Tamer Mahmoud Tamer Abdelrazik
@srtacity.sci.eg
Polymer research department, Advanced Technology and New Materials Research Institute,
City of Scientific Research and Technological Applications (SRTA-City)
My research interests are largely directed toward utilized of natural or semi-natural polymer in different fields including biomedical, pharmaceutical and environmental applications. This droves me to get a lot of experience in the functionalization and formulation of polymers in different forms like sponges, membranes, hydrogels, and nano-particles. Currently, I am working in the generation of new antimicrobial polymers based on natural source (i.e., polysaccharide and proteins) via functionalized it with biocidal groups. In the same direction but different application, I am working in protection the RO membrane from biofouling by immobilized the surface
EDUCATION
I got my Ph.D. from Ain Shams University in Egypt. My thesis focused on the modification of chitosan for wound dressing application. That included the chemical functionalization of chitosan with various promising groups. Several techniques of preparation, characterization, and evaluation were studied and employed during that period
RESEARCH, TEACHING, or OTHER INTERESTS
Organic Chemistry, Polymers and Plastics, Materials Chemistry, Biomaterials
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Tamer M. Tamer, Rafik Abbas, Wagih A. Sadik, Ahmed M. Omer, Mai M. Abd-Ellatif, and Mohamed S. Mohy-Eldin
Springer Science and Business Media LLC
AbstractThe present study introduces a new and straightforward method for the amination of Chitosan. This method involves coupling Chitosan (CS) with 2-chloroethylamine (ENH2) in a single step to produce an amino-ethyl Chitosan derivatives with increased amine group content (CS-ENH2) using click chemistry. The resulting derivatives were then crosslinked using Glutaraldehyde to form amino-ethyl Chitosan Schiff bases. The novel amino-ethyl Chitosan Schiff bases were subsequently utilized as adsorbents for the removal of Methyl Orange (MO) dye from aqueous solutions using a batch technique, and the performance of the produced Schiff bases was compared with that of the native Chitosan Schiff base. The CS-ENH2 adsorbents show improved adsorption capacity up to 300% of the native Chitosan Schiff base with almost double removal rate. The adsorption temperature has a positive impact in general while almost 100% of MO removed at 60 °C using CS-ENH2 adsorbents compared with 66% of the native Chitosan Schiff base adsorbent. The adsorption pH shows a negative impact on the MO removal percent. That effect reduced sharply using the CS-ENH2 adsorbents with higher amination degree while the MO removal percent almost being constant over a wide range of pH; 2.0–7.0. The agitation speed has the same positive effect over all the adsorbents. However, the rate of MO removal percent decreased with increase the agitation speed up to 250 rpm. The experimental findings demonstrated that the highest percentage of MO dye removal was achieved under the conditions of pH 2.0, a temperature of 60 °C, agitation speed of 250 rpm, and adsorption duration of 90 min. These Schiff bases were subsequently characterized using advanced analytical techniques including Fourier Transform Infrared spectroscopy, Thermal analysis (TGA and DSC), and Scanning Electron Microscopy.
Mohamed A. Hassan, Sarah Abd El-Aziz, Asmaa Nabil-Adam, and Tamer M. Tamer
Elsevier BV
T. Tamer, M. Abou-Krisha, A. Omer, A. Alhamzani, M. Youssef, T. Yousef, R. Khalifa, M. Salem, and M. Mohy-Eldin
Springer Science and Business Media LLC
Asmaa Attya Shalaby, Mohamed Hussien Abd Elmageed, Gihan Farouk Malash, Tamer Mahmoud Tamer, Ahmed Mohamed Omer, Mohamed Samir Mohy-Eldin, Zdenko Špitalský, and Randa Eslah Khalifa
Elsevier BV
Basma M. Omar, Soad A. Abdelgalil, Hala Fakhry, Tamer M. Tamer, and Mervat A. El-Sonbati
Springer Science and Business Media LLC
AbstractOil spills are a significant threat to the marine ecosystem that requires immediate removal from the oceanic environment. Many technologies have been employed to clean up oil spills. Of these, adsorption has scored a prominent success due to the high efficiency, economic viability, environmental friendship, and ease of application. The utilization of agricultural waste to produce biosorbents have been considered as an ecofriendly and efficient approach for removing oil. Thus, a new low-cost oil adsorbent was prepared via esterification of the wheat straw (Str) with a hydrophobic benzoyl group, the resulting copolymer (Str-co-Benz) was characterized by FTIR, TGA, DSC, and SEM and used at laboratory scale. The oil spill cleanup process was conducted using a crude oil-natural seawater system under different adsorption conditions such as oil concentration, adsorbent dose, agitation time and speed. Equilibrium studies were performed to determine the capacity of the prepared materials for crude oil adsorption. Langmuir and Freundlich adsorption models were used to describe the experimental isotherms. The reliability of the data was examined and evaluated via application of response surface methodology program. The results showed that oil adsorption followed a pseudo-second-order kinetic model and fitted well with Langmuir model with a maximum adsorption capacity of 10.989 and 12.786 g/g for Str and (Str-co-Benz), respectively. Overall, the modified wheat husk is an effective platform for removing oil from marine ecosystems due to low cost, biodegradability, simple synthesis and fast removal. Moreover, the resulted solid can be used as a fuel in some industrial processes such as steam boilers and brick production incinerators.
Tamer M. Tamer, Hongyan Zhou, Mohamed A. Hassan, Marwa M. Abu-Serie, Sergey Shityakov, Smaher M. Elbayomi, Mohamed S. Mohy-Eldin, Yongcheng Zhang, and Tuckyun Cheang
Elsevier BV
Bassant Yousry Eweida, Ahmed Mohamed Omer, Tamer Mahmoud Tamer, Hesham Abd-Elfatah Mohamed Soliman, Ahmed Amin Zaatot, and Mohamed Samir Mohy-Eldin
Springer Science and Business Media LLC
AbstractKinetic, isothermal and thermodynamic studies for the oil spills removal process have been conducted by Chitosan and novel amphiphilic Chitosan-g-Octanal Schiff base adsorbents developed by click chemistry and evaluated successfully in the removal of heavy crude oil spills. Chitosan was first prepared from wastes of marine shrimp shells, and then Chitosan and Chitosan-g-Octanal Schiff base adsorbents were synthesized and verified their structures, thermal stability and their morphological changes using FT-IR spectroscopy, TGA and SEM. The oil adsorption percentages (%) using heavy crude oil were 96.41% for the Chitosan-g-Octanal Schiff base adsorbent compared to 64.99% for native Chitosan counterpart. High rate of adsorption was observed where 40% of oil adsorbed within 15 min only using the Chitosan-g-Octanal Schiff base adsorbent compared to 90 min for native Chitosan adsorbent. The adsorption process followed the pseudo-second order model, and the equilibrium data were sufficiently fitted with the Langmuir model with a maximum adsorption capacity 30.30 g/g at 25 °C. Thermodynamic parameters computed from Van’t Hoff plot confirmed the process to be endothermic, favorable and spontaneous.
Tamer M. Tamer, Mervat M. ElTantawy, Arina Brussevich, Anna Nebalueva, Alexander Novikov, Ivan V. Moskalenko, Marwa M. Abu-Serie, Mohamed A. Hassan, Svetlana Ulasevich, and Ekaterina V. Skorb
Elsevier BV
Mohamed A. Hassan, Tamer M. Tamer, Ahmed M. Omer, Walid M.A. Baset, Eman Abbas, and Mohamed S. Mohy-Eldin
Elsevier BV
Asmaa Nabil-Adam, Mohamed L. Ashour, Tamer M. Tamer, Mohamed A. Shreadah, and Mohamed A. Hassan
MDPI AG
Jania rubens red seaweed has various bioactive compounds that can be used for several medicinal and pharmaceutical applications. In this study, we investigate the antidiabetic, anti-inflammatory, and antioxidant competency of Jania rubens polyphenolic extract (JRPE) by assessing their interactions with α-amylase, lipase, and trypsin enzymes. HPLC analysis revealed the dominance of twelve polyphenolic compounds. We performed computational analysis using α-amylase, lipase, and trypsin as target proteins for the polyphenols to explore their activities based on their predicted modes of binding sites following molecular modeling analysis. The molecular docking analysis demonstrated a good affinity score with a noticeable affinity to polyphenolic compositions of Jania rubens. The compounds with the highest affinity score for α-amylase (PDB: 4W93) were kaempferol, quercetin, and chlorogenic acid, with −8.4, −8.8 and −8 kcal/mol, respectively. Similarly, lipase (PDB: 1LPB) demonstrated high docking scores of −7.1, −7.4, and −7.2 kcal/mol for kaempferol, quercetin, and chlorogenic acid, respectively. Furthermore, for trypsin (PDB: 4DOQ) results, kaempferol, quercetin, and chlorogenic acid docking scores were −7.2, −7.2, and −7.1 kcal/mol, respectively. The docking findings were verified using in vitro evaluations, manifesting comparable results. Overall, these findings enlighten that the JRPE has antidiabetic, anti-inflammatory, and antioxidant properties using different diabetics’ enzymes that could be further studied using in vivo investigations for diabetes treatment.
T. M. Tamer, Guangyu Zhang, Mohamed S. Mohy-Eldin, and Zhaohui Su
Springer Science and Business Media LLC
Ahmed M. Omer, Tamer M. Tamer, Mohamed E. Hassan, Randa E. Khalifa, Eman M. Abd El-Monaem, Abdelazeem S. Eltaweil, and Mohamed S. Mohy Eldin
Springer Science and Business Media LLC
AbstractThe present study aimed to develop an efficient superabsorbent hydrogel for water conservation and slow release of Ethephon in sandy soil. Herein, carboxymethyl cellulose (CMC) was grafted via a free radical polymerization technique with acrylamide and 2-Acrylamido-2-methylpropanesulfonic acid (AMPS) as hydrophilic monomers. The developed CMC-g-(PAM-co-PAMPS) graft copolymer superabsorbent hydrogel was characterized by FTIR, TGA, and SEM analysis to prove the occurrence of the grafting process. Several factors affecting the grafting process were investigated, while maximum grafting (%) value reached 91%. Moreover, increasing AMPS ratio obviously improved the swelling degree of the developed hydrogel with a maximal value of 17,770%. Moreover, addition of 2% of hydrogel to sandy soil potentially enhanced the water retention by 47% compared to pure sandy soil which retained about 7% of water. Besides, increasing Ethephon ratio up to 20% significantly increased its loading (%) value up to 88%, while about 87% of Ethephon was released within 28 days in a slow and sustained manner. The results suggested that the fabricated grafted hydrogel can serve as nutrient carrier and amendment for sandy soil for advanced agricultural applications.
Lamia M. El-Samad, Mohamed A. Hassan, Amal A. Basha, Saeed El-Ashram, Eman H. Radwan, Karoline K. Abdul Aziz, Tamer M. Tamer, Maria Augustyniak, and Abeer El Wakil
Elsevier BV
Tamer M. Tamer, Maysa M. Sabet, Zahrah A. H. Alhalili, Ahmed M. Ismail, Mohamed S. Mohy-Eldin, and Mohamed A. Hassan
MDPI AG
Polyvinyl alcohol (PVA) is a safe and biodegradable polymer. Given the unique physical and chemical properties of PVA, we physically cross-linked PVA with kaolin (K) and cedar essential oil (Ced) using the freeze-thawing approach to fabricate PVA/Ced/K sponge hydrogels as hemostatic, antibacterial, and antioxidant wound healing materials. The physicochemical characteristics of PVA/Ced/K hydrogels, including water swelling profiles and gel fractions, were surveyed. Additionally, the functional groups of hydrogels were explored by Fourier transform infrared spectroscopy (FTIR), while their microstructures were studied using scanning electron microscopy (SEM). Furthermore, the thermal features of the hydrogels were probed by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). Evidently, alterations in cedar concentrations resulted in significant variations in size, water uptake profiles, and hydrolytic degradation of the hydrogels. The incorporation of cedar into the PVA/K endowed the hydrogels with significantly improved antibacterial competency against Bacillus cereus (B. cereus) and Escherichia coli (E. coli). Moreover, PVA/Ced/K exhibited high scavenging capacities toward ABTS•+ and DPPH free radicals. Beyond that, PVA/Ced/K hydrogels demonstrated hemocompatibility and fast blood clotting performance in addition to biocompatibility toward fibroblasts. These findings accentuate the prospective implementation of PVA/Ced/K composite hydrogel as a wound dressing.
Mohamed R. El-Aassar, Tamer M. Tamer, Mohamed Y. El-Sayed, Ahmed M. Omer, Ibrahim O. Althobaiti, Mohamed E. Youssef, Rawan F. Alolaimi, Emam F. El-Agammy, Manar S. Alruwaili, Omar O. Rabhy,et al.
MDPI AG
Methylene blue (MB) immobilized onto a sulfonated poly(glycidyl methacrylate) (SPGMA) polymer composite has been developed as a novel adsorbent for water treatment applications. The MB adsorptions onto sulfonated poly(glycidyl methacrylate) polymer characters have been studied. The adsorption isotherms, namely Langmuir and Freundlich, have been investigated. Other isotherm models. As a compromise between the Freundlich and Langmuir isotherm models, such as the D–R isotherm and the Temkin isotherm, have been compared. The results indicated that the adsorption process followed the Freundlich isotherm model, indicating heterogeneous surface site energies and multi-layer levels of sorption. This study selected three linear kinetic models, namely pseudo-first order, pseudo-second order, and Elovich, to describe the MB sorption process using SPGMA negatively charged nanoparticles (430 nm). The obtained data revealed that the adsorption process obeyed the pseudo-second-order kinetic model, suggesting that the rate-limiting step in these sorption processes may be chemisorption. Furthermore, the thermodynamic parameters have been evaluated. Moreover, the interaction of the MB molecules with SPGMA nanoparticles has been simulated using the governing equation that describes ion exchange resin derived from Nernst—Plank equations between two ion species. Finally, the developed MB-SPGMA composite adsorbent (27 mg/g) wastested for the first time for the removal of Cr6+ ions and Mn7+ metal ions from dichromate and permanganate-contaminated waters under mild adsorption conditions, opening a new field of multiuse of the same adsorbent in the removal of more than one contaminant.
Mohamed R. El-Aassar, Tamer M. Tamer, Mohamed Y. El-Sayed, Ahmed M. Omer, Ibrahim O. Althobaiti, Mohamed E. Youssef, Rawan F. Alolaimi, Emam F. El-Agammy, Manar S. Alruwaili, and Mohamed S. Mohy-Eldin
MDPI AG
Methylene blue azo dye (MB) immobilized onto Poly (glycidyl methacrylate-Co-methyl methacrylate), (PGMA-co-PMMA), and sulphonated Poly (glycidyl methacrylate-Co-methyl methacrylate), (SPGMA-co-PMMA), polymers composites have been developed as novel adsorbents for water treatment applications. The effect of copolymer composition and sulphonation on the MB content has been studied. Maximum MB content was correlated to the Polyglycidyl methacrylate content for both native and sulphonated copolymers. Furthermore, the effect of the adsorption conditions on the MB content was studied. Sulfonated Poly (glycidyl methacrylate; SPGMA) was the most efficient formed composite with the highest MB content. The developed composites’ chemical structure and morphology were characterized using characterization tools such as particle size, FTIR, TGA, and SEM analyses. The developed MB-SPGMA composite adsorbent (27 mg/g), for the first time, was tested for the removal of Cr (VI) ions and Mn (VII) metal ions from dichromate and permanganate contaminated waters under mild adsorption conditions, opening a new field of multiuse of the same adsorbent in the removal of more than one contaminants.
Mahmoud Atya El-Meligy, Katarína Valachová, Ivo Juránek, Tamer M. Tamer, and Ladislav Šoltés
MDPI AG
The present study aimed at preparing novel free-radical scavenging and water-soluble compounds derived from gelatin. Specifically, gelatin–syringaldehyde, gelatin–anisaldehyde, and gelatin–vanillin were synthesized and thoroughly studied for their physicochemical properties. In particular, the compounds were characterized by UV-Vis spectroscopy, Fourier-transform infrared spectroscopy, and scanning electron microscopy. Notably, as demonstrated by thermogravimetry and differential scanning calorimetry, all three derivatives exhibited higher thermal stability than gelatin itself. Free-radical scavenging activities of the examined compounds were explored by (i) a standard spectrophotometric ABTS assay and (ii) an assay of oxidative degradation of hyaluronic acid monitored by rotational viscometry. We found that gelatin and gelatin–syringaldehyde demonstrated the highest efficacy in scavenging •OH radicals, whereas gelatin–anisaldehyde was the least effective. The efficacy of scavenging alkyloxy- and alkylperoxy-type free radicals via hydrogen-atom-transferring property was in the following order: gelatin > gelatin–vanillin > gelatin–syringaldehyde > gelatin–anisaldehyde. Electron-donor properties determined using the ABTS assay revealed the following order in one-electron reduction of ABTS•+: gelatin > gelatin–anisaldehyde > gelatin–vanillin > gelatin–syringaldehyde.
Hanaa Mansour, Samia El-Sigeny, Sarah Shoman, Marwa M. Abu-Serie, and Tamer M. Tamer
MDPI AG
The objective of this study was to improve the antibacterial activities of chitosan via N-alkyl substitution using 1-bromohexadecane. Mono and di substitution (Mono-NHD-Ch and Di-NHD-Ch) were prepared and characterized using FT-IR, HNMR, TGA, DSC, and SEM. Elemental analysis shows an increase in the C/N ratio from 5.45 for chitosan to 8.63 for Mono-NHD-Ch and 10.46 for Di-NHD-Ch. The antibacterial properties were evaluated against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus cereus. In the examined microorganisms, the antibacterial properties of the novel alkyl derivatives increased substantially higher than chitosan. The minimum inhibitory concentration (MIC) of Mono-NHD-Ch and Di-NHD-Ch was perceived at 50 μg/mL against tested microorganisms, except for B. cereus. The MTT test was used to determine the cytotoxicity of the produced materials, which proved their safety to fibroblast cells. The findings suggest that the new N-Alkyl chitosan derivatives might be used as antibacterial alternatives to pure chitosan in wound infection treatments.
T.M. Tamer, E.R. Kenawy, M.M. Agwa, S.A. Sabra, M.A. El-meligy, and M.S. Mohy-Eldin
Elsevier BV
Basant Y. Eweida, Tamer M. Tamer, Ahmed M. Omer, Hesham M.A. Soliman, Ahmed A. Zaatot, and Mohamed S. Mohy-Eldin
Desalination Publications
Mohamed A. Hassan, Sarah Abd El-Aziz, Horeya M. Elbadry, Samy A. El-Aassar, and Tamer M. Tamer
Elsevier BV
Abdelazeem S. Eltaweil, Manal Fawzy, Mohamed Hosny, Eman M. Abd El-Monaem, Tamer M. Tamer, and Ahmed M. Omer
Elsevier BV
S. Aboulhadeed, H.M. Ahmed, R.E. Khalifa, A.M. Omer, T.M. Tamer, A. Abdelkhalek, and M.S. Mohy-Eldin
Desalination Publications