Ashraf Ali | Inha University (original) (raw)

Papers by Ashraf Ali

Research paper thumbnail of Evaluation of Insecticidal Potentials of Five Plant Extracts against the Stored Grain Pest, Callosobruchus maculatus (Coleoptera: Bruchidae)

Insects

Plant based insecticides are considered among the most economic and ecofriendly chemicals for the... more Plant based insecticides are considered among the most economic and ecofriendly chemicals for the protection of plants and stored grains. The cowpea weevil (Callosbruchus maculatus) causes more than 90% damage to sored grains in three to six months. The current study investigates insecticidal potentials of five selected botanicals: Melia azedarach, Nicotiana rustica, Azadirachta indica, Nicotiana tabacum and Thuja orientalis. They are explored at six different concentrations (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0%) against C. maculatus and compared to effects of distilled water which is used as a control. Toxicities of 3%(V/V) extracts of N. tabacum, N. rustica, A. indica and T. orientalis against C. maculatus were 100%, 86.11%, 80.56% and 72.22%, respectively. Maximum mortality was caused by N. tabacum and N. rustica (100%), followed by A. indica (82%), whereas minimum mortality was observed in T. orientalis (64%) at 2.5%. Several phytochemicals, alkaloids, saponins, diterphenes, phytost...

Research paper thumbnail of Cheap C18-modified Silica Monolith Particles as HPLC Stationary Phase of Good Separation Efficiency

Bulletin of the Korean Chemical Society, 2015

Research paper thumbnail of Isolation, Characterization and Anticancer Activity of Two Bioactive Compounds from Arisaema flavum (Forssk.) Schott

Molecules

Medicinal plants play important role in the public health sector worldwide. Natural products from... more Medicinal plants play important role in the public health sector worldwide. Natural products from medicinal plants are sources of unlimited opportunities for new drug leads because of their unique chemical diversity. Researchers have focused on exploring herbal products as potential sources for the treatment of cancer, cardiac and infectious diseases. Arisaema flavum (Forssk.) is an important medicinal plant found in the northwest Himalayan regions of Pakistan. It is a poisonous plant and is used as a remedy against snake bites and scorpion stings. In this study, two bioactive compounds were isolated from Arisaema flavum (Forssk.) and their anticancer activity was evaluated against human breast cancer cell line MCF-7 using an MTT assay. The crude extract of Arisaema flavum (Forssk.) was subjected to fractionation using different organic solvents in increasing order of polarity. The fraction indicating maximum activity was then taken for isolation of bioactive compounds using various...

Research paper thumbnail of Development of Narrow-Bore C18 Column for Fast Separation of Peptides and Proteins in High-Performance Liquid Chromatography

Polymers

Separation with high efficiency and good resolution is constantly in demand in the pharmaceutical... more Separation with high efficiency and good resolution is constantly in demand in the pharmaceutical industry. The fast and efficient separation of complex samples such as peptides and proteins is a challenging task. To achieve high efficiency with good resolution, chromatographers are moving towards small particles packed into narrow-bore columns. Silica monolith particles (sub-2 µm) were derivatized with chlorodimethyl octadecyl silane (C18) and packed into stainless steel columns (100 mm × 1.8 mm i.d) by a slurry-packing method. The developed columns were used for the separation of peptides and proteins. A separation efficiency (N) of 40,000 plates/column (400,000 plates/m) was achieved for the mixture of five peptides. Similarly, the fast separation of the peptides was carried out using a high flow rate, and the separation of the five peptides was achieved in one minute with high efficiency (N ≅ 240,000 plates/m). The limit of detection (DL) and the limit of quantification (QL) for...

Research paper thumbnail of Efficient Removal of Pb(II) from Aqueous Medium Using Chemically Modified Silica Monolith

Molecules, 2021

The adsorptive removal of lead (II) from aqueous medium was carried out by chemically modified si... more The adsorptive removal of lead (II) from aqueous medium was carried out by chemically modified silica monolith particles. Porous silica monolith particles were prepared by the sol-gel method and their surface modification was carried out using trimethoxy silyl propyl urea (TSPU) to prepare inorganic–organic hybrid adsorbent. The resultant adsorbent was evaluated for the removal of lead (Pb) from aqueous medium. The effect of pH, adsorbent dose, metal ion concentration and adsorption time was determined. It was found that the optimum conditions for adsorption of lead (Pb) were pH 5, adsorbent dose of 0.4 g/L, Pb(II) ions concentration of 500 mg/L and adsorption time of 1 h. The adsorbent chemically modified SM was characterized by scanning electron microscopy (SEM), BET/BJH and thermo gravimetric analysis (TGA). The percent adsorption of Pb(II) onto chemically modified silica monolith particles was 98%. An isotherm study showed that the adsorption data of Pb(II) onto chemically modif...

Research paper thumbnail of Removal of chromium (VI) from aqueous medium using chemically modified banana peels as efficient low-cost adsorbent

Alexandria Engineering Journal, 2016

The adsorptive removal of hexavalent chromium Cr(VI) from aqueous solutions was investigated by a... more The adsorptive removal of hexavalent chromium Cr(VI) from aqueous solutions was investigated by acrylonitrile grafted banana peels (GBPs). Banana peels were treated with 10% HCl, followed by alkaline hydrolysis with 10% NaOH, and washed thoroughly. The bleaching of alkali hydrolyzed peels was carried out with sodium chlorate (NaClO 3) in the presence of hydrogen peroxide and glacial acetic acid. The grafting co-polymerization of acrylonitrile onto the bleached pulp was initiated by Fenton's reagent (Fe +2 /H 2 O 2). The optimum conditions for adsorption of Cr(VI) were found to be the following: pH 3, adsorbent dose 4 g/L, concentration 400 mg/L and contact time of 120 min. The surface morphology of adsorbent was characterized by scanning electron microscopy (SEM) before and after the adsorption. The adsorption of Cr(VI) onto grafted banana peels (GBPs) was recorded to be 96%. The adsorption data were fully fitted with the Freundlich and Langmuir isotherm model and followed a pseudo-second order kinetic model. Thermodynamic study showed that the adsorption is exothermic and spontaneous. Owing to high efficiency and low cost, grafted banana peels (GBPs) can be used as effective adsorbent for Cr(VI) removal from wastewater.

Research paper thumbnail of Phenol removal from aqueous medium using chemically modified banana peels as low-cost adsorbent

Desalination and Water Treatment, 2015

The removal of phenol from aqueous medium was investigated using chemically modified banana peels... more The removal of phenol from aqueous medium was investigated using chemically modified banana peels as adsorbent. Banana peels were alkali hydrolyzed at 100˚C for 3 h and then filtered and washed thoroughly with deionized water. The pulp was bleached by treating with NaClO 3 and glacial acetic acid. The bleached pulp was treated with Acrylonitrile, Fe + /H 2 O 2 , and glacial acetic acid for grafting copolymerization. A comparative analysis of five adsorbents, untreated banana peels, acid hydrolyzed banana peels, bleached banana peels, alkali hydrolyzed banana peels, and grafted banana peels (GBPs) have also been carried out. It was found that GBPs have the highest adsorption capacity for phenol. The adsorption data are fully fitted with Langmuir isotherm model and follow second-order kinetic model. Thermodynamic study shows that the adsorption of phenol is exothermic and spontaneous. This study shows that chemically modified banana peels particularly GBPs can be used as an efficient and low-cost adsorbent for the removal of phenol from wastewater.

Research paper thumbnail of Decontamination of Cr(VI) and Mn(II) from aqueous media by untreated and chemically treated banana peel: a comparative study

Desalination and Water Treatment, 2014

Untreated banana peels (UTBPs), alkali-hydrolyzed banana peels (AlBPs), acid-hydrolyzed banana pe... more Untreated banana peels (UTBPs), alkali-hydrolyzed banana peels (AlBPs), acid-hydrolyzed banana peels (AcBPs), and bleached banana peels (BBPs) were used as adsorbents separately for the removal of Cr(VI) and Mn(II) from aqueous solution during batch experiments. Different parameters like pH, temperature, contact time, adsorbent dose, and initial concentration were studied. The maximum removal capacities for Cr(VI) were UTBP (45%), AlBP (87%), AcBP, (67%) and BBP (40%). While for Mn(II), the maximum removal capacities of theses adsorbents were UTBP (51%), AlBP (90%), AcBP (74%) and BBP (67%) at optimum conditions. The maximum removal of Cr(VI) and Mn(II) was obtained at initial concentration 3 mg/L, adsorbent dose of 4 g/L, pH 6, and contact time 60 min. It was noted that the metal ions removal capacity of these adsorbents was AlBP > AcBP > UTBP > BBP, which indicated that chemical treatment of banana peels enhances the biosorption of metal ions. This study showed that chemically treated banana peel can be used as suitable and costeffective adsorbent for the removal of Cr(VI) and Mn(II) ions from aqueous solutions.

Research paper thumbnail of Preparation of mixed-mode stationary phase for separation of peptides and proteins in high performance liquid chromatography

Scientific Reports, 2022

Porous silica particles were prepared by sol–gel method with some modification to get wide-pore p... more Porous silica particles were prepared by sol–gel method with some modification to get wide-pore particles. These particles were derivatized with N-phenylmaleimide-methylvinylisocyanate (PMI) and styrene by reversible addition fragmentation chain transfer (RAFT) polymerization to prepare N-phenylmaleimide embedded polystyrene (PMP) stationary phases. Narrow bore stainless steel column (100 × 1.8 mm i.d) was packed by slurry packing method. The chromatographic performance of PMP column was evaluated for the separation of synthetic peptides mixture composed of five peptides (Gly-Tyr, Gly-Leu-Tyr, Gly-Gly-Tyr-Arg, Tyr-Ile-Gly-Ser-Arg, Leucine enkephalin) and tryptic digest of human serum albumin (HAS) respectively. Number of theoretical plates as high as 280,000 plates/m were obtained for peptides mixture at optimum elution condition. Separation performance of the developed column was compared with commercial Ascentis Express RP-Amide column and it was observed that separation performan...

Research paper thumbnail of Sedimentation assisted preparation of ground particles of silica monolith and their C18 modification resulting in a chromatographic phase of improved separation efficiency

The sedimentation procedure has been adopted in production of ground silica monolith particles to... more The sedimentation procedure has been adopted in production of ground silica monolith particles to improve chromatographic separation efficiency of the resultant phase. First, silica monolith particles have been successfully prepared in a large scale by a sol-gel process followed by grinding. The particles after calcination were separated by sedimentation into three zones using an Imhoff sedimentation cone. The particles of the bottom zone were derivatized with a C18 ligand and end-capped. The sedimentation process was found to not only eliminate troublesome minute particles but also narrow down the particle size distribution. The resultant phase was packed in glass lined stainless steel micro-columns. The average number of theoretical plates (N) of the columns for a test mixture was 47,000 and 29,300 for the 300 and 150 mm columns (1 mm internal diameter), corresponding to 157,000/m and 195,000/m, respectively.

Research paper thumbnail of Production of Raw and Ligand-modified Silica Monolith Particles in an Enhanced Scale and their Application in High Performance Liquid Chromatography

Porous silica monolith particles have been successfully prepared in an enhanced scale (80–85 g/ba... more Porous silica monolith particles have been successfully prepared in an enhanced scale (80–85 g/batch) and derivatized with some ligands and packed in micro-columns. The separation efficiencies as high as 127 000 and 175 000 plates /m were achieved with 30 and 15 cm columns packed with C18 modified particles, respectively. The average particle size and particle size distribution were reduced by scale-up and subtle change of the formulation of reaction mixture. This phase also has shown some encouraging possibility for fast analysis. Another phase derivatized with mixed ligands of C8 and urea functionalities showed promising feasibility for proteomic analysis.

Research paper thumbnail of Front Cover

Research paper thumbnail of Open tubular capillary column of 50 í µí»m internal diameter with a very high separation efficiency for the separation of peptides in CEC and LC

A specially designed long open tubular capillary column (50 μm internal diameter and 112 cm effec... more A specially designed long open tubular capillary column (50 μm internal diameter and 112 cm effective length) was prepared by fabrication of a thin three-component co-polymer layer on the inner surface of silica capillary. A pretreated silica capillary was reacted with 4-(chloromethyl)phenyl isocyanate in the presence of dibutyltin dichlo-ride as catalyst followed by sodium diethyl dithiocarbamate. Then a thin polymer layer was made on the inner surface of capillary by reversible addition-fragmentation transfer polymerization of styrene, N-phenylacrylamide, and methacrylic acid. A carefully adjusted formulation of reaction mixture and elaborated procedures were adopted to secure formation of the co-polymer layer of enhanced separation performance. The co-polymer immobilized open tubular capillary column was used for the separation of a synthetic mixture of five peptides and excellent separation efficiency (over 1.7 million per column) was obtained in the capillary electrochromatography mode. Such excellent separation efficiencies of ca. 1 m column have not been obtained in the isocratic elution mode so far. The column was also used for separation of the peptides in the liquid chromatography mode to show very good separation efficiency (average 286 700 per column).

Research paper thumbnail of Title: Removal of Mn(II) from water using chemically modified banana peels as efficient adsorbent

In this study a novel acrylonitrile grafted cellulosic adsorbent is prepared from bleached banana... more In this study a novel acrylonitrile grafted cellulosic adsorbent is prepared from bleached banana
pulp. Banana peels were hydrolyzed with alkali followed by bleaching with sodium chlorate
(NaClO3). The grafting co-polymerization of acrylonitrile onto the bleached pulp was carried out
using Fenton’s reagent (Fe+/H2O2) as initiator. The acrylonitrile grafted cellulosic adsorbent was
used for Mn(II) removal from aqueous solution. The adsorption of Mn(II) onto grafted banana
peels was recorded to be 94 %. The adsorption equilibrium is fitted well by Langmuir isotherm
model. Owing to high efficiency and low cost, grafted banana peels (GBPs) can be used as
effective adsorbent for Mn(II) removal from aqueous solution and industrial waste water.

Research paper thumbnail of Banana peels: A green and efficient adsorbent for heavy metals and phenols

The removal of Cr (VI), Mn (II) and phenol from aqueous medium has been studied on untreated and ... more The removal of Cr (VI), Mn (II) and phenol from aqueous medium has been studied on untreated and chemically modified banana peel. The untreated banana peel (UTBP), alkali hydrolyzed banana peel (AlBP), acid hydrolyzed banana peel (ABP), Bleached banana peel (BBP) and grafted banana peel (GBP) were used as adsorbent for the removal of Cr (VI), Mn (II) ions and phenol from aqueous medium. The lignin and other peptic compounds were removed from banana peels using 1M HCl and NaOH, respectively. The graft copolymerization of acrylonitrile on bleached banana peel was effectively initiated with Fe+2/H2O2. The effect of various parameters like initiator concentration, monomer ratio, temperatures and contact time were studied on grafting. The influence of solution pH, adsorbent dose, initial metal ions, phenol concentration, and contact time were studied during the course of study. The optimum results were obtained at initial concentration of 3 mg/L, adsorbent dose of 4 g/L, contact time 1 h, and pH 6 for Cr (VI) and Mn (II), and pH 8 for phenol

Research paper thumbnail of Removal of chromium (VI) from aqueous medium using chemically modified banana peels as efficient low-cost adsorbent

The adsorptive removal of hexavalent chromium Cr(VI) from aqueous solutions was investigated by a... more The adsorptive removal of hexavalent chromium Cr(VI) from aqueous solutions was investigated by acrylonitrile grafted banana peels (GBPs). Banana peels were treated with 10% HCl, followed by alkaline hydrolysis with 10% NaOH, and washed thoroughly. The bleaching of alkali hydrolyzed peels was carried out with sodium chlorate (NaClO 3) in the presence of hydrogen peroxide and glacial acetic acid. The grafting co-polymerization of acrylonitrile onto the bleached pulp was initiated by Fenton's reagent (Fe +2 /H 2 O 2). The optimum conditions for adsorp-tion of Cr(VI) were found to be the following: pH 3, adsorbent dose 4 g/L, concentration 400 mg/L and contact time of 120 min. The surface morphology of adsorbent was characterized by scanning electron microscopy (SEM) before and after the adsorption. The adsorption of Cr(VI) onto grafted banana peels (GBPs) was recorded to be 96%. The adsorption data were fully fitted with the Freundlich and Langmuir isotherm model and followed a pseudo-second order kinetic model. Thermodynamic study showed that the adsorption is exothermic and spontaneous. Owing to high efficiency and low cost, grafted banana peels (GBPs) can be used as effective adsorbent for Cr(VI) removal from wastewater.

Research paper thumbnail of Cheap C18-modified Silica Monolith Particles as HPLC Stationary Phase

Columns packed with silica-based bonded phases have been used in reversed-phase liquid chromatogr... more Columns packed with silica-based bonded phases have been used in reversed-phase liquid chromatography because of their high porosity, large surface area, compatibility with different solvents, mechanical stability, ease of surface modification, and economic feasibility. Bulk monolithic columns have attracted a considerable amount of interest in the last decade, and both monolithic and packed chromatographic columns have their own advantages and disadvantages. 1-5 The columns packed with particles have a high efficiency but they are accompanied with a high column back pressure due to lower permeability, while the monolithic columns have a high permeability but they result in inferior separation efficiency for the analysis of small molecules in HPLC. In our laboratory, we have been using the pseudo-monolithic silica particles with C-18 ligand 1,14,15 or polystyrene film 1,2,16-18 as packing materials. In the current study, porous partially sub-2 μm silica monolith particles have been prepared by a sol-gel process with a six times increased production scale compared with our previous work. These particles have been chemically modified with a C18 reagent and end-capped with a mixture of trimethylchlorosilane (TMCS) and 1,1,1,3,3,3 hexamethyldisilazane (HMDS) and packed in HPLC columns (1.0 mm × 300 mm). Five analytes (phenol, acetophenone, 4-methyl-2-nitroaniline, benzene, and toluene) are separated with good separation efficiency and resolution by using 60/40 (v/v) ACN/ H 2 O containing 0.1% TFA as the mobile phase with a flow rate of 25 μL/min.

Research paper thumbnail of Phenol removal from aqueous medium using chemically modified banana peels as low-cost adsorbent

The removal of phenol from aqueous medium was investigated using chemically modified banana peels... more The removal of phenol from aqueous medium was investigated using chemically modified banana peels as adsorbent. Banana peels were alkali hydrolyzed at 100˚C for 3 h and then filtered and washed thoroughly with deionized water. The pulp was bleached by treating with NaClO3 and glacial acetic acid. The bleached pulp was treated with Acrylonitrile, Fe+/H2O2, and glacial acetic acid for grafting copolymerization. A comparative analysis of five adsorbents, untreated banana peels, acid hydrolyzed banana peels, bleached banana peels, alkali hydrolyzed banana peels, and grafted banana peels (GBPs) have also been carried out. It was found that GBPs have the highest adsorption capacity for phenol. The adsorption data are fully fitted with Langmuir isotherm model and follow second-order kinetic model. Thermodynamic study shows that the adsorption of phenol is exothermic and spontaneous. This study shows that chemically modified banana peels particularlyGBPs can be used as an efficient and low-cost adsorbent for the removal of phenol from
wastewater.

Research paper thumbnail of Decontamination of Cr(VI) and Mn(II) from aqueous media by untreated and chemically treated banana peel: a comparative study DOI: 10.1080/19443994.2013.876669

Untreated banana peels (UTBPs), alkali-hydrolyzed banana peels (AlBPs), acid-hydrolyzed banana pe... more Untreated banana peels (UTBPs), alkali-hydrolyzed banana peels (AlBPs), acid-hydrolyzed banana peels (AcBPs), and bleached banana peels (BBPs) were used as adsorbents separately for the removal of Cr(VI) and Mn(II) from aqueous solution during batch experiments. Different parameters like pH, temperature, contact time, adsorbent dose, and initial concentration were studied. The maximum removal capacities for Cr(VI) were UTBP (45%), AlBP (87%), AcBP, (67%) and BBP (40%). While for Mn(II), the maximum removal capacities of theses adsorbents were UTBP (51%), AlBP (90%), AcBP (74%) and BBP (67%) at optimum conditions. The maximum removal of Cr(VI) and Mn(II) was obtained at initial concentration 3 mg/L, adsorbent dose of 4 g/L, pH 6, and contact time 60 min. It was noted that the metal ions removal capacity of these adsorbents was AlBP > AcBP > UTBP > BBP, which indicated that chemical treatment of banana peels enhances the biosorption of metal ions. This study showed that chemically treated banana peel can be used as suitable and costeffective adsorbent for the removal of Cr(VI) and Mn(II) ions from aqueous solutions.

Research paper thumbnail of Evaluation of Insecticidal Potentials of Five Plant Extracts against the Stored Grain Pest, Callosobruchus maculatus (Coleoptera: Bruchidae)

Insects

Plant based insecticides are considered among the most economic and ecofriendly chemicals for the... more Plant based insecticides are considered among the most economic and ecofriendly chemicals for the protection of plants and stored grains. The cowpea weevil (Callosbruchus maculatus) causes more than 90% damage to sored grains in three to six months. The current study investigates insecticidal potentials of five selected botanicals: Melia azedarach, Nicotiana rustica, Azadirachta indica, Nicotiana tabacum and Thuja orientalis. They are explored at six different concentrations (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0%) against C. maculatus and compared to effects of distilled water which is used as a control. Toxicities of 3%(V/V) extracts of N. tabacum, N. rustica, A. indica and T. orientalis against C. maculatus were 100%, 86.11%, 80.56% and 72.22%, respectively. Maximum mortality was caused by N. tabacum and N. rustica (100%), followed by A. indica (82%), whereas minimum mortality was observed in T. orientalis (64%) at 2.5%. Several phytochemicals, alkaloids, saponins, diterphenes, phytost...

Research paper thumbnail of Cheap C18-modified Silica Monolith Particles as HPLC Stationary Phase of Good Separation Efficiency

Bulletin of the Korean Chemical Society, 2015

Research paper thumbnail of Isolation, Characterization and Anticancer Activity of Two Bioactive Compounds from Arisaema flavum (Forssk.) Schott

Molecules

Medicinal plants play important role in the public health sector worldwide. Natural products from... more Medicinal plants play important role in the public health sector worldwide. Natural products from medicinal plants are sources of unlimited opportunities for new drug leads because of their unique chemical diversity. Researchers have focused on exploring herbal products as potential sources for the treatment of cancer, cardiac and infectious diseases. Arisaema flavum (Forssk.) is an important medicinal plant found in the northwest Himalayan regions of Pakistan. It is a poisonous plant and is used as a remedy against snake bites and scorpion stings. In this study, two bioactive compounds were isolated from Arisaema flavum (Forssk.) and their anticancer activity was evaluated against human breast cancer cell line MCF-7 using an MTT assay. The crude extract of Arisaema flavum (Forssk.) was subjected to fractionation using different organic solvents in increasing order of polarity. The fraction indicating maximum activity was then taken for isolation of bioactive compounds using various...

Research paper thumbnail of Development of Narrow-Bore C18 Column for Fast Separation of Peptides and Proteins in High-Performance Liquid Chromatography

Polymers

Separation with high efficiency and good resolution is constantly in demand in the pharmaceutical... more Separation with high efficiency and good resolution is constantly in demand in the pharmaceutical industry. The fast and efficient separation of complex samples such as peptides and proteins is a challenging task. To achieve high efficiency with good resolution, chromatographers are moving towards small particles packed into narrow-bore columns. Silica monolith particles (sub-2 µm) were derivatized with chlorodimethyl octadecyl silane (C18) and packed into stainless steel columns (100 mm × 1.8 mm i.d) by a slurry-packing method. The developed columns were used for the separation of peptides and proteins. A separation efficiency (N) of 40,000 plates/column (400,000 plates/m) was achieved for the mixture of five peptides. Similarly, the fast separation of the peptides was carried out using a high flow rate, and the separation of the five peptides was achieved in one minute with high efficiency (N ≅ 240,000 plates/m). The limit of detection (DL) and the limit of quantification (QL) for...

Research paper thumbnail of Efficient Removal of Pb(II) from Aqueous Medium Using Chemically Modified Silica Monolith

Molecules, 2021

The adsorptive removal of lead (II) from aqueous medium was carried out by chemically modified si... more The adsorptive removal of lead (II) from aqueous medium was carried out by chemically modified silica monolith particles. Porous silica monolith particles were prepared by the sol-gel method and their surface modification was carried out using trimethoxy silyl propyl urea (TSPU) to prepare inorganic–organic hybrid adsorbent. The resultant adsorbent was evaluated for the removal of lead (Pb) from aqueous medium. The effect of pH, adsorbent dose, metal ion concentration and adsorption time was determined. It was found that the optimum conditions for adsorption of lead (Pb) were pH 5, adsorbent dose of 0.4 g/L, Pb(II) ions concentration of 500 mg/L and adsorption time of 1 h. The adsorbent chemically modified SM was characterized by scanning electron microscopy (SEM), BET/BJH and thermo gravimetric analysis (TGA). The percent adsorption of Pb(II) onto chemically modified silica monolith particles was 98%. An isotherm study showed that the adsorption data of Pb(II) onto chemically modif...

Research paper thumbnail of Removal of chromium (VI) from aqueous medium using chemically modified banana peels as efficient low-cost adsorbent

Alexandria Engineering Journal, 2016

The adsorptive removal of hexavalent chromium Cr(VI) from aqueous solutions was investigated by a... more The adsorptive removal of hexavalent chromium Cr(VI) from aqueous solutions was investigated by acrylonitrile grafted banana peels (GBPs). Banana peels were treated with 10% HCl, followed by alkaline hydrolysis with 10% NaOH, and washed thoroughly. The bleaching of alkali hydrolyzed peels was carried out with sodium chlorate (NaClO 3) in the presence of hydrogen peroxide and glacial acetic acid. The grafting co-polymerization of acrylonitrile onto the bleached pulp was initiated by Fenton's reagent (Fe +2 /H 2 O 2). The optimum conditions for adsorption of Cr(VI) were found to be the following: pH 3, adsorbent dose 4 g/L, concentration 400 mg/L and contact time of 120 min. The surface morphology of adsorbent was characterized by scanning electron microscopy (SEM) before and after the adsorption. The adsorption of Cr(VI) onto grafted banana peels (GBPs) was recorded to be 96%. The adsorption data were fully fitted with the Freundlich and Langmuir isotherm model and followed a pseudo-second order kinetic model. Thermodynamic study showed that the adsorption is exothermic and spontaneous. Owing to high efficiency and low cost, grafted banana peels (GBPs) can be used as effective adsorbent for Cr(VI) removal from wastewater.

Research paper thumbnail of Phenol removal from aqueous medium using chemically modified banana peels as low-cost adsorbent

Desalination and Water Treatment, 2015

The removal of phenol from aqueous medium was investigated using chemically modified banana peels... more The removal of phenol from aqueous medium was investigated using chemically modified banana peels as adsorbent. Banana peels were alkali hydrolyzed at 100˚C for 3 h and then filtered and washed thoroughly with deionized water. The pulp was bleached by treating with NaClO 3 and glacial acetic acid. The bleached pulp was treated with Acrylonitrile, Fe + /H 2 O 2 , and glacial acetic acid for grafting copolymerization. A comparative analysis of five adsorbents, untreated banana peels, acid hydrolyzed banana peels, bleached banana peels, alkali hydrolyzed banana peels, and grafted banana peels (GBPs) have also been carried out. It was found that GBPs have the highest adsorption capacity for phenol. The adsorption data are fully fitted with Langmuir isotherm model and follow second-order kinetic model. Thermodynamic study shows that the adsorption of phenol is exothermic and spontaneous. This study shows that chemically modified banana peels particularly GBPs can be used as an efficient and low-cost adsorbent for the removal of phenol from wastewater.

Research paper thumbnail of Decontamination of Cr(VI) and Mn(II) from aqueous media by untreated and chemically treated banana peel: a comparative study

Desalination and Water Treatment, 2014

Untreated banana peels (UTBPs), alkali-hydrolyzed banana peels (AlBPs), acid-hydrolyzed banana pe... more Untreated banana peels (UTBPs), alkali-hydrolyzed banana peels (AlBPs), acid-hydrolyzed banana peels (AcBPs), and bleached banana peels (BBPs) were used as adsorbents separately for the removal of Cr(VI) and Mn(II) from aqueous solution during batch experiments. Different parameters like pH, temperature, contact time, adsorbent dose, and initial concentration were studied. The maximum removal capacities for Cr(VI) were UTBP (45%), AlBP (87%), AcBP, (67%) and BBP (40%). While for Mn(II), the maximum removal capacities of theses adsorbents were UTBP (51%), AlBP (90%), AcBP (74%) and BBP (67%) at optimum conditions. The maximum removal of Cr(VI) and Mn(II) was obtained at initial concentration 3 mg/L, adsorbent dose of 4 g/L, pH 6, and contact time 60 min. It was noted that the metal ions removal capacity of these adsorbents was AlBP > AcBP > UTBP > BBP, which indicated that chemical treatment of banana peels enhances the biosorption of metal ions. This study showed that chemically treated banana peel can be used as suitable and costeffective adsorbent for the removal of Cr(VI) and Mn(II) ions from aqueous solutions.

Research paper thumbnail of Preparation of mixed-mode stationary phase for separation of peptides and proteins in high performance liquid chromatography

Scientific Reports, 2022

Porous silica particles were prepared by sol–gel method with some modification to get wide-pore p... more Porous silica particles were prepared by sol–gel method with some modification to get wide-pore particles. These particles were derivatized with N-phenylmaleimide-methylvinylisocyanate (PMI) and styrene by reversible addition fragmentation chain transfer (RAFT) polymerization to prepare N-phenylmaleimide embedded polystyrene (PMP) stationary phases. Narrow bore stainless steel column (100 × 1.8 mm i.d) was packed by slurry packing method. The chromatographic performance of PMP column was evaluated for the separation of synthetic peptides mixture composed of five peptides (Gly-Tyr, Gly-Leu-Tyr, Gly-Gly-Tyr-Arg, Tyr-Ile-Gly-Ser-Arg, Leucine enkephalin) and tryptic digest of human serum albumin (HAS) respectively. Number of theoretical plates as high as 280,000 plates/m were obtained for peptides mixture at optimum elution condition. Separation performance of the developed column was compared with commercial Ascentis Express RP-Amide column and it was observed that separation performan...

Research paper thumbnail of Sedimentation assisted preparation of ground particles of silica monolith and their C18 modification resulting in a chromatographic phase of improved separation efficiency

The sedimentation procedure has been adopted in production of ground silica monolith particles to... more The sedimentation procedure has been adopted in production of ground silica monolith particles to improve chromatographic separation efficiency of the resultant phase. First, silica monolith particles have been successfully prepared in a large scale by a sol-gel process followed by grinding. The particles after calcination were separated by sedimentation into three zones using an Imhoff sedimentation cone. The particles of the bottom zone were derivatized with a C18 ligand and end-capped. The sedimentation process was found to not only eliminate troublesome minute particles but also narrow down the particle size distribution. The resultant phase was packed in glass lined stainless steel micro-columns. The average number of theoretical plates (N) of the columns for a test mixture was 47,000 and 29,300 for the 300 and 150 mm columns (1 mm internal diameter), corresponding to 157,000/m and 195,000/m, respectively.

Research paper thumbnail of Production of Raw and Ligand-modified Silica Monolith Particles in an Enhanced Scale and their Application in High Performance Liquid Chromatography

Porous silica monolith particles have been successfully prepared in an enhanced scale (80–85 g/ba... more Porous silica monolith particles have been successfully prepared in an enhanced scale (80–85 g/batch) and derivatized with some ligands and packed in micro-columns. The separation efficiencies as high as 127 000 and 175 000 plates /m were achieved with 30 and 15 cm columns packed with C18 modified particles, respectively. The average particle size and particle size distribution were reduced by scale-up and subtle change of the formulation of reaction mixture. This phase also has shown some encouraging possibility for fast analysis. Another phase derivatized with mixed ligands of C8 and urea functionalities showed promising feasibility for proteomic analysis.

Research paper thumbnail of Front Cover

Research paper thumbnail of Open tubular capillary column of 50 í µí»m internal diameter with a very high separation efficiency for the separation of peptides in CEC and LC

A specially designed long open tubular capillary column (50 μm internal diameter and 112 cm effec... more A specially designed long open tubular capillary column (50 μm internal diameter and 112 cm effective length) was prepared by fabrication of a thin three-component co-polymer layer on the inner surface of silica capillary. A pretreated silica capillary was reacted with 4-(chloromethyl)phenyl isocyanate in the presence of dibutyltin dichlo-ride as catalyst followed by sodium diethyl dithiocarbamate. Then a thin polymer layer was made on the inner surface of capillary by reversible addition-fragmentation transfer polymerization of styrene, N-phenylacrylamide, and methacrylic acid. A carefully adjusted formulation of reaction mixture and elaborated procedures were adopted to secure formation of the co-polymer layer of enhanced separation performance. The co-polymer immobilized open tubular capillary column was used for the separation of a synthetic mixture of five peptides and excellent separation efficiency (over 1.7 million per column) was obtained in the capillary electrochromatography mode. Such excellent separation efficiencies of ca. 1 m column have not been obtained in the isocratic elution mode so far. The column was also used for separation of the peptides in the liquid chromatography mode to show very good separation efficiency (average 286 700 per column).

Research paper thumbnail of Title: Removal of Mn(II) from water using chemically modified banana peels as efficient adsorbent

In this study a novel acrylonitrile grafted cellulosic adsorbent is prepared from bleached banana... more In this study a novel acrylonitrile grafted cellulosic adsorbent is prepared from bleached banana
pulp. Banana peels were hydrolyzed with alkali followed by bleaching with sodium chlorate
(NaClO3). The grafting co-polymerization of acrylonitrile onto the bleached pulp was carried out
using Fenton’s reagent (Fe+/H2O2) as initiator. The acrylonitrile grafted cellulosic adsorbent was
used for Mn(II) removal from aqueous solution. The adsorption of Mn(II) onto grafted banana
peels was recorded to be 94 %. The adsorption equilibrium is fitted well by Langmuir isotherm
model. Owing to high efficiency and low cost, grafted banana peels (GBPs) can be used as
effective adsorbent for Mn(II) removal from aqueous solution and industrial waste water.

Research paper thumbnail of Banana peels: A green and efficient adsorbent for heavy metals and phenols

The removal of Cr (VI), Mn (II) and phenol from aqueous medium has been studied on untreated and ... more The removal of Cr (VI), Mn (II) and phenol from aqueous medium has been studied on untreated and chemically modified banana peel. The untreated banana peel (UTBP), alkali hydrolyzed banana peel (AlBP), acid hydrolyzed banana peel (ABP), Bleached banana peel (BBP) and grafted banana peel (GBP) were used as adsorbent for the removal of Cr (VI), Mn (II) ions and phenol from aqueous medium. The lignin and other peptic compounds were removed from banana peels using 1M HCl and NaOH, respectively. The graft copolymerization of acrylonitrile on bleached banana peel was effectively initiated with Fe+2/H2O2. The effect of various parameters like initiator concentration, monomer ratio, temperatures and contact time were studied on grafting. The influence of solution pH, adsorbent dose, initial metal ions, phenol concentration, and contact time were studied during the course of study. The optimum results were obtained at initial concentration of 3 mg/L, adsorbent dose of 4 g/L, contact time 1 h, and pH 6 for Cr (VI) and Mn (II), and pH 8 for phenol

Research paper thumbnail of Removal of chromium (VI) from aqueous medium using chemically modified banana peels as efficient low-cost adsorbent

The adsorptive removal of hexavalent chromium Cr(VI) from aqueous solutions was investigated by a... more The adsorptive removal of hexavalent chromium Cr(VI) from aqueous solutions was investigated by acrylonitrile grafted banana peels (GBPs). Banana peels were treated with 10% HCl, followed by alkaline hydrolysis with 10% NaOH, and washed thoroughly. The bleaching of alkali hydrolyzed peels was carried out with sodium chlorate (NaClO 3) in the presence of hydrogen peroxide and glacial acetic acid. The grafting co-polymerization of acrylonitrile onto the bleached pulp was initiated by Fenton's reagent (Fe +2 /H 2 O 2). The optimum conditions for adsorp-tion of Cr(VI) were found to be the following: pH 3, adsorbent dose 4 g/L, concentration 400 mg/L and contact time of 120 min. The surface morphology of adsorbent was characterized by scanning electron microscopy (SEM) before and after the adsorption. The adsorption of Cr(VI) onto grafted banana peels (GBPs) was recorded to be 96%. The adsorption data were fully fitted with the Freundlich and Langmuir isotherm model and followed a pseudo-second order kinetic model. Thermodynamic study showed that the adsorption is exothermic and spontaneous. Owing to high efficiency and low cost, grafted banana peels (GBPs) can be used as effective adsorbent for Cr(VI) removal from wastewater.

Research paper thumbnail of Cheap C18-modified Silica Monolith Particles as HPLC Stationary Phase

Columns packed with silica-based bonded phases have been used in reversed-phase liquid chromatogr... more Columns packed with silica-based bonded phases have been used in reversed-phase liquid chromatography because of their high porosity, large surface area, compatibility with different solvents, mechanical stability, ease of surface modification, and economic feasibility. Bulk monolithic columns have attracted a considerable amount of interest in the last decade, and both monolithic and packed chromatographic columns have their own advantages and disadvantages. 1-5 The columns packed with particles have a high efficiency but they are accompanied with a high column back pressure due to lower permeability, while the monolithic columns have a high permeability but they result in inferior separation efficiency for the analysis of small molecules in HPLC. In our laboratory, we have been using the pseudo-monolithic silica particles with C-18 ligand 1,14,15 or polystyrene film 1,2,16-18 as packing materials. In the current study, porous partially sub-2 μm silica monolith particles have been prepared by a sol-gel process with a six times increased production scale compared with our previous work. These particles have been chemically modified with a C18 reagent and end-capped with a mixture of trimethylchlorosilane (TMCS) and 1,1,1,3,3,3 hexamethyldisilazane (HMDS) and packed in HPLC columns (1.0 mm × 300 mm). Five analytes (phenol, acetophenone, 4-methyl-2-nitroaniline, benzene, and toluene) are separated with good separation efficiency and resolution by using 60/40 (v/v) ACN/ H 2 O containing 0.1% TFA as the mobile phase with a flow rate of 25 μL/min.

Research paper thumbnail of Phenol removal from aqueous medium using chemically modified banana peels as low-cost adsorbent

The removal of phenol from aqueous medium was investigated using chemically modified banana peels... more The removal of phenol from aqueous medium was investigated using chemically modified banana peels as adsorbent. Banana peels were alkali hydrolyzed at 100˚C for 3 h and then filtered and washed thoroughly with deionized water. The pulp was bleached by treating with NaClO3 and glacial acetic acid. The bleached pulp was treated with Acrylonitrile, Fe+/H2O2, and glacial acetic acid for grafting copolymerization. A comparative analysis of five adsorbents, untreated banana peels, acid hydrolyzed banana peels, bleached banana peels, alkali hydrolyzed banana peels, and grafted banana peels (GBPs) have also been carried out. It was found that GBPs have the highest adsorption capacity for phenol. The adsorption data are fully fitted with Langmuir isotherm model and follow second-order kinetic model. Thermodynamic study shows that the adsorption of phenol is exothermic and spontaneous. This study shows that chemically modified banana peels particularlyGBPs can be used as an efficient and low-cost adsorbent for the removal of phenol from
wastewater.

Research paper thumbnail of Decontamination of Cr(VI) and Mn(II) from aqueous media by untreated and chemically treated banana peel: a comparative study DOI: 10.1080/19443994.2013.876669

Untreated banana peels (UTBPs), alkali-hydrolyzed banana peels (AlBPs), acid-hydrolyzed banana pe... more Untreated banana peels (UTBPs), alkali-hydrolyzed banana peels (AlBPs), acid-hydrolyzed banana peels (AcBPs), and bleached banana peels (BBPs) were used as adsorbents separately for the removal of Cr(VI) and Mn(II) from aqueous solution during batch experiments. Different parameters like pH, temperature, contact time, adsorbent dose, and initial concentration were studied. The maximum removal capacities for Cr(VI) were UTBP (45%), AlBP (87%), AcBP, (67%) and BBP (40%). While for Mn(II), the maximum removal capacities of theses adsorbents were UTBP (51%), AlBP (90%), AcBP (74%) and BBP (67%) at optimum conditions. The maximum removal of Cr(VI) and Mn(II) was obtained at initial concentration 3 mg/L, adsorbent dose of 4 g/L, pH 6, and contact time 60 min. It was noted that the metal ions removal capacity of these adsorbents was AlBP > AcBP > UTBP > BBP, which indicated that chemical treatment of banana peels enhances the biosorption of metal ions. This study showed that chemically treated banana peel can be used as suitable and costeffective adsorbent for the removal of Cr(VI) and Mn(II) ions from aqueous solutions.