Buffing dust, generated from tannery industries, is a source of air pollution in Pakistan. Valorization of the waste into another useful material is important to deal with the environmental pollution, while reducing waste disposal costs in landfills. To demonstrate its technological strength, this work fabricates a thermal insulation material made of plaster of Paris and the buffing dust (from tanning waste) in the form of a composite with superior mechanical properties and low thermal conductivity. Buffing dust with concentrations ranging from 5 to 20% (w/w) were loaded in the composite. The samples synthesized were made slurry of plaster of Paris, buffing dust, and water at ambient temperature. The physico-mechanical properties of composite were analyzed. It was found that the composite had better thermal insulation properties than the panels of the plaster of Paris. Its thermal conductivity was reduced to 15% after adding buffing dust (20% w/w). All the materials had physico-chemical properties like tensile strength (0.02 MPa and 0.06 MPa), density (700-400 kg/m3), water absorption (5.2-8.6%) and thermal conductivity (0.17000-0.09218 W/m-K). Thermogravimetric analysis showed that the material was thermally stable at temperatures ranging from 145 to 177 °C, while FT-IR results revealed that the composite contained O-H, N-H, and CO functional groups. SEM analysis displayed that the composite's homogeneity was reduced with low voids due to buffing dust addition, while EDX analysis showed that the composite contained 23.62% of S, 26.76% of Ca, 49.2% of O and 0.42% of C. This implies that buffing dust could be recycled to manufacture heat insulation materials for construction sector to reduce air pollution, while minimizing energy consumption. By integrating the buffing dust from tanning waste and the plaster of Paris as a composite for construction sector, this work promotes the recycling of unused waste, while saving public funds. Instead of paying landfill fees and polluting soil, the waste may be recycled at lower cost, while reducing environmental damage.
Textile wastewater laden with dyes has emerged as a source of water pollution. This possesses a challenge in its effective treatment using a single functional material. In respond to this technological constraint, this work presents multifunctional cotton fabrics (CFs) within a single, streamlined preparation process. This approach utilizes the adherence of Ag NPs (nanoparticles) using Si binder on the surface of CFs, resulting in Ag-coated CFs through a pad dry method. The prepared samples were characterized using scanning electron microscope-energy dispersive X-ray electroscopy (SEM-EDS), thermal gravimetric analysis (TGA), Fourier transformation infrared (FT-IR). It was found that the FT-IR spectra of Ag NPs-coated CFs had peaks appear at 3400, 2900, and 1200 cm-1, implying the stretching vibrations of O-H, C-H, and C-O, respectively. Based on the EDX analysis, the presence of C, O, and Ag related to the coated CFs were detected. After coating the CFs with varying concentrations of Ag NPs (1%, 2% and 3% (w/w)), they were used to remove dyes. Under the same concentration of 10 mg/L and optimized pH 7.5 and 2 h of reaction time, 3% (w/w) Ag-coated CFs exhibited a substantial MB degradation of 98 %, while removing 95% of methyl orange, 85% of rhodamine B, and 96% of Congo red, respectively, following 2 h of Vis exposure. Ag NPs had a strong absorption at 420 nm with 2.51 eV of energy band gap. Under UV irradiation, electrons excited and produced free radicals that promoted dyes photodegradation. The oxidation by-products included p-dihydroxybenzene and succinic acid. Spent Ag-coated CFs attained 98% of regeneration efficiency. The utilization of Ag-coated CFs as a photocatalyst facilitated treated effluents to meet the required discharge standard of lower than 1 mg/L mandated by national legislation. The integration of multifunctional CFs in the treatment system presents a new option for tackling water pollution due to dyes.