Titanium oxide supported palladium (TiO₂/Pd) and titanium oxide supported platinum (TiO₂/Pt) nanoparticles were prepared from their precursors through the incipient wetness method. The TiO₂/Pd and TiO₂/Pt nanoparticles were characterized by scanning electron microscopy (SEM), and energy dispersive X-rays (EDX), while the photodegradation study of methyl violet was performed by UV/VIS spectrophotometry. The morphological study shows that the Pd and Pt were well deposited on the surface of TiO₂, which was confirmed by EDX. Both TiO₂/Pd and TiO₂/Pt nanoparticles were used as photocatalysts for the photodegradation of methyl violet in aqueous media under UV-light irradiation. The photodegradation study revealed that the TiO₂/Pd and TiO₂/Pt nanoparticles degraded about 95 and 78% of dye within 20 min, respectively. The effect of various parameters such as catalyst dosage, concentration of dye, and medium on the photocatalytic degradation was examined. The activity of recovered TiO₂/Pd and TiO₂/Pt nanoparticles was studied.

Zirconia-supported palladium (Pd/ZrO₂) and Zirconia-supported platinum (Pt/ZrO₂) nanoparticles (NPs) are synthesized from their precursors via impregnation technique. The Pd/ZrO₂ and Pt/ZrO₂ NPs were analyzed via SEM and EDX, while the study of indigo disulfonate dye degradation was carried out by UV/VIS spectrophotometer. The SEM micrographs illustrated that the Pd and Pt NPs were well placed on ZrO₂ surface. The Pd/ZrO₂ and Pt/ZrO₂ NPs were also employed as photocatalysts for the photodegradation of indigo disulfonate in an aqueous medium under UV-light irradiation. The photodegradation study presented that Pd/ZrO₂ and Pt/ZrO₂ NPs degraded 96 and 94% of indigo disulfonate in 14 h, respectively. The effect of pH of medium and catalyst dosage and efficiency of recovered Pd/ZrO₂ and Pt/ZrO₂ NPs on the photocatalytic degradation were also studied. It was also found that the maximum degradation of dye was found at pH 10 (95–97%) and at 0.02 g weight (40.28%).

The synergistic effect of binary CdTiO₂ and ternary NiCdTiO₂ on the photocatalytic efficiency of TiO₂ nanoparticles was investigated. The SEM analysis demonstrates spherical TiO₂ NPs of different sizes present in agglomerated form. The structural analysis of the nanocomposites reveals a porous structure for TiO₂ with well deposited Cd and Ni NPs. TEM images show NiCdTiO₂ nanocomposites as highly crystalline particles having spherical and cubical geometry with an average particle size of 20 nm. The EDX and XRD analysis confirm the purity and anatase phase of TiO₂, respectively. Physical features of NiCdTiO₂ nanocomposite were determined via BET analysis which shows that the surface area, pore size and pore volume are 61.2 m²/g, 10.6 nm and 0.1 cm³/g, respectively. The absorbance wavelengths of the CdTiO₂ and NiCdTiO₂ nanocomposites have shown red shift as compared to the neat TiO₂ due to coupling with Ni and Cd that results in the enhanced photocatalytic activity. The photocatalytic activity demonstrated that TiO₂, CdTiO₂ and NiCdTiO₂ degrade methylene blue (MB) and methyl green (MG) about 76.59, 82, 86% and 63.5, 88, 97.5%, respectively, at optimum reaction conditions.

This research work focuses on the isolation and thermo-chemical modification of cellulose and its application as an adsorbent for the removal of organic pollutants. The used cellulose was collected from a locally available plant (Olive Europa) commonly called Zaitoon. The stem branches of Zaitoon were collected and then kept in water for 40–45 days at room temperature to extract the cellulose fibers. These cellulose fibers were then kept in the Soxhlet apparatus for washing in n-hexane for 72 h. The purified cellulose was divided into three parts: one part was subjected to thermal activation (TAC), the second was modified chemically (CMC) with Benzyl Chloride, while the last one remained un-functionalized (UFC). All the three forms of cellulose were characterized via FTIR and SEM, then utilized for the removal of Titan Yellow (TY) dye from aqueous media via adsorption process by varying the contact time, temperature, concentration of dye and type, and dose of adsorbent. The adsorption efficiencies of all adsorbents were compared under different experimental variables. Thermally activated cellulose showed the best results for the removal of TY compared with other materials. The calculated removal percentage of TY was found to be 97.69, 94.83, 94.83, and 98% under equilibrium conditions of contact time, temperature, adsorbent dose, and TY concentration. Similarly, the uptake capacities of TAC under optimal experimental conditions were found to be 19.56, 18.96, 18.52, and 18.75 mg/g. Thermodynamic studies of TAC, CMC, and UFC showed that the values of ΔG are negative, while those of ΔH and ΔS are positive in all cases and at all temperatures. This indicates that the TY elimination process is endothermic and spontaneous with an entropy-driven nature. The obtained results indicate that the as-fabricated low-cost biomaterials can effectively remove dyes from wastewater through physicochemical interactions. The removal process was influenced by the nature of the adsorbent and the operating variables.

Antibacterial resistance is a massive universal health crisis and one of the most significant threats to human life. Many bacterial species have evolved and obtained resistance against multiple drugs. As a result, alternative antibacterial agents are essentially required to fight infections caused by resistant pathogenic bacteria. To study the antibacterial activity of iron nanoparticles against methicillin-resistant Staphylococcus aureus, the nanoparticles were synthesized via the microwave induced precipitation method using an aqueous solution of ferric and ferrous ions (1 : 1.5) M with sodium hydroxide (3 M). The antibacterial activity of iron nanoparticles was compared with that of copper, zinc, and chromium nanoparticles synthesized via the same approach. UV-Visible spectra show the λ_max of iron nanoparticles at 287 nm. EDX spectra confirmed the absence of impurities; SEM images showed smooth morphology, while XRD diffractions revealed the crystallinity of the particles. The resultant iron nanoparticles were functionalized with p-amino benzoic acid (PABA) and anthranilic acid (AA) to enhance their antibacterial activity. Furthermore, bacteria were grown in the presence of non-functionalized and functionalized iron nanoparticles. The inhibition zones in the disc diffusion assay revealed that all the nanoparticles and alum inhibited the growth of Staphylococcus aureus, notably compared to the control samples. Furthermore, the antibacterial activity of functionalized nanoparticles was compared to that of non-functionalized nanoparticles. The result showed that anthranilic acid-functionalized iron nanoparticles (AA@Fe) are more effective against Gram-positive Staphylococcus aureus than non-functionalized nanoparticles and para-aminobenzoic acid-functionalized iron nanoparticles (PABA@Fe). In contrast to the antibacterial activity, PABA@Fe has a good antioxidant activity compared to AA@Fe.