Awual, M. R.; Hasan, M. M.*; Naushad, M.*; 塩飽 秀啓; 矢板 毅
Sensors and Actuators B; Chemical, 209, p.790 - 797, 2015/03
In this study, we have developed S and N containing ligand of 5-tert-butyl-2-hydroxybenzaldehyde thiosemicarbazone. The organic ligand was anchored onto the mesoporous silica by an indirect method for the preparation of composite adsorbent. The adsorbent can detect Pd(II) ions at ultra-trace levels and recover the Pd(II) with high sorption capacity and efficiency. 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.
Awual, M. R.; Hasan, M. M.*; Khaleque, M. A.*
Sensors and Actuators B; Chemical, 209, p.194 - 202, 2015/03
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.
Awual, M. R.; Hasan, M. M.*
Sensors and Actuators B; Chemical, 206, p.692 - 700, 2015/01
The nitrogen donor ligand was functionalized with polarable mesoporous silica as composite adsorbent, by a cost-effective and environmentally friendly procedure, for highly selective Cu(II) ions detection and removal from water. The composite adsorbent permitted fast and specific Cu(II) ions capturing via colorimetric naked eye detection based on stable complexation mechanism. The adsorbent was selective toward Cu(II) as shown by a light yellow to green color change. This was characterized by UVvis spectroscopy and the color change was observed for the visual detection of Cu(II) ions. The data also confirmed that the adsorbent is a cost-effective and environmentally friendly procedure for Cu(II) treatment.
Awual, M. R.; Hasan, M. M.*; Shahat, A.*
Sensors and Actuators B; Chemical, 203, p.854 - 863, 2014/11
In this study, we designed ligand immobilized mesoporous adsorbent for ultra-trace Pb(II) monitoring and removal from wastewater. 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 data revealed that the adsorbent was able to detect the ultra-trace Pb(II) ions with high sensitivity and selectivity by charge transfer 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.
Awual, M. R.; 矢板 毅; 岡本 芳浩
Sensors and Actuators B; Chemical, 203, p.71 - 80, 2014/11
Organic and inorganic based conjugate materials are important in nanotechnology based on the high functionality and stable complex formation with target metal ions at optimum conditions. A new ligand immobilization based dual and tunable conjugate adsorbent was investigated under specific solution acidity for detection and removal of Co(II) and Cu(II) ions. Under the optimum conditions, the calibration graphs were the linear and detection limit which were 0.52 and 0.41 ppb for Co(II) and Cu(II), respectively. The removal efficiency was carried out as a function of solution pH, initial metal ions concentration, and co-existing diverse ions. Sorption equilibrium was well fitted to Langmuir isotherms and determined sorption capacity was 205.33 and 199.20 mg/g for Co(II) and Cu(II), respectively.
Awual, M. R.; Hasan, M. M.*
Sensors and Actuators B; Chemical, 202, p.395 - 403, 2014/10
The functionalized mesoporous silica based fine tuning meso adsorbent was developed for ultra trace lead (Pb(II)) detection and removal from wastewater. The design of the ligand into ordered pore based meso adsorbent transformed the Pb(II) detection and removal systems into smart and stable assemblies. The ability of the meso adsorbent to detect and remove Pb(II) from aqueous solutions has been studied and discussed with different optimized conditions of concentrations, the amount of meso adsorbent, concentration of coexisting electrolyte and pH. The design of such a tunable meso adsorbent offered a simple procedure in such toxic Pb(II) ions removal without using high tech, sophisticated instruments.
Awual, M. R.; Ismael, M.*
Sensors and Actuators B; Chemical, 196, p.457 - 466, 2014/06
The adsorbent was prepared by indirect and dense immobilization of 6((2(2 hydroxy 1 naphthoyl)hydrazono)methyl) benzoic acid (HMBA) onto fine tuned surface patterning of nanostructure inorganic silica. The small energy gap for the complex compared with the HMBA suggested the easily excitation of electrons according to the electron transfer or energy transferred mechanism, which results in the intense color of the stable complexation mechanism. The influence of several variables such as solution acidity, initial concentrations and the addition of diverse ions for Au(III) detection and recovery has also been considered and evaluated. The detection limit of the conjugate adsorbent at optimum conditions was 0.11 ppb. The Au(III) sorption forms a monolayer on the interior pore surfaces of the conjugate adsorbent and showed high sorption capacity (203.42 mg/g).
Awual, M. R.; Ismael, M.*; 矢板 毅
Sensors and Actuators B; Chemical, 191, p.9 - 18, 2014/02
The composite adsorbent was prepared by indirect immobilization of 6-((2-(2-hydroxy-1-naphthoyl)hydrazono)methyl)benzoic acid (HMBA) onto mesoporous silica monoliths. The composite adsorbent enhanced the color formation by stable complexation as [Co(II)-HMBA] complexes during detection and sorption operations. The effective pH range for Co(II) ions detection and sorption was neutral pH region and the maximum sorption capacity of the adsorbent was as high as 189.37 mg/g.
Awual, M. R.; 矢板 毅
Sensors and Actuators B; Chemical, 183, p.332 - 341, 2013/07
This study aims to develop a novel sensor ensemble adsorbent for rapid sensing and recovery of Pd(II) from water. A highly selective and efficient adsorbent was prepared by immobilization of the synthesized ligand onto mesoporous silica monoliths and applied for successful detection and recovery of Pd(II) ions with high selectivity and sensitivity. The effects of various parameters such as pH, contact time, initial concentration, selectivity and sensitivity, on the detection and sorption of Pd(II) by the adsorbent were investigated. The results showed that the maximum sorption capacity was found at pH3.50 and adsorbent was selectively adsorbed Pd(II) ions from binary and multi mixtures even in the presence of various competing ions. The adsorbent was stable without significant loss of sorption and recovery performances even after several reuses cycles.
El-Safty, S. A.*; Awual, M. R.; Shenashen, M. A.*; Shahat, A.*
Sensors and Actuators B; Chemical, 176, p.1015 - 1025, 2013/01
The novel nanocollector were developed for potential application in cobalt (Co(II)) detection and extraction from lithium ion batteries (LIBs). The nanocollectors are high surface area and large pore volume which possess the ultra-trace Co(II) detection and removal from LIBs. The nanocollectors were retaining functionality in spite of many chemical treatments during removal-extraction-regeneration cycles. Therefore, large scale pilot studies are recommended in order to confirm the promising results obtained at laboratory scale.