Next Sustainability最新文献

Polyethylene terephthalate (PET) waste, especially originating from post-consumer bottles, represents a significant environmental hazard owing to its widespread utilization and inadequate biodegradability. Addressing the growing environmental issues associated with plastic waste, the development of sustainable strategies for recycling and utilization is of paramount importance. This study explores the potential of employing waste plastic bottles, specifically PET, as a precursor in the synthesis of Metal-Organic Frameworks (MOFs). The synthesis procedure encompasses the depolymerization of PET to yield terephthalic acid, serving as an organic linker in the formation of MOFs. An analysis of the potential applications of PET-derived MOFs, including catalysis, adsorption, and gas separation, is conducted. The review also highlights prospects and challenges within the field, underscoring the necessity for further refinement, scalability, and commercialization of PET-sourced MOFs. The overarching aim is to foster the advancement of ecologically responsible methods for waste plastic management and the creation of valuable materials through MOF synthesis.

Herein, vanadium pentoxide (V₂O₅) encapsulated Gum ghatti grafted poly(acrylamide-co- methacrylic acid) adsorbent was synthesized to remove methylene blue dye from water. The materials were characterized by FTIR, TEM, SEM, Raman and XRD analysis. Batch adsorption studies were performed on the materials. Several variables' effects on methylene blue removal, including pH, contact time, initial dye concentration, and adsorbent dosage, were examined. Kinetics and thermodynamic analysis were also carried out for the adsorbent-adsorbate interaction to determine the maximum adsorption and mechanism for adsorption. By using UV-Vis spectrophotometric analysis, the dye concentration was evaluated both before and after adsorption. Langmuir, Freundlich, and Dubini-Radushkevic's isotherm models were used to analyze the adsorption data. Results showed a maximum adsorption efficiency of 92 % at a pH of 9 and 0.2 g as the maximum adsorbent dosage. The study followed the Langmuir isotherm model with a correlation coefficient (R²) of 0.9995. The results from the kinetic studies show a pseudo-second-order mechanism. The negative values of the Gibbs free energy change ΔG° ranging from −10.57 KJmol⁻¹ to −9.64 Kmol⁻¹ within the temperatures of 298 K to 313 K is an indication of a spontaneous process. A negative enthalpy change (ΔH° = −29.05 KJmol⁻¹) shows an exothermic process and a negative entropy change (ΔS° = −0.06 KJmol⁻¹) represents a highly ordered system. ANOVA in Microsoft Excel and other statistical analyses were used to evaluate the effects of time, pH, concentration, dose, temperature, and other factors on the effectiveness of dye adsorption. Importantly, every parameter that was investigated showed statistically significant impacts on the removal of dye (p < 0.05), revealing their important impact on the adsorption process.

Sustainable hydrated lime is produced from biomass ash rich in calcium carbonate, with properties similar to industrial hydrated lime. However, there is a lack of current and relevant research on sustainability related to the use of alternative limestone, derived from waste such as biomass ash. In this sense, the present research aims to study the behavior of cementitious coating mortars with partial and total replacement of industrial hydrated lime by sustainable hydrated lime, through microstructural, macrostructural, physical and chemical tests. Microstructural analyses performed by SEM demonstrated the presence of cement hydration products (CSH and ettringite) in all mortars evaluated. Chemical analyses through XRF and XRD showed similarity in chemical composition and crystallographic phases between the mortar with industrial hydrated lime and the ecological mortars. The FTIR showed chemical bonds characteristic of cement mortars in all ecological mortars, ratified by TG/DTG, which shows the decomposition of products such as CSH, ettringite, portlandite and calcite in all ecological mortars. Through the results found, the viability of replacing sustainable hydrated lime with industrial hydrated lime in the preparation of ecological mortars stands out, at the optimum percentage of 50 %, with possible total replacement (100 %) without significant losses in resistance.

In the current investigation, WO₃ thin films are prepared via simple hydrothermal method at different pH values (1, 7 and 11). In this study, XRD, SEM, FTIR, UV–visible, and electrochemical techniques were used to study pH effects on the preparation of WO₃ and their structural, morphological, and electrochromic variations. The XRD analysis revealed that the pH of the precursor solution significantly influences crystallinity, with acidic conditions favouring high crystallinity and efficient electrochromic (EC) performance, while more alkaline conditions result in reduced crystallinity and amorphous film formation. The SEM analysis demonstrates that pH significantly influences the morphology of WO₃ films. FTIR spectroscopy exhibited characteristic peaks associated with WO₃, affirming the successful synthesis of WO₃ thin films. The electrochemical investigations demonstrated that WO₃ films prepared at a pH of 1 exhibited exceptional EC activity, characterized by the highest optical modulation density of 0.3 and a colouration efficiency (CE) of approximately 122.2 cm²/C at 633 nm. These findings underscore the promising potential of pH-controlled hydrothermal method for tailoring the electrochromic behavior of WO₃ thin films, with implications in energy efficient smart windows.

Recovery of rare earth elements from bauxite residues of lateritic versus karstic origin was explored at a pH ranging between 2.7 and 4.5 using a mixture of citric acid and citrate in water. Dissolution yields of up to 82 % for lanthanum and 62 % for yttrium were achieved with excellent selectivity toward iron (a selectivity factor of up to 4200), the main element of bauxite residues. An experimental Box-Behnken statistical design identified the concentration of citric acid/citrate and temperature as key factors controlling the dissolution yield and selectivity of rare earth elements. Observed differences in dissolution yields and selectivity as a function of origin were attributed to differences in the speciation of rare earth elements in the two bauxite residues. It is therefore possible to draw an “à la carte” graph that identified the optimum citric acid/citrate concentrations and dissolution temperatures for dissolution yields and selectivity for the two BRs. This work provides fundamental knowledge for the future development of sustainable processes for the recovery of rare earth elements from bauxite residues derived from bauxites of different origin.

Detoxification of water resources is the need of the hour and a number of environment friendly materials are proposed by scientist to deal with water pollution issues. The present study deals with preparation and characterization of porous activated carbon from golden shower pods, a waste ligno-cellulosic biomass, for the removal of dye contaminants from aqueous solution. The synthesized material, golden shower biochar (GSBC) was characterized using various analytical techniques to confirm the presence of active sites. The BET analysis of GSBC revealed high surface area of 1120 m²/g with total pore volume of 1.099 cm³/g and average pore radius 19.618 Å. Operational parameters were optimized using batch studies by taking GSBC dose of 50 mg which showed complete removal of target dyes with an initial dye concentration of 200 mg/L with just 60 min interaction time; based on these results, a fixed bed column of GSBC was designed and column studies were performed. Adsorption isotherm studies were carried out using Langmuir and Freundlich models, of which Langmuir model was found to be best-fit with maximum adsorption capacities of 208.86 mg/g, 284.35 mg/g and 327.56 mg/g for Crystal violet, Brilliant green and Methylene blue dyes respectively. Analysis of kinetics and thermodynamics revealed that the best-fit model was pseudo second-order with spontaneous reaction course and exothermic nature. Regeneration was carried out using gamma irradiation of dye loaded GSBC, followed by leaching in alcohol. It was observed that a 30 KGy dose was just sufficient to completely degrade the dye on the adsorbent surface. GSBC has shown immense potential for eradication of dyes from water effluents and it is easily recovered with negligible loss in efficacy.

The short-term power output variability of solar photovoltaic (PV) systems caused by passing clouds is becoming a major concern for grid operators. As the penetration of utility-scale PV systems boosts, the rapid power fluctuations greatly challenge the grid's transient stability. A photo voltaic system is greatly vulnerable to Partial Shading. The performance analysis of PV systems clearly suggests that the maximum power of partially shaded PV systems is inversely proportional to the heaviness of shading. However, some literatures are not of the same opinion; for them, the maximum power of a partially shaded system is invulnerable to shading heaviness, often at certain critical points. According to research on the P-V characteristic curve under various numbers of shaded modules and shading levels, the irradiance of the shaded modules reaches a certain turning point or critical point. The PV array becomes insensitive to high-level shading, categorically for the series topology. This paper presents an experimental results of performance parameters with varying shading heaviness. The experiment is performed on a Photovoltaics string of series connected modules, a 119KW grid-connected rooftop solar power plant using the Power Quality analyser for continuous recording of various parameters under changing shading heaviness. The degree or heaviness of shading decides the critical point. The critical point can vary based on the number of the shaded modules.

In the last few years, hydrogen has attracted much attention because of its importance in the transition to a sustainable energy system and its use as a raw material in many industrial processes. In this context, chemical looping is proposed as an alternative to traditional methane reforming processes, where methane is partially oxidized by the lattice oxygen of a solid oxygen carrier instead of using water or pure oxygen. This work presents a thermodynamic analysis of MnWO₄ as an oxygen carrier and the compositions at equilibrium were calculated by minimizing the total Gibbs free energy of the system. To evaluate its possible integration into a chemical looping scheme, this study assesses the optimal reaction temperature and reactant molar ratio to attain high hydrogen yield while avoiding carbon formation. The findings suggest that temperatures exceeding 775°C and ratios above stoichiometry are necessary. For successful regeneration, air or water can be used. In the former case a stoichiometric ratio of 1.5:1 of O₂ to MnO/W is required, while for the latter, an excess of water in necessary.

Hydrocarbon proton exchange membranes (PEMs) which exhibit low-cost, improved robustness, and simple synthesis relative to perfluorosulfonic acid (PFSA) membranes, are of great significance for proton exchange membrane fuel cells (PEMFCs). Herein, we report a facile and affordable preparation of sulfonated and phosphonated poly (p-terphenyl perfluorophenyl)s PEMs via superacid-catalyzed Friedel−Crafts condensation of p-terphenyl and pentafluorobenzaldehyde monomers, following by highly selective para-substitution of fluorobenzene to graft ion exchange groups. The rigid and well-defined polymer structure with precisely controlled anionic groups, enables good phase separation and efficient ionic clustering to promote proton transport. Sulfonated and phosphonated PEMs show modest proton conductivities of 150 and 120 mS cm⁻¹ at 90 °C, and achieve H₂/air PEMFC peak power densities of 360 and 237 mW cm⁻² at 80 ℃, respectively. Interestingly, we find that phosphonated PEMs have significantly higher resistance to free radicals than sulfonated PEMs. Overall, the results suggest that our prepared hydrocarbon PEMs have potential applications for fuel cells.

Miriti, derived from the leaves of the Amazon palm tree Mauritia flexuosa, is a foam-like material that can serve as a natural substitute for synthetic foams, offering the advantage of natural internal fiber reinforcement. This study assessed miriti’s mechanical properties and potential applications. With an average specific mass of 63 kg.m^–3, miriti is amongst the lightest natural solid materials. Its internal fiber reinforcement provides mechanical properties seven to 30 times higher than synthetic foams of similar density in the parallel-to-grain direction. Miriti is a green material and shows high potential for use in sandwich panel cores, thermal/acoustic applications requiring higher strength and stiffness, and load-bearing walls of small structures. Sustainable management of M. flexuosa by local communities is feasible, promoting their sustainable development. Additionally, miriti can inspire the design of synthetic foams reinforced with internal fibers.