Syed Abdul Monim

Sr _x La _{2– x} NiMnO ₆ , a bi-functional adsorbent and photocatalyst for trypan blue adsorption with UV-driven in situ regeneration, enabling adsorbent reuse.

A simple sol-gel method was developed to synthesize La2NiMnO6 (LNMO) double perovskite in nano dimensions, which was evaluated for the effective adsorptive removal of m-cresol from aqueous solutions. The structural and chemical properties of the synthesized LNMO were characterized using X-ray Diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The LNMO material possessed a hexagonal crystal structure and an average particle size of approximately 50 nm, which contributed to improving adsorptive properties. Furthermore, adsorption studies revealed that m-Cresol removal is significantly pH dependent, as maximum adsorption was found at pH 2. As a weak acid, m-cresol exists in its neutral form in acidic conditions and promotes interaction through hydrogen bonding and Lewis acid-base interactions with LNMO's surface. Moreover, adsorption isotherms were analyzed using Langmuir, Freundlich, and Temkin model where the Langmuir model fitted the best, indicating a maximum adsorption capacity of 204 mg/g while the values of Langmuir equilibrium constant (KL) of 0.1158 L/mg, and a dimensionless constant (RL) of 0.256, suggesting a favorable adsorption process. Thermodynamic parameters like Gibbs free energy (ΔGo), enthalpy (ΔHo), and entropy change (ΔSo) were analyzed, and it revealed that the adsorption process is spontaneous, heat-releasing, and leads to reduced randomness at the solid-liquid interface. Hence, this study demonstrates the exceptional potential of LNMO as an efficient, cost-effective adsorbent for m-cresol removal, offering valuable insights for the development of novel material for wastewater treatment. Dhaka Univ. J. Sci. 74(1): 17-26, 2026 (January)

Bioactive metal and metal oxide-based nanocomposite hydrogels exhibit significant antibacterial properties by interacting with microbial DNA and preventing bacterial replication. They offer potential applications as coating materials for human or animal skin injuries to prevent microbial growth and promote healing. In this study, silver nanoparticles (AgNPs) were synthesized using a chemical reduction method and incorporated into a polymer network to fabricate silver nanocomposite hydrogels (AgNCHGs) through a simple free radical polymerization method. N-isopropylacrylamide (NIPA), which has lower critical solution temperature (LCST) at about body temperature, or acrylamide (AAm) was used as the main monomer, while one or more ionic co-monomers, such as acrylic acid (AAc) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS), were incorporated to obtain AgNCHGs. AgNPs were introduced into the hydrogel network via three different approaches. In the first method, the synthesized hydrogel was immersed in a silver nitrate (AgNO₃) solution and reduced in situ using sodium borohydride (NaBH₄) as a reducing agent. The second method involved mixing AgNO₃ with gel precursors before reduction with NaBH₄ to form AgNPs within the hydrogel. The final approach synthesized the AgNCHGs directly in a dispersion of pre-fabricated AgNPs. The incorporation of AgNPs in different AgNCHGs was confirmed through various characterization techniques. Varying temperature and pH conditions can trigger the release of bioactive AgNPs from the hydrogels. Furthermore, the antimicrobial and wound-healing properties of the AgNCHGs were evaluated against bacteria and fungi, demonstrating their potential in biomedical applications. In addition, AgNCHGs exhibit excellent electrical conductivity. The electrical conductivity of the hydrogels can be finely tuned by adjusting the concentration of AgNPs, making these materials promising candidates for energy, sensor, and stretchable electronics applications. This study presents facile synthesis methods of AgNCHGs, which integrate bioactivity, wound healing, and electrical conductivity in the same matrix, addressing a significant challenge in designing multifunctional hydrogels for next-generation technologies.

Polyethyleneterephthalate (PET) based proton exchange membrane for using in fuel cells was successfully prepared by gamma radiation-induced graft copolymerization of styrene monomer onto PET film and the consequent selective sulfonation of the grafting chain in the film state using chlorosulfonic acid (ClSO₃H). The effects of grafting conditions (e.g., monomer concentration, irradiation dose) on the degree of grafting and sulfonation condition (e.g., optimum concentration of ClSO₃H) on the degree of sulfonation were studied. The degree of grafting, the degree of sulfonation and the physico-chemical properties (such as, water uptake, mechanical strength, thermal durability, hydrolytic stability, oxidative stability) of the gamma radiation-induced grafted membrane were found to be better when compared to those of the UV-radiation grafted membrane. The membrane shows higher ion exchange capacity (0.9 mmol g⁻¹) and higher proton conductivity (0.075 S cm⁻¹), similar to those of Nafion membrane.