This study explores mesoporous silica nanoparticles (MSN) synthesized via oil-water biphase stratification and functionalized with n-octyltrichlorosilane (OTS), 3-aminopropyltriethoxysilane (APTES), or both, yielding OMSN, AMSN, and OAMSN. All adsorbents rapidly removed perfluorooctanoic acid (PFOA) from water, reaching 95 % adsorption equilibrium within 10 min. PFOA adsorption kinetics showed that OAMSN, with the largest pore size (14.4 nm), had the highest pseudo-second-order rate constant. Isotherm analysis indicated that both OAMSN and AMSN achieved higher equilibrium loadings across a broad equilibrium concentration range (C_e: 0.2 μg/L - 8 mg/L), which covers environmentally relevant concentration of PFOA. AMSN, with a positively charged surface (point of zero charge = 9), showed the highest maximum adsorption capacity (q_m = 208 mg/g), while OAMSN, combining hydrophobicity and positive charge, achieved a much higher adsorption coefficient (K_d = 1.4 × 10⁵ L/kg at C_e = 50 μg/L). OMSN, the most hydrophobic evaluated by water contact angle measurements, had a high K_d at C_e = 50 μg/L but the lowest q_m. Pore filling calculations showed large variations (0.8 % for MSN to 12 % for AMSN) despite similar pore volumes, highlighting the dominant role of surface chemistry over pore structure. Hydrophobicity governs adsorption at low loadings, while electrostatic interactions become key approaching q_m. Solvent extraction preserved adsorption efficiency in hydrophobic adsorbents (OMSN, OAMSN), while UV-activated persulfate degraded up to 87 % of the loaded PFOA but impaired reuse, especially for functionalized materials. Thus, solvent extraction suits functionalized adsorbents, whereas UV/persulfate is better for regenerating non-functionalized ones.

Carbon nanotubes (CNTs) are a robust material and proven as a promising candidate for a wide range of electronic, optoelectronic and environmental applications. In this work, two different methods were utilized for the preparation of CNTs exhibiting different aspect ratios via chemical vapor deposition (CVD). The as-prepared CNTs were analyzed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂adsorption isotherms, thermogravimetric analysis and Raman spectroscopy in order to investigate their morphological and structural properties. Free-standing CNTs “buckypaper” membranes were fabricated, characterized and tailored to meet the requirements of two applications, i.e., (1) the removal of humic acid (HA) from water and (2) separation of oil-in-water emulsions. It was revealed that the hydrophobic buckypapers showed high separation performance for Shell oil-in-water emulsions filtration, with up to 98% through the accumulation of oil droplets onto the membrane surface. The absorption capacity of buckypaper membranes for various organic liquids (oil, chloroform and toluene) was evaluated over 10 absorption cycles to investigate their recyclability and robustness. Moreover, surface modification was introduced to the pristine CNTs to increase their surface hydrophilicity and improve the pure water permeability of buckypapers. These modified buckypapers showed high flux for HA solutions and excellent HA rejection efficiency up to 95%via size exclusion and electrostatic repulsion mechanisms.

Pure and silver doped ZnO thin films over glass substrate were prepared by sol–gel spin-coating method. Prepared films were calcined at different temperatures. X-ray diffraction and UV–Vis spectroscopy were used to characterize the prepared samples. The photocatalytic activity under solar irradiation of the prepared thin films was tested for the degradation of three azo reactive dyes namely Reactive Red 195, Reactive yellow 145 and Reactive orange 122 as an organic pollutant. 6 wt.% Ag doping ratio showed the highest photocatalytic activity. Various operational parameters such as pH of the solution and initial concentration of the dye have been investigated.