Preparation of activated porous glass adsorbent through thermochemical reforming of ampoules and eggshells for remediation of direct blue dye pollution

Exploration of solid waste materials for sustainable manufacturing of cementitious composites

The problem of disposing and managing solid waste materials has become one of the major environmental, economic, and social issues. Utilization of solid wastes in the production of building materials not only solves the problem of their disposal but also helps in the conversion of wastes into useful and cost-effective products. In the present study, solid waste materials of organic and inorganic nature were applied in the production of sustainable cementitious composites (CC) and studied the effect of incorporated wastes on physical and mechanical properties of the resultant CC. The selected solid waste materials were cotton, polyester, PET, carpet, glass, and granulated blast furnace slag (GBFS). These wastes were incorporated in CC in different proportions and form the tuff tiles using moulds (12.5″ × 6″ × 2.5″). The various physical (fineness, setting time, bulk density, and water absorption capacity) and mechanical (flexural strength) properties of all the specimens were determined after curing period of 3, 7, and 28 days. The results show that the incorporation of solid wastes in CC did not much affect their physical characteristics. However, the CC incorporated with the selected solid waste materials have a pronounced effect of their flexural strength and found to be higher (12-875%) compared to the plain CC. Similarly, the incorporation of the selected inorganic wastes (302-715 psi) in CC exhibit much higher flexural strength compared to the organic wastes (136-235 psi). The maximum flexural strength was observed when GBFS was utilized as a solid waste. The present work will provide a reliable step for the solid waste management and conversion of such wastes into useful commercial products for concrete manufacturing.

Effect of nanodiamond particles on the structure, mechanical, and thermal properties of polymer embedded ND/PMMA composites

Nanodiamonds (NDs), the allotropic carbon nanomaterials with nanosize, durable inert core, adjustable surface morphology, high thermal constancy, and super mechanical performances, possess the characteristics of promising reinforcement materials for various technological applications. However, ND particles hold a vigorous propensity to aggregate in liquid media, obstructing their implementation in mechanical and thermal sciences. This aggregation is caused by high surface to volume ratio. By reducing the surface energy and lowering cluster formation, the mechanical and thermal properties of NDs can be polished. Herein, we report on the covalent functionalization of NDs with amine moiety through ball milling method. Their dispersion was checked in ethanol and polymethyl methacrylate (PMMA polymer) against nonfunctionalized NDs. The dispersive behavior showed that ball mill functionalized NDs produced preferably stable aqueous dispersions in ethanol media. Furthermore, 0.1, 0.2, and 0.4 wt% ND/PMMA composites were synthesized, and their mechanical and thermal behaviors were studied in terms of hardness, compression, Young`s modulus, flexural strength, tensile strength, and thermogravimetric analysis (TGA). Results revealed that the composites containing 0.2 wt% functionalized ND loaded with PMMA matrix showed outstanding mechanical and thermal performances indicating that 0.2 wt% is the optimum amount for achieving excellent outcomes.

Preparation and comparative evaluation of PVC/PbO and PVC/PbO/graphite based conductive nanocomposites

Two series, A and B, of PVC based nanocomposite polymer membranes (nCPMs) were prepared using PbO only and PbO/graphite mixture as a filler by solution casting method. Seven samples with varying compositions (5–35%) of filler particles were prepared for each series and were compared by thickness measurements, porosity, water uptake, swelling degree, ionic conductivity, ion exchange capacity (IEC), membrane potential and transport number. The maximum values for these characteristics were observed as 0.402 mm, 0.77, 141.3%, 0.11, 0.0033 Scm−1, 8.6 milli-eq.g−1, 0.19 V and 0.01391 for series-A composites whereas that of 0.367 mm, 0.83, 63.4%, 0.019, 0.00981 Scm−1, 5.21 milli-eq.g−1, 0.13 V and 0.0108 for series-B nCPMs respectively. The SEM images of membranes showed greater voids produced in the series-B compared to series-A composites. The maximum Ionic conductivity, IEC, membrane potential and transport number were observed for membrane with 25% PbO/graphite, 20% PbO and 35% PbO particles respectively.

Spectroscopic characterization of biosynthesized lead oxide (PbO) nanoparticles and their applications in PVC/graphite-PbO nanocomposites

Extract of Hibiscus rosa-sinensis plants was used for the green synthesis of PbO nanoparticles. The prepared nanoparticles were conformed with the help of SEM, X-ray diffraction, FTIR and UV-visible spectroscopy. The prepared PbO nanoparticles were dispersed in deionized water and mixed with graphite to get graphite-PbO (G-PbO) filler. Seven different nanocomposite membranes with variable compositions (5, 10, 15, 20, 25, 30 and 35%) of PVC/G-PbO were prepared in tetrahydrofuran (THF) solvent using solution casting method. Different physiochemical parameters of the nanocomposite membranes studied included morphology, porosity, density, water uptake, swelling degree, electrical conductivity and proton adsorption capacity. All these physiochemical parameters were compared with pure PVC membranes available in literature. It was found that the addition of G-PbO filler in PVC polymer improved all the physiochemical properties except density. PVC/G-PbO membranes showed 42.65 times more electrical conductivity and 5.90 times more ion adsorption capacities compare to pure PVC membranes.

Extended visible light driven photocatalytic hydrogen generation by electron induction from g-C3N4 nanosheets to ZnO through the proper heterojunction

The alarming energy crises has forced the scientific community to work for sustainable energy modules to meet energy requirements. As for this, ZnO/g-C3N4 nanocomposites with proper heterojunction were fabricated by coupling a proper amount of ZnO with 2D graphitic carbon nitride (g-C3N4) nanosheets and the obtained nanocomposites were applied for photocatalytic hydrogen generation from water under visible light illumination (λ > 420 nm). The morphologies and the hydrogen generation performance of fabricated photocatalysts were characterized in detail. Results showed that the optimized 5ZnO/g-C3N4 nanocomposite produced 70 µmol hydrogen gas in 1 h compare to 8 µmol by pure g-C3N4 under identical illumination conditions in the presence of methanol without the addition of cocatalyst. The much improved photoactivities of the nanocomposites were attributed to the enhanced charge separation through the heterojunction as confirmed from photoluminescence study, capacity of the fabricated samples for •OH radical generation and steady state surface photovoltage spectroscopic (SS-SPS) measurements. We believe that this work would help to fabricate low cost and effective visible light driven photocatalyst for energy production.

Synthesis and physiochemical performances of PVC-sodium polyacrylate and PVC-sodium polyacrylate-graphite composite polymer membrane

Three types (type-A, B, and C) of composite polymeric membranes (CPMs) based on poly vinyl chloride (PVC) and different fillers (sodium polyacrylate and sodium polyacrylate-graphite) soaked in water and 0.5 N HCl were prepared using solvent casting method. Different physicochemical parameters such as microscopic surface study, water uptake, perpendicular swelling, density, porosity (ε), ion exchange capacity, and conductivity of the as the prepared CPMs were evaluated. Interestingly, type-A CPM cast with filler-A has greater values of the above parameters except density and ionic conductivity than those of type-B and C CPMs. The water uptake of type-A, B and C composite membranes was respectively in the range of 220.42–534.70, 59.64–41.65, and 15.94–2.62%. Ion exchange capacity of type-A, B and C CPMs was in the range of 3.669 × 107–2.156 × 107, 5.948 × 107–1.258 × 107, and 1.454 × 107–1.201 × 107 m.eq.g−1 respectively while the conductivity order was type-A < B < C. These types of CPMs may be helpful in many applications including proton exchange membranes, fuel cell like devices, as sensors for different metals, gas purification, water treatment, and battery separators.