-19423339

ABSTRACT

Urease immobilized on alginate was utilized to detect and quantify As(3+) in aqueous solution. Urease from the seeds of pumpkin (vegetable waste) was purified to apparent homogeneity by heat treatment and gel filtration (Sephadex G-200). Further enzyme was entrapped in 3.5% alginate beads. Urea hydrolysis by enzyme revealed a clear dependence on the concentration and interaction time of As(3+). The process variables effecting the quantitation of As(3+) was investigated using central composite design with Minitab 15 software. The predicted results were found in good agreement (R(2)=96.71%) with experimental results indicating the applicability of proposed model. The multiple regression analysis and ANOVA showed that enzyme activity decreased with increase of As(3+) concentration and interaction time. 3D plot and contour plot between As(3+) concentration and interaction time was helpful to predict residual activity of enzyme for a particular As(3+) at a particular time.


Subject(s)
Alginates/chemistry , Arsenic/analysis , Cucurbita/enzymology , Environmental Restoration and Remediation/methods , Enzymes, Immobilized/metabolism , Urease/metabolism , Water/chemistry , Analysis of Variance , Glucuronic Acid/chemistry , Hexuronic Acids/chemistry , Ions , Regression Analysis , Solubility , Solutions , Substrate Specificity , Surface Properties , Time Factors
9.
J Hazard Mater ; 168(2-3): 1155-62, 2009 Sep 15.
Article in English | MEDLINE | ID: mdl-19345004

ABSTRACT

Biomass of Aeromonas hydrophila was successfully utilized for the removal of lead from aqueous solution. The effect of process variables such as pH, initial Pb(II) concentration, biomass dose and temperature on the uptake of lead were investigated using two level four factor (2(4)) full factorial central composite design with the help of MINITAB version 15 software. The predicted results thus obtained were found to be in good agreement (R(2)=98.6%) with the results obtained by performing experiments. The multiple regression analysis and analysis of variance (ANOVA) showed that the concentration has positive and temperature and biomass dose have negative whereas pH has curved relationship with the uptake of Pb(II). The maximum uptake of Pb(II) predicted by optimization plots was 122.18 mg/g at 20 degrees C, initial Pb(II) concentration of 259 mg/L, pH 5.0, temperature 20 degrees C and biomass dose 1.0 g. Langmuir isotherm model was applicable to sorption data and sorption capacity was found to be 163.3mg/g at 30 degrees C, pH 5.0 and Pb(II) concentration range 51.8-259 mg/L indicate that the biosorbent was better in comparison of the biosorbent reported in the literature. Dubinin-Radushkevich (D-R) isotherm model was also applied and it was found that sorption was chemisorption (E=12.98 kJ/mol). FT-IR studies indicate the involvement of various functional groups present on biomass surface in the sorption of Pb(II).


Subject(s)
Aeromonas hydrophila/metabolism , Biomass , Lead/metabolism , Water Pollutants, Chemical/metabolism , Analysis of Variance , Spectroscopy, Fourier Transform Infrared
10.
Appl Microbiol Biotechnol ; 83(3): 567-77, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19333592

ABSTRACT

In the present study, continuous up-flow fixed-bed column study was carried out using immobilized dead biomass of Aeromonas hydrophila for the removal of Cr(VI) from aqueous solution. Different polymeric matrices were used to immobilized biomass and polysulfone-immobilized biomass has shown to give maximum removal. The sorption capacity of immobilized biomass for the removal of Cr(VI) evaluating the breakthrough curves obtained at different flow rate and bed height. A maximum of 78.58% Cr(VI) removal was obtained at bed height of 19 cm and flow rate of 2 mL/min. Bed depth service time model provides a good description of experimental results with high correlation coefficient (> 0.996). An attempt has been made to investigate the individual as well as cumulative effect of the process variables and to optimize the process conditions for the maximum removal of chromium from water by two-level two-factor full-factorial central composite design with the help of Minitab version 15 statistical software. The predicted results are having a good agreement (R (2) = 98.19%) with the result obtained. Sorption-desorption studies revealed that polysulfone-immobilized biomass could be reused up to 11 cycles and bed was completely exhausted after 28 cycles.


Subject(s)
Aeromonas hydrophila/metabolism , Chromium/chemistry , Water Pollutants, Chemical/chemistry , Water Purification/methods , Aeromonas hydrophila/chemistry , Biodegradation, Environmental , Chromium/metabolism , Kinetics , Water Pollutants, Chemical/metabolism
11.
J Hazard Mater ; 166(2-3): 1050-9, 2009 Jul 30.
Article in English | MEDLINE | ID: mdl-19131161

ABSTRACT

'Rice polish' (an agricultural residue) was utilized successfully for the removal of arsenic from aqueous solution. Various parameters viz. pH, biosorbent dosage, initial metal ion concentration and temperature were studied. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models were used and the system followed all three isotherms, showing sorption to be monolayer on the heterogeneous surface of the biosorbent. The maximum sorption capacity calculated using Langmuir model was 138.88 microg/g for As(III) at 20 degrees C and pH 7.0 and 147.05 microg/g at 20 degrees C and pH 4.0 for As(V). The mean sorption energy (E) calculated from D-R model indicated chemisorption nature of sorption. Study of thermodynamic parameters revealed the exothermic, spontaneous and feasible nature of sorption process in case of both As(III) and As(V). The pseudo-second-order rate equation described better the kinetics of arsenic sorption with good correlation coefficients than pseudo-first-order equation. Mass transfer, intraparticle diffusion, richenberg and elovich models were applied to the data and it was found that initially the sorption of arsenic was governed by film diffusion followed by intraparticle diffusion. Rice polish was found to be efficient in removing arsenic from aqueous solution as compared to other biosorbents already used for the removal of arsenic.


Subject(s)
Arsenic/isolation & purification , Oryza , Water Pollutants, Chemical/isolation & purification , Adsorption , Diffusion , Hydrogen-Ion Concentration , Kinetics , Solutions , Temperature , Thermodynamics , Water Purification/methods
12.
Cytopathology ; 20(4): 231-4, 2009 Aug.
Article in English | MEDLINE | ID: mdl-18627403

ABSTRACT

OBJECTIVE: To assess the diagnostic value of clot examination for satisfactory processing and confirmation of malignancy in serous effusions in routine cytological evaluation and compare the results with those of conventional smear and cell block preparations. METHODOLOGY: Body cavity fluids (n = 600) received in our laboratory were processed according to a pre-designed protocol for the study as follows: Day1: on receipt of the specimen, smears were made and a cell block was prepared from the sediment. Day2: after overnight sample storage of the remaining specimen at 2-8 degrees C all fluids were examined for the presence of a clot at the bottom of the container. Fluids in which clot had formed were fixed in formalin. The clot was then placed on a lens paper, wrapped and processed routinely. Diagnostic yields were compared. RESULTS: In this study, we included 600 cases of serous fluids from pleural, pericardial and peritoneal effusions. In 73% (n = 437) of samples, clot formation was seen, while in 27%, (n = 163) no clot had formed. Routine smear and cell block preparations showed malignant cells in 9.6% (n = 42). However, with the addition of the clot preparation, the number of cases in which atypical/malignant cells were seen increased from 42 to 85 (19.4%), with a P < 0.001. Special stains and immunohistochemistry (IHC) were also performed on clot preparations in 10 difficult cases. CONCLUSION: Clot preparation from body cavity fluids on the second day can be used as an adjunct to smear and routine cell block preparation to improve the accuracy and yield of the cytological diagnosis and may also be of great help for special studies such as IHC staining.


Subject(s)
Ascitic Fluid/pathology , Body Fluids/cytology , Neoplasms/diagnosis , Pericardial Effusion/pathology , Pleural Effusion, Malignant/pathology , Specimen Handling/methods , Blood Coagulation , Female , Humans , Male , Neoplasms/pathology , Sensitivity and Specificity
13.
Appl Biochem Biotechnol ; 158(3): 524-39, 2009 Sep.
Article in English | MEDLINE | ID: mdl-19031053

ABSTRACT

The potential use of biomass of Aeromonas hydrophila for biosorption of chromium from aqueous solution was investigated. The variables (pH, initial Cr(VI) concentration, biomass dose, and temperature) affecting process were optimized by performing minimum number of experimental runs with the help of central composite design. The results predicted by design were found to be in good agreement (R2 = 99.1%) with those obtained by performing experiments. Multiple regression analysis shows that uptake decreases with increase in pH and biomass dose, whereas it increases with increase in temperature and concentration. The maximum removal of Cr(VI) predicted by contour and optimization plots was 184.943 mg/g at pH 1.5, initial Cr(VI) concentration 311.97 mg/L, temperature 60 degrees C, and biomass dose 1.0 g. The removal of Cr(VI) was governed by adsorption of Cr(VI) as well as its reduction into Cr(III), which further gets adsorbed. The sorption capacity of biomass was calculated from experimental data using Langmuir sorption model and was found to be 151.50 mg/g at 40 degrees C and pH 1.5, which is comparable to other biosorbents. In addition to this, Dubinin-Radushkevich model was applied, and it was found that nature of sorption was chemisorption.


Subject(s)
Aeromonas hydrophila/metabolism , Chromium/isolation & purification , Chromium/metabolism , Water Pollutants, Chemical/isolation & purification , Water Pollutants, Chemical/metabolism , Water Purification/methods , Adsorption , Biomass , Chromium/chemistry , Hydrogen-Ion Concentration , Regression Analysis , Water Pollutants, Chemical/chemistry
14.
Bioresour Technol ; 99(16): 7565-72, 2008 Nov.
Article in English | MEDLINE | ID: mdl-18378444

ABSTRACT

Free as well as alginate immobilized urease was utilized for detection and quantitation of cadmium (Cd2+) in aqueous samples. Urease from the seeds of pumpkin (Cucumis melo), being a vegetable waste, was extracted and purified to apparent homogeneity (Sp. Activity 353 U/mg protein; A280/A260=1.12) by heat treatment at 48+/-0.1 degrees C and gel filtration through Sephadex G-200. The homogeneous enzyme preparation was immobilized in 3.5% alginate leading to 86% immobilization and no leaching of the enzyme was found over a period of 15 days at 4 degrees C. Urease catalyzed urea hydrolysis by both soluble and immobilized enzyme revealed a clear dependence on the concentration of Cd2+. The inhibition caused by Cd2+ was non-competitive (Ki=1.41 x 10(-5) M). The time dependent inhibition both in the presence and in absence of Cd2+ ion revealed a biphasic inhibition in the activity. A Response Surface Methodology (RSM) for the parametric optimization of this process was performed using two-level-two-full factorial (2(2)), central composite design (CCD). The regression coefficient, regression equation and analysis of variance (ANOVA) was obtained using MINITAB 15 software. The predicted values thus obtained were closed to the experimental value indicating suitability of the model. In addition to this 3D response surface plot and isoresponse contour plot were helpful to predict the results by performing only limited set of experiments.


Subject(s)
Cadmium/analysis , Research Design , Urease/chemistry , Vegetables/chemistry , Water/chemistry , Alginates/chemistry , Cadmium/chemistry , Cucumis/enzymology , Data Interpretation, Statistical , Enzymes, Immobilized , Factor Analysis, Statistical , Hydrolysis , Kinetics , Seeds/enzymology , Solubility , Solutions , Surface Properties , Temperature , Time Factors , Urea/metabolism , Urease/antagonists & inhibitors
15.
J Hazard Mater ; 152(1): 356-65, 2008 Mar 21.
Article in English | MEDLINE | ID: mdl-17706866

ABSTRACT

Novel biosorbent 'maize bran' has been successfully utilized for the removal of Cr(VI) from aqueous solution. The effect of different parameters such as contact time, sorbate concentration, pH of the medium and temperature were investigated and maximum uptake of Cr(VI) was 312.52 (mgg(-1)) at pH 2.0, initial Cr(VI) concentration of 200mgL(-1) and temperature of 40 degrees C. Effect of pH showed that maize bran was not only removing Cr(VI) from aqueous solution but also reducing toxic Cr(VI) into less toxic Cr(III). The sorption kinetics was tested with first order reversible, pseudo-first order and pseudo-second order reaction and it was found that Cr(VI) uptake process followed the pseudo-second order rate expression. Mass transfer of Cr(VI) from bulk to the solid phase (maize bran) was studied at different temperatures. Different thermodynamic parameters, viz., DeltaG degrees , DeltaH degrees and DeltaS degrees have also been evaluated and it has been found that the sorption was feasible, spontaneous and endothermic in nature. The Langmuir and Freundlich equations for describing sorption equilibrium were applied and it was found that the process was well described by Langmuir isotherm. Desorption studies was also carried out and found that complete desorption of Cr(VI) took place at pH of 9.5.


Subject(s)
Agriculture , Chromium/isolation & purification , Industrial Waste , Zea mays , Diffusion , Hydrogen-Ion Concentration , Kinetics , Solutions , Thermodynamics , Water/chemistry
16.
Bioresour Technol ; 98(4): 918-28, 2007 Mar.
Article in English | MEDLINE | ID: mdl-16678404

ABSTRACT

The water hyacinth (Eichchornia crassipes) has been successfully utilized for the removal of Zn(II) and Cd(II) as well as their admixture from samples of aqueous solutions. The growth of the plant after 16 days of exposure to the metal ions showed an increasing trend up to 2.5 ppm of Cd(II) and 6.0 ppm of Zn(II) concentrations, however, the growth became nondetectable or inhibited above these concentrations. The overall metal uptake by the plant was dependent upon the concentration of the metal and the duration of the exposure time. The metal uptake from a mixture of Cd(II) and Zn(II) was reflected by a rate constant quite different from those solutions containing only one metal ion. An analysis of metal in roots and tops of the plants showed that more Zn(II) was accumulated in the root when compared to Cd(II). However, the accumulation factor for the tops and the roots for Cd(II) and Zn(II) was higher than those obtained admixture of Zn(II) and Cd(II). The rate of metal mobility in the root was slower than that in the top of the plant for Zn(II) and Cd(II). A water hyacinth based system can be used to remove Cd(II) and Zn(II) from water/wastewater.


Subject(s)
Cadmium/chemistry , Eichhornia/chemistry , Zinc/chemistry , Adsorption , Eichhornia/growth & development , Kinetics , Solutions , Water
17.
Bioresour Technol ; 97(8): 994-1001, 2006 May.
Article in English | MEDLINE | ID: mdl-15993581

ABSTRACT

Novel bio-sorbent wheat bran has been successfully utilized for the removal of cadmium(II) from wastewater. The maximum removal of cadmium(II) was found to be 87.15% at pH 8.6, initial Cd(II) concentration of 12.5 mg l-1 and temperature of 20 degrees C. The effect of different parameters such as contact time, adsorbate concentration, pH of the medium and temperature were investigated. Dynamics of the sorption process were studied and the values of rate constant of adsorption, rate constant of intraparticle diffusion and mass transfer coefficient were calculated. Different thermodynamic parameters viz., changes in standard free energy, enthalpy and entropy have also been evaluated and it has been found that the reaction was spontaneous and exothermic in nature. The applicability of Langmuir isotherm showed of monolayer coverage of the adsorbate on the surface of adsorbent. A generalized empirical model was proposed for the kinetics at different initial concentrations.


Subject(s)
Cadmium/isolation & purification , Triticum/chemistry , Waste Disposal, Fluid/methods , Water Pollutants, Chemical/isolation & purification , Water Pollution, Chemical/prevention & control , Adsorption , Dietary Fiber , Hydrogen-Ion Concentration , Kinetics , Spectrophotometry, Infrared , Temperature , Thermodynamics , X-Ray Diffraction
18.
Bioresour Technol ; 97(16): 2124-30, 2006 Nov.
Article in English | MEDLINE | ID: mdl-16275062

ABSTRACT

Maize bran is a low cost biosorbent that has been used for the removal of lead(II) from an aqueous solution. The effects of various parameters such as contact time, adsorbate concentration, pH of the medium and temperature were examined. Optimum removal at 20 degrees C was found to be 98.4% at pH 6.5, with an initial Pb(II) concentration of 100 mg l(-1). Dynamics of the sorption process and mass transfer of Pb(II) to maize bran were investigated and the values of rate constant of adsorption, rate constant of intraparticle diffusion and the mass transfer coefficients were calculated. Different thermodynamic parameters viz., changes in standard free energy, enthalpy and entropy were evaluated and it was found that the reaction was spontaneous and exothermic in nature. The adsorption data fitted the Langmuir isotherm. A generalized empirical model was proposed for the kinetics at different initial concentrations. The data were subjected to multiple regression analysis and a model was developed to predict the removal of Pb(II) from an aqueous solution.


Subject(s)
Lead/isolation & purification , Water Pollutants, Chemical/analysis , Water Purification/methods , Zea mays/chemistry , Adsorption , Agriculture , Hydrogen-Ion Concentration , Kinetics , Lead/analysis , Models, Chemical , Temperature , Thermodynamics , Waste Products
19.
J Colloid Interface Sci ; 290(1): 61-8, 2005 Oct 01.
Article in English | MEDLINE | ID: mdl-16122543

ABSTRACT

The novel biosorbent rice bran has been successfully utilized for the removal of Cr(VI) from wastewater. The maximum removal of Cr(VI) was found to be 99.4% at pH 2.0, initial Cr(VI) concentration of 200 mg l(-1), and temperature 20 degrees C. The effect of different parameters such as contact time, adsorbate concentration, pH of the medium, and temperature was investigated. The adsorption kinetics was tested for first-order reversible, pseudo-first-order, and pseudo-second-order; reaction and the rate constants of kinetic models were calculated. Mass transfer of Cr(VI) from the bulk to the solid phase (rice bran) was studied at different temperatures. Different thermodynamic parameters, viz., changes in standard free energy, enthalpy, and entropy, have also been evaluated and it has been found that the reaction was spontaneous and endothermic in nature. The Langmuir and Freundlich equations for describing adsorption equilibrium were applied to data. The constants and correlation coefficients of these isotherm models were calculated and compared. Desorption studies was also carried out and found that complete desorption of Cr(VI) took place at pH of 9.5. The data were also subjected to multiple regression analysis and a model was developed to predict the removal of Cr(VI) from wastewater.


Subject(s)
Chromium/chemistry , Oryza/chemistry , Water Pollutants, Chemical , Water Purification/methods , Adsorption , Hydrogen-Ion Concentration , Regression Analysis , Sensitivity and Specificity , Surface Properties , Temperature , Thermodynamics , Water Purification/instrumentation
20.
J Hazard Mater ; 121(1-3): 51-8, 2005 May 20.
Article in English | MEDLINE | ID: mdl-15885406

ABSTRACT

A novel biosorbent rice polish has been successfully utilized for the removal of cadmium(II) from wastewater. The maximum removal of cadmium(II) was found to be 9.72 mg g(-1) at pH 8.6, initial Cd(II) concentration of 125 mg l(-1) and temperature of 20 degrees C. The effect of different parameters such as contact time, adsorbate concentration, pH of the medium and temperature were investigated. Dynamics of the sorption process were studied and the values of rate constant of adsorption, rate constant of intraparticle diffusion and mass transfer coefficient were calculated. Different thermodynamic parameters, viz., changes in standard free energy, enthalpy and entropy have also been evaluated and it has been found that the reaction was spontaneous and exothermic in nature. The applicability of Langmuir isotherm showed monolayer coverage of the adsorbate on the surface of adsorbents. A generalised empirical model was proposed for the kinetics at different initial concentrations. The data were subjected to multiple regression analysis and a model was developed to predict the removal of Cd(II) from wastewater.


Subject(s)
Agrochemicals/isolation & purification , Cadmium/chemistry , Waste Disposal, Fluid/instrumentation , Waste Disposal, Fluid/methods , Water Pollutants, Chemical/isolation & purification , Water Pollution, Chemical/prevention & control , Adsorption , Hydrogen-Ion Concentration , Models, Chemical , Regression Analysis , Temperature
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