Activated carbon/titanium dioxide (AC/TiO₂) nanohybrids were synthesized by a hydrothermal technique using various weight percent of commercial AC and were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA). The synthesized nanohybrids were applied to photodegradation of Reactive Red-35 (RR-35) dye in aqueous solution using sunlight. Due to the synergistic effect of adsorption and photodegradation activity, AC/TiO₂ nanohybrids were more efficient in treating the aqueous dye solution than that of AC and TiO₂. The maximum (95%) RR-35 dye removal from the water was obtained with 20 wt% AC/TiO₂ within 30 min at natural pH of 5.6. The possible photodegradation mechanism of RR-35 dye with AC/TiO₂ was discussed from the scavenger test. Moreover, AC/TiO₂ was found to be suitable for long-term repeated applications through recyclability experiments. Therefore, AC/TiO₂ nanohybrid is a promising photocatalyst for treating azo dyes especially RR-35 from water.

Advanced engineering of naturally occurring materials opens new doors in nanoscience and nanotechnology for the separation and/or removal of environmental hazards. Here, a series of nanocomposites containing kaolinite and chitosan varying in the range of 20 to 80% (w/w) kaolinite were used for the adsorptive removal of a reactive textile dye, Remazol Red, from an aqueous solution. Batch experiments were carried out to investigate the effects of pH, contact time, and initial dye concentration on the adsorption capacity. Nanocomposites containing 80% kaolinite (w/w) and 20% chitosan (w/w), i.e., NK₈₀C₂₀, showed an equilibrium adsorption capacity of 371.8 mg/g at pH 2.5, which was 5.2 times higher than that of commercial activated charcoal. Moreover, NK₈₀C₂₀ was regenerated instantly up to 99.9% at pH 10. Therefore, NK₈₀C₂₀ can be effectively utilized as a potential adsorbent for the separation of Remazol Red and homologous azo dyes from industrial effluents. We expect that the findings from this study will play a vital role in environmental research leading to advanced applications in water purification.

This study attempted to harness the dual benefit of adsorption and photocatalytic degradation for efficiently removing a model anionic azo dye, Orange G, from an aqueous solution. For this purpose, a series of bifunctional nanohybrids containing different proportions of naturally occurring biopolymer chitosan and ternary photocatalyst made of kaolinite, TiO₂, and ZnO were prepared through the dissolution of chitosan in acid and subsequent deposition on ternary photocatalyst. The characterization through Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and energy dispersive X-ray spectrum (EDS) have confirmed the successful fabrication of nanohybrids from TiO₂ and chitosan. The adsorptive separation of Orange G from the aqueous solution and subsequent degradation under solar irradiation was thoroughly studied by recording the λ_max value of dye in the ultraviolet–visible (UV-Vis) spectrophotometer at various operating conditions of pH, dye concentration, contact time, and compositional variation. The nanohybrid (TP_0.75CS_0.25) fabricated from 75% ternary photocatalyst (w/w) and 25% chitosan (w/w) removed 97.4% Orange G within 110 min at pH 2.5 and 10 mg/L dye concentration. The relative contribution of chitosan and ternary composite on dye removal was understood by comparing the experimental results in the dark and sunlight. Recyclability experiments showed the suitability of the nanohybrid for long-term repeated applications. Equilibrium experimental data showed a better correlation with the Langmuir isotherm and pseudo-second-order kinetic model. The rapid and nearly complete removal capacity, long-term reusability, and simple fabrication technique make this novel nanohybrid a promising advanced material for removing hazardous azo dyes from industrial effluents.

Naturally occurring nanomaterials are finding growing interests in tailoring properties of engineering polymers for advanced applications. The objective of this study was to develop environment-friendly nanocomposite films by reinforcing kaolinite nanofillers (1–10 wt%) in silicone rubber (SR) matrix using a simple solvent casting technique. Kaolinite-reinforced films showed substantial improvement in mechanical (tensile strength, Young’s modulus, and elongation at break) and thermal properties at very low filler loading (5 wt%). The improvement of solvent resistance nature of the fabricated films was another critical aspect of this study. Unfilled SR film showed ~19% weight loss when immersed in toluene for 4 h at 25 °C, whereas only ~4% weight loss was recorded in the case of 5% (w/w) kaolinite loaded film. Therefore, kaolinite has the potential to bring significant improvement in the properties of SR. This study indicates that there is plenty of room at the bottom for proper utilization of the potential of kaolinite for developing SR-based composite materials for potential applications in many industries, such as textile, household cleaning, construction, electronics, automotive, medical, etc.