RSC sustainability最新文献

Cementitious construction materials like concrete stand as pivotal constituents in the respective industry owing to their wide-ranging benefits in terms of abundant raw material sources, ease of processing, versatile usability, exceptional material properties, durability, and cost-effectiveness. Nonetheless, the production of cement is associated with substantial carbon dioxide (CO₂) emissions, thereby contributing significantly to global greenhouse gas levels. This conundrum underscores the pressing need for innovative solutions that can mitigate the environmental impact while preserving the indispensable attributes of cementitious construction materials. This review article delves into the realm of surface treatments as a promising avenue to augment the service life and sustainability of concrete structures. The primary objective of using coating technologies is to curtail the overconsumption of cement and natural resources – such as water, sand, and gravel – by extending the longevity of cementitious construction materials, which contributes to an alleviation in the environmental footprint of cement production and, subsequently, to a reduction in global anthropogenic CO₂ emissions. In this comprehensive study, we discuss three distinct types of established surface coating: (1) organic coatings, (2) coatings based on nanomaterials like graphene, and (3) inorganic coatings. Through a systematic examination of these approaches, we elucidate their mechanisms of protection, highlighting their potential to enhance the durability, resistance to environmental stressors, and overall performance of cementitious construction materials. Based on a comprehensive literature review, we compare the performance of these surface treatments in terms of protecting different cementitious surfaces against different degradation scenarios. Finally, we give an outlook on new innovative approaches for the protection of cementitious surfaces, including the presentation of the concept of incorporating rare earth metal ions into the surface of cementitious construction materials. This could potentially combine the advantages of organic and inorganic surface treatments as well as integral waterproofing.

Supercapacitive studies were performed on two composites of reduced graphene oxide (rGO)/β-Co(OH)₂ of the same weight composition, with the difference among them being the graphite source, one being the graphite recovered from spent Li-ion batteries (GC150) and the other being the pristine graphite (GPGC150). Results show that GC150 exhibits superior energy storage performances compared to GPGC150. However, the rate capability of the GPGC150 was found to be higher than that of GC150. Both the composites exhibited better cyclic stabilities up to 10 000 cycles at a current density of 10 A g⁻¹. GC150 exhibited zero deterioration while GPGC150 exhibited 9.23% of deterioration. The energy storage parameters, viz., specific capacitance, specific capacity, specific energy, specific power, and coulombic efficiency, exhibited by GC150 at a current density of 1 A g⁻¹ are 36 F g⁻¹, 43 C g⁻¹, 7.16 W h kg⁻¹, 0.77 kW kg⁻¹, and 94.99%, respectively, in a symmetric two-electrode system. The rGO/β-Co(OH)₂ composites synthesized using recovered graphite as the source for rGO (GC150) exhibit supercapacitance better than their analog that is synthesized using pristine graphite as the source for rGO by the synthetic route followed in the present study.

The UK zero-emissions vehicle (ZEV) mandate aims for battery electric vehicles (BEVs) to account for 100% of new sales by 2035. This study presents a fleet-scale life cycle assessment model of UK light duty vehicles through 2050, integrating a dynamic material flow analysis to evaluate the implications on critical battery materials. Rapid uptake of BEVs is projected to grow demand for primary materials within 15 years, particularly for lithium, nickel, and cobalt, exceeding current UK consumption by at least five-fold. In the longer-term, the successful creation of a closed-loop battery recycling ecosystem has the potential to mitigate further increases in demand for primary critical materials. With the adoption of efficient closed-loop, domestic recycling practice, the EU's regulations for battery recycled content requirements could be met for nickel and lithium, though cobalt remains a challenge as the recycled content targets could only be met two to three years later. The ZEV mandate is projected to be effective in reducing overall life cycle GHG emissions by 57% in 2050, relative to 2021. Even with an ambitious target like the UK's 2035 ZEV mandate, internal combustion engine vehicles will continue to operate on the road for years to come given that the fleet average is a 15 years vehicle lifetime. Thus, it is prudent to also consider low-carbon fuels as a complementary strategy to deliver the UK's net-zero target.

LiMn_xFe_1−xPO₄ (LMFP) has emerged as a promising cathode material for Li-ion batteries due to its lower cost, better sustainability, and improved thermal and cycling stabilities compared to layered oxide cathodes. The incorporation of Mn in LMFP increases the operating voltage, and therefore the theoretical energy density, compared to LiFePO₄. However, with high Mn content, it is difficult to fully utilize the Mn^2+/3+ redox due to sluggish kinetics, resulting in a lower practical capacity. Atomic-scale mixing of Mn and Fe is crucial for the optimal electrochemical performance of LMFP, yet the practical scalability and the ease of synthesizing precursor compositions with different Mn contents through co-precipitation reaction remains underexplored. We present here for LMFP manufacturing a novel, scalable precursor (Mn, Fe)₅(PO₄)₂(HPO₄)₂·4H₂O, which is air-stable and is synthesized without the use of ammonia, for the first time. The role of the reactants, pH, and temperature in controlling the phase purity and morphology of the precursor are explored. Particularly, it is found that phase purity is highly sensitive to the Mn : Fe ratio and temperature during co-precipitation. The LMFP cathodes synthesized with the precursor exhibit excellent cycling stability, retaining over 95% capacity after 150 cycles at a C/3 rate. However, while higher Mn content (>60%) increases the average voltage, the specific capacity decreases due to sluggish kinetics, limiting the benefit to energy density. This work presents an industrially scalable method to synthesize mixed precursors for LMFP cathodes with a wide range of Mn contents providing a pathway to fine-tune the Mn content and particle morphology for optimal electrochemical performance.

This study reports on converting waste into an activated carbon material for the efficient removal of diazinon pesticide (DP). The asphalt waste obtained from the streets was converted into an activated carbon and was experimentally examined in a batch system. The prepared carbon adsorbents were characterized by energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and Brunauer–Emmett–Teller (BET) analysis. The results revealed that the activated carbon (AC) had an amorphous structure, high porosity, and a relatively high surface area of 788.33 m² g⁻¹. Additionally, functional groups such as –CH₂– and SO were detected for the prepared adsorbent. The impact of DP sorption parameters, such as, sorbent dosage, initial concentration, and pH were modelled and optimized using central composite design (CCD) via response surface methodology (RSM). The optimal conditions obtained from the CCD were found to be 5.6, 30 mg, and 200 mg L⁻¹ for pH, sorbent dosage, and initial pesticide concentration, respectively, with adsorption capacity of 234.25 mg g⁻¹. The experimental data was fitted to the linear form of pseudo first (PFO) and second order (PSO) kinetic models and the data was well described by PSO kinetic models. Based on the thermodynamic parameters, the negative values of Gibbs free energy underscore the spontaneity of the adsorption process. Enthalpy change of 1.9037 kJ mol⁻¹ indicated the endothermic nature, while entropy change of 0.01751 kJ mol⁻¹ K⁻¹ indicated increased disorderliness at the adsorbent–solution interface. The study contributes to sustainable, economical solutions for pesticide contamination, emphasizing the potential of ACs derived from abundant waste materials.

The apparel industry widely uses polyurethane coated fabrics for their durability, comfort, style, and versatility. Due to the presence of multiple layers of polymers, recycling such fabrics results in low efficiency and poor yield; thus predominantly they are disposed of in landfills, resulting in severe environmental pollution. Herein we achieved a remarkably precise separation of the polyurethane (PU) coating as a neat film from the polyethylene terephthalate (PET) fabric through a surfactant-aided alkali treatment of the adhesive at room temperature. Furthermore, the dye from the fabric was continuously extracted through Soxhlet extraction resulting in 93% dye removal from the material. The PET fabric as obtained was hydrolyzed through an alkaline hydrolysis procedure with a maximum terephthalic acid (TPA) yield above 80% and purity above 90%. Dye removal from the fabric proved to be a crucial step in recycling PET fabrics as we found a notable reduction in the purity and yield of dyed PET fabrics. This work is the first to study the delamination of polymer coatings as neat films from PET fabrics commonly used in the apparel industry. It will provide useful insight and direction for recycling other such polymer-coated PET fabrics.

The oxidation of 5-(hydroxymethyl)-furfural (HMF), a platform chemical of biogenic origin, to 2,5-furandicarboxylic acid (FDCA) is a reaction of high relevance for sustainable production of polymers like polyethylene furanoate. However, a majority of the oxidation processes published to date rely on alkaline conditions, in which the instability of HMF and a resource intensive separation of FDCA are major obstacles for technological realization. In this study, we present the electrochemical oxidation of HMF in non-alkaline acetate and phosphate buffers (pH 5–7) on CoOOH modified electrodes. Current-controlled batch experiments were performed, to obtain optimal conditions with respect to the catalyst loading, current density and reaction temperature. Under optimized conditions, a FDCA yield of 94.7% in the acetate buffer (pH 5) was achieved. Through interval sampling, we were able to observe a consecutive oxidation mechanism during the optimized reaction, which mainly proceeded via the intermediate products 2,5-diformylfuran (DFF) and 5-formyl-2-furancarboxylic acid (FFCA). Furthermore, we observed that humic substances formed during the first reaction steps could also be oxidized to FDCA towards the end of the reaction.

Biomass energy stands at the forefront of remedial strategies for the current energy deficit and has garnered considerable attention. The deployment of highly efficient catalysts is pivotal to the success of this energy form. Prevailing literature established that high-valent metal presence contributed significantly to the hydrogenation of furfural to prepare 2-methylfuran. In this study, we elucidated the efficacy of a monometallic catalyst consisting solely of cobalt and its oxides, denoted as Co/CoO_x, in the catalytic transformation of furfural derived from lignocellulosic biomass into 2-methylfuran. Leveraging the economical Co/CoO_x catalyst, in conjunction with minimal addition of hydroquinone, we accomplished the selective hydrodeoxygenation of furfural, culminating in an augmented yield of 2-MF up to 73%. This investigation is the inaugural confirmation that minuscule quantities of hydroquinone can efficaciously mitigate side reactions such as the polymerization of furfural within the selective hydrodeoxygenation process. The Co/CoO_x catalyst was characterized through an array of analytical techniques, including XRD, H₂-TPR and N₂-adsorption. These characterization studies unveiled that the optimal selectivity for 2-methylfuran was achieved when the ratio of Co⁰ : Co²⁺ in the catalyst approached approximately 95%.

Industrial bleaching of shellac with sodium hypochlorite causes bleaching damages, such as double bond chlorination. Peroxodicarbonate, generated from the anodic oxidation of carbonates, acts as peroxide source for a novel acetonitrile mediated bleaching protocol, applicable on shellac. Only 6 and 9 mmol g_shellac⁻¹ of peroxodicarbonate and acetonitrile, respectively, is required to bleach shellac at room temperature with a bleaching efficiency of 94% and an acid value of 109. Furthermore, this method was demonstrated on unprocessed seedlac where the ionic strength of the peroxodicarbonate buffer facilitates dewaxing. A decreased aldehyde and acetal quantity, as well as ester hydrolysis are the major bleaching damages, visualised by FT-IR and NMR spectroscopy.

Photoelectrodes of TiO₂ in the form of films are commonly fabricated using screen printing techniques, employing viscous commercial TiO₂ pastes. However, these pastes comprise environmentally unfriendly, multicomponent formulations designed to manufacture the photoactive TiO₂ nanoparticles. To strive for sustainable processing and pave the way for the use of liquid-phase film processing technologies, the inherent limited water dispersibility of TiO₂ nanoparticles must be overcome. In this study, we show that cellulose nanocrystals, produced via an environmentally benign one-pot hydrolysis process, enable the preparation of stable TiO₂ water dispersions. The remarkable stability of these dispersions, evidenced by their outstanding ξ-potential values of −34 mV, facilitates the fabrication of macroporous TiO₂ photoactive films throughout spray coating. Employed as photoanodes in a photoelectrochemical cell, our TiO₂ photoanodes are compared with conventional TiO₂ electrodes obtained from commercial pastes under water splitting conditions. Interestingly, our photoanodes reveal a remarkable three-fold enhancement of the photocurrent performance (132 vs. 46 μA cm⁻²) and a four-fold increase in the on–off response rate (4 vs. 1 s). These findings underscore the valuable role of cellulose nanocrystals as a green processing asset for achieving TiO₂ water dispersions. Moreover, they serve as sacrificial adjuvants for preparing highly macroporous and functional film photoelectrodes, representing a significant step forward in the pursuit of sustainable and efficient materials processing.