Shaheed Ziaur Rahman Medical College

Bogra, Bangladesh

Shaheed Ziaur Rahman Medical College

Bogra, Bangladesh
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Awual M.R.,Japan Atomic Energy Agency | Hasan M.M.,Shaheed Ziaur Rahman Medical College | Khaleque M.A.,Independent University, Bangladesh | Sheikh M.C.,University of Toyama
Chemical Engineering Journal | Year: 2016

A sensitive and selective colorimetric method for simultaneous detection and removal of copper (Cu(II)) ion from contaminated water samples was developed based on the functional ligand embedded mesoporous conjugate materials. The synthesized material's characterization was also presented. The conjugate materials exhibited an obvious color change from colorless to dark yellow in the presence of Cu(II) ion according to the pH values. Also, the Cu(II) ion were detected and removed through naked-eye. The prepared material exhibited significant color change upon addition of Cu(II) ion even in the presence of other competing ions, and the limit of detection was calculated to be 0.15. μg/L. Excellent selectivity toward Cu(II) ion was observed due to a specific complex formation between Cu(II) ion and organic ligand of the conjugate materials. In Cu(II) adsorption operation, several affecting factors, including the solution pH, contact time, initial Cu(II) ion concentration, foreign ions and reuses were investigated. The results showed that the conjugate materials exhibited excellent adsorption capacity and adsorption equilibrium was reached rapidly. The adsorption results were well fitted with Langmuir adsorption isotherms and the maximum adsorption capacity by the materials for Cu(II) ion was 174.76. mg/g. We claimed from this study that Cu(II) could be successfully detected and removed by the adsorption method developed in the current work. The present work is obviously much simpler and greener than the conventional comprising multistep processes. The results demonstrated that Cu(II) ion loaded conjugate materials was effectively regenerated using HCl acid solution, and the regenerated materials was repeated to use many cycles without significant capacity loss, indicating the good stability of prepared conjugate materials. © 2015 Elsevier B.V.


Awual M.R.,Japan Atomic Energy Agency | Hasan M.M.,Shaheed Ziaur Rahman Medical College | Khaleque M.A.,Independent University, Bangladesh
Sensors and Actuators, B: Chemical | Year: 2015

Selenium occurs naturally in the environment and is toxic at elevated concentrations, which has been a challenging issue for environmental scientists. This work was devoted to the detection and removal the selenium (Se(IV)) from aqueous solutions using organic ligand an immobilized conjugate adsorbent. The organic ligand of (3-(3-(methoxycarbonyl) benzylidene)hydrazinyl) benzoic acid was synthesized and indirectly immobilized onto the mesoporous silica. The adsorbent was applied to detect and remove Se(IV) in aqueous solutions at optimum conditions. This adsorbent exhibited high surface area-to-volume ratios and pores were uniform nanostructures. The adsorbent permitted rapid Se(IV) capturing detectable by naked eye observation. The limit of detection was 2.02 μg/L by the proposed method of the conjugate adsorbent. The Se(IV) capture system was optimized by varying the parameters of contact time, pH, initial concentration, competing ions and elution operations. The pH effect played an important role and the solution pH ranging from 0.5 to 7.0 was investigated. The data confirmed that acidic pH enhanced the Se(IV) sorption on the conjugate adsorbent resulting in an increased sorption efficiency percentage of Se(IV) to >98% at pH 1.50. The data were also fitted to the Langmuir isotherm, and the maximum sorption capacity was 93.56 mg/g. The introduction of diverse ions was individually added to solution, and these had no significant effect on the Se(IV) sorption by the adsorbent. The 0.20 M NaOH was used an eluent in the elution operation, and the adsorbent was used in many cycles without loss of cage cavities. Therefore, the conjugate adsorbent has shown favorable capturing ability in water samples, and this could be used as efficient adsorbents in potential practical applications for Se(IV) detection and removal from wastewater. © 2014 Elsevier B.V. All rights reserved.


Awual M.R.,Japan Atomic Energy Agency | Hasan M.M.,Shaheed Ziaur Rahman Medical College | Naushad M.,King Saud University | Shiwaku H.,Japan Atomic Energy Agency | Yaita T.,Japan Atomic Energy Agency
Sensors and Actuators, B: Chemical | Year: 2015

This study demonstrated the composite adsorbent preparation by ligand of 5-tert-butyl-2-hydroxybenzaldehyde thiosemicarbazone immobilized onto mesoporous silica for efficient palladium (Pd(II)) detection, separation and recovery. The composite adsorbent enhanced the color formation upon the addition of different concentrations of Pd(II) based on the stable complex formation tendency by charge transfer (π-π transition) mechanism. The influence of different parameters such as solution pH, initial Pd(II) concentration, equilibration time, presence of diverse ions and reuses were evaluated and discussed systematically. The effective pH range for Pd(II) ions detection and sorption was at 3.50 and limit of detection was 0.13 μg/L. This procedure allows the simultaneous determination and recovery of Pd(II) in synthetic samples consisting of diverse ions. The adsorption isotherm data were well fitted with the Langmuir model, and the maximum sorption capacity of the composite adsorbent was 171.65 mg/g, which was close to the equilibrium sorption capacity. The adsorbed Pd(II) was effectively extracted/eluted using acidic thiourea. The composite adsorbent retained functionality in spite of many chemical treatments during sorption-elution-recovery/regeneration cycles and the adsorbent could be used several cycles without significant deterioration in its original performances. The Pd(II) detection and sorption were also measured with simulated environmental solution, and the data confirmed the high selectivity to Pd(II), thus the composite adsorbent showing the potentiality for possible use in efficient detection, separation and recovery of Pd(II) from waste samples. © 2014 Elsevier B.V. All rights reserved.


Awual M.R.,Japan Atomic Energy Agency | Hasan M.M.,Shaheed Ziaur Rahman Medical College
Sensors and Actuators, B: Chemical | Year: 2015

The nitrogen donor ligand was functionalized with polarable mesoporous silica as composite adsorbent, by a cost-effective and environmentally friendly procedure, for highly selective copper (Cu(II)) ions detection and removal from water. The nitrogen donor ligand of N,N(octane-1,8-diylidene)di(2-hydroxy-3,5-dimethylaniline) was synthesized to be specific to Cu(II) ions. The composite adsorbent permitted fast and specific Cu(II) ions capturing via colorimetric naked-eye detection based on stable complexation [Cu(II)-ligand]n+ mechanism. The effect of pH value, interferential metal ions, initial Cu(II) concentration, and contact time on adsorption capability were investigated systematically. The adsorbent was selective toward Cu(II) as shown by a light yellow to green color change. This was characterized by UV-vis spectroscopy and the color change was observed for the visual detection of Cu(II) ions. The ions selectivity of the adsorbent toward Cu(II) was determined by changes in UV-vis reflectance spectra. However, the presence of competing ions showed no interference for the detection of Cu(II) ion by the composite adsorbent. The results demonstrated that the composite adsorbent exhibited excellent sorption performance for Cu(II) ions. The low detection limit and sorption capacity of the adsorbent were 0.10 μg/L and 200.80 mg/g, respectively. The adsorbed Cu(II) was eluted with suitable eluent and simultaneously regenerated into the initial form for next operation without significant deterioration in its nanostructure case cavities. The data also confirmed that the adsorbent is a cost-effective and environmentally friendly procedure for Cu(II) treatment. Therefore, the composite adsorbent can be considered as a potential adsorbent for Cu(II) ions monitoring and removal from wastewater. © 2014 Elsevier B.V. All rights reserved.


Rabiul Awual M.,Japan Atomic Energy Agency | Munjur Hasan M.,Shaheed Ziaur Rahman Medical College | Ihara T.,Kumamoto University | Yaita T.,Japan Atomic Energy Agency
Microporous and Mesoporous Materials | Year: 2014

Selenium is a very toxic element that at low concentration can affect human beings and living organisms. In this study, the ligand immobilized conjugate adsorbent was developed and selenium (Se(IV)) detection and removal from water were investigated. The conjugate adsorbent was successfully prepared by direct immobilization of 6-((2-(2-hydroxy-1 naphthoyl)hydrazono) methyl)benzoic acid onto mesoporous inorganic silica. This study was performed to evaluate the several influencing parameters such as solution pH, contact time, initial concentration, and the presence of competitive ions on the monitoring and removal performance. The adsorbent has the specific functionality for Se(IV) detection and removal from aqueous media. Moreover, the adsorbent has large surface area-to-volume ratios and uniformly mesostructures shaped pores that were actively working to capture Se(IV). The point of zero charge of the adsorbent was evaluated to understand the adsorption phenomenon. The limit of detection of the method presented was 2.16 ppb at optimum conditions. The adsorption data were well interpreted by the Langmuir adsorption isotherm and the maximum adsorption capacity was 103.73 mg/g. The adsorbent was capable of Se(IV) removal even in the presence of a high amount of coexisting cations and anions such as sodium, potassium, calcium, chloride, nitrate, sulfate, phosphate and etc. This technique achieved residual Se(IV) concentration less than 10 ppb, which is acceptable by water quality regulations. The adsorbed Se(IV) was eluted with 0.10 M NaOH and simultaneously regenerated into the initial form for the next operation after rinsing with water. Moreover, the adsorbent was retaining functionality in spite of several cycles during sorption-elution- regeneration operations. Therefore, the solid design adsorbent is efficient and cost-effective for selective Se(IV) detection and removal from water. © 2014 Elsevier Inc. All rights reserved.


Awual M.R.,Japan Atomic Energy Agency | Hasan M.M.,Shaheed Ziaur Rahman Medical College
Microporous and Mesoporous Materials | Year: 2014

Lead (Pb(II)) is a very toxic heavy metal that even at low concentration can affect living organisms. Therefore, designing effective materials with high selectivity and cost-effeciency is essential for the control capturing of toxic Pb(II) ions. This study developed a ligand based conjugate adsorbent for simultaneous Pb(II) detection and removal from water samples. The organic ligand of 4-dodecyl-6-((4-(hexyloxy)phenyl)diazenyl) benzene-1,3-diol (DPDB) was synthesized and DPDB was successfully immobilized onto mesoporous silica by a direct immobilization approach. The Pb(II) ion was detected by the charge transfer (π-π transition) transduction mechanism with sensitivity and selectivity. The experiment conditions were optimized based on contact time, solution acidity, initial Pb(II) concentration and pH value and diverse metal salt concentrations. The adsorbent was highly sensitive, and the limit of detection was 0.18 μg/L for Pb(II) ions. The Pb(II) sorption synthetic aqueous solution also underwent batch tests. However, the sorption capacity depended on the solutions pH, initial concentration and to some extent on the competing ions. The experimental data revealed that the maximum Pb(II) sorption was possible at pH 5.0. The presence of other cations and anions did not adversely affect the Pb(II) capturing by the adsorbent. The maximum sorption capacity was determined to be as high as 195.31 mg/g. The extraction of Pb(II) ions from the saturated adsorbent was possible with 0.20 M HCl. The regenerated adsorbent that remained maintained the high selectivity to Pb(II) ions and exhibited almost the same sorption capacity as that of the original adsorbent. However, the sorption efficiency slightly decreased after ten cycles. Therefore, the proposed adsorbent offered a cost-effective material and may be considered a viable alternative for effectively monitoring and removing toxic Pb(II) ions from water samples without the need for sophisticated instrument. © 2014 Elsevier Inc. All rights reserved.


Awual M.R.,Japan Atomic Energy Agency | Hasan M.M.,Shaheed Ziaur Rahman Medical College
Sensors and Actuators, B: Chemical | Year: 2014

The functionalized mesoporous silica based fine-tuning mesoporous adsorbent was developed for ultra-trace lead (Pb(II)) detection and removal from wastewater. The mesoporous adsorbent was fabricated by direct immobilization of 1E,1'E,1"E,1"'E(tetrakis(3-carboxysalicylidene)) naphthalene-1,2,5,5- tetramine (TSNT) onto mesoporous silica monoliths. The design of the ligand into ordered pore-based mesoporous adsorbent transformed the Pb(II) detection and removal systems into smart and stable assemblies. The ability of the mesoporous adsorbent to detect and remove Pb(II) from aqueous solutions has been studied and discussed with different optimized conditions of concentrations, the amount of mesoporous adsorbent, concentration of coexisting electrolyte and pH. The design of such a tunable mesoporous adsorbent offered a simple procedure in such toxic Pb(II) ions removal without using high-tech, sophisticated instruments. The mesoporous adsorbent was able to detect the ultra-trace Pb(II) ions with high sensitivity and selectivity based on charge transfer ((intense π-π transition) transduction. Therefore, the mesoporous adsorbent proved to have an efficient ability for continuous monitoring of toxic Pb(II) ions even on-site and in situ chemical analyses. The removal data revealed that mesoporous adsorbent has high sorption capacity (184.32 mg/g) based on sorption isotherms measurements. The major advantage of the tunable design mesoporous adsorbent was that the mesoporous adsorbent retained highly efficient sensitive selectivity without a significant kinetic hindrance, despite the slight decrease of sorption after several regeneration/reuse cycles. Uptake of Pb(II) onto mesoporous adsorbent to equilibrium occurred quickly and the mesoporous adsorbent could be regenerated for reuse with diluted HCl. Therefore, the mesoporous adsorbent has been shown to have the potential to be used as an effective adsorbent for ultra-trace Pb(II) ions detection and removal from wastewater. © 2014 Elsevier B.V.


Awual Md.R.,Japan Atomic Energy Agency | Hasan Md.M.,Shaheed Ziaur Rahman Medical College | Shahat A.,Suez Canal University
Sensors and Actuators, B: Chemical | Year: 2014

An efficient material is needed to develop selective and effective sensing/removal systems with high flexibility, and low capital cost for control the capturing of toxic ions. In this study, we designed ligand immobilized mesoporous adsorbent for ultra-trace Pb(II) monitoring and removal from wastewater. The adsorbent was synthesized by indirect immobilization of 4-tert-octyl-4-((phenyl)diazenyl)phenol onto inorganic mesoporous silica. This adsorbent exhibited the large surface area-to-volume ratios and uniformly shaped pores in case cavities, and its active sites kept open functionality to taking up Pb(II). The applicability of the adsorbent for Pb(II) detection and removal was assessed, and the efficient parameters such as solution pH, contacting time, initial Pb(II) concentration and ionic strength of competing ions were measured. The effective pH range for detection and removal systems was at the neutral region. The data revealed that the adsorbent was able to detect the ultra-trace Pb(II) ions with high sensitivity and selectivity by charge transfer (intense π-π transition) transduction mechanism. Then the adsorbent proved to have an efficient ability for continuous Pb(II) monitoring and removal even on-site and in situ chemical analyses. The maximum sorption capacity and limit of detection were 200.80 mg/g and 0.12 μg/L, respectively. The adsorbent was reused in several cycles without significant deterioration after elution with a suitable eluent (0.10 M HCl). Therefore, the design of mesoporous adsorbent has a great potentiality to be used in selective Pb(II) detection/removal from wastewater. Large-scale studies are recommended to confirm these promising results from the laboratory scale. © 2014 Elsevier B.V. All rights reserved.


Awual M.R.,Japan Atomic Energy Agency | Hasan M.M.,Shaheed Ziaur Rahman Medical College | Znad H.,Curtin University Australia
Chemical Engineering Journal | Year: 2015

The functional group containing organic ligand of N,. N(octane-1,8-diylidene)di(2-hydroxy-3,5-dimethylaniline) (DHDM) was developed and then successfully anchored onto mesoporous silica for the preparation of nano-conjugate adsorbent (NCA). After fabrication, the DHDM kept open functionality for capturing palladium (Pd(II)) under optimum conditions. The NCA exhibited the distinct color formation (π-π transition) after adding the Pd(II) ions both in solid and liquid states. The solution pH played an important role in the detection and sorption of Pd(II) but the prepared NCA worked well in the acidic pH region at 1.50. The data also clarified that the NCA did not form any color and signal intensity even in the presence of diverse ions except Pd(II). The determined limit of detection to Pd(II) ions was low as 0.14. μg/L. In Pd(II) sorption, the affecting factors such as solution pH, kinetics, isotherm models, competing ions and elution/regeneration were studied in detail. The NCA confirmed the rapid sorption property and the maximum sorption capacity was 213.67. mg/g due to spherical nanosized cavities with large surface area and pore volume. The base metal of Cu(II) and Zn(II) did not hamper the Pd(II) sorption ability of NCA in the acidic pH region. Therefore, it was expected that the Pd(II) could be separated from other hard metal ions by the NCA. The data also clarified that the other competing metal ions did not decrease the Pd(II) sorption capacity and NCA had almost no sorption capacity, which suggested the high selectivity of Pd(II) ions by NCA. The adsorbed Pd(II) was eluted with 0.20. M HCl-0.20. M thiourea eluent and simultaneously regenerated into the original form. The NCA was reversible and kept remaining functionality for reuse in many cycles after an extraction/elution process without significant deterioration. Therefore the proposed NCA can be considered as a potential candidate for Pd(II) capturing from waste samples. © 2014 Elsevier B.V.


Awual M.R.,Japan Atomic Energy Agency | Hasan M.M.,Shaheed Ziaur Rahman Medical College
Journal of Industrial and Engineering Chemistry | Year: 2015

A simple and sensitive method was applied for determination and extraction of trace level palladium(II) in wastewater by using functionalized mesoporous silica based fine-tuning mesoporous adsorbent. The adsorbent was stable and easy to detect, adsorb and recover Pd(II) ions by charge transfer (intense π-π transition) complexation mechanism. The optimum experimental conditions such as pH, contact time, initial concentration, selectivity and sensitivity, type and amount of eluent for elution and various ionic interferences on detection and sorption were systematically evaluated. The determined maximum sorption capacity was 191.35. mg/g. The proposed method was applied successfully for extraction of Pd(II) in environmental wastewater samples. © 2014 The Korean Society of Industrial and Engineering Chemistry.

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