Volume 62, Issue 6

The influence of sodium lauryl sulfate (SLS) micelles on the kinetics of Ag(I)-assisted oxidation of l -Leucine (L-Leu) by acidic Mn(VII) has been explored within aqueous environments. The advancement of the reaction is evaluated through the quantification of reduction in absorption value, utilizing the pseudo-first-order situation as a metric for [SLS], [Ag(I)], [L-Leu], ionic strength, [Mn(VII)], and [H + ]. Throughout the investigated concentration spectrum, the reaction exhibits fractional-second-order reliance on [H + ], first-order dependence on [Mn(VII)], and fractional-first-order dependency on [L-Leu] and Ag(I). Ag(I) markedly enhances the oxidation rate by a factor of 3.4. The kinetic profile revealed a 2.8-fold improvement in the rate constant associated with a rise in surfactant content. The combined action of Ag(I) and SLS micelles results in a 9.6-fold augmentation in the oxidation rate of L-Leu. The oxidation process is accelerated by the electrostatic interaction that occurs among the Mn(VII) and negatively charged micelle, which brings the oxidant closer to the substrate (L-Leu), which is normally soluble in a micellar milieu. A plausible mechanistic scheme that aligns with the kinetic observations has been highlighted, along with an examination of the Piszkiewicz model, to further explain the evident catalytic effect of SLS micellar surroundings.

This study presents findings from three Life Cycle Assessment (LCA) studies conducted in European markets, conformant with ISO 14040/44 standards, to evaluate the environmental footprints of automatic dishwashing (ADW), hand dishwashing (HDW), and laundry detergents. The primary objectives were to identify key impact areas and compare current consumer practices with more sustainable product usage. Across all product categories, the in-use phase has the largest environmental impact, with global warming potential (a proxy for carbon footprint) averaging 77 % for ADW detergents, 93 % for HDW detergents and 61 % for laundry detergents. This impact is strongly associated with the energy required to heat water, which is influenced by each country’s energy mix i.e., fossil fuels, renewable sources, or nuclear power. Sustainable usage practices, such as reducing wash temperatures and employing energy-efficient cycles in both dishwashing and laundry, present significant potential for lowering the environmental impact of these common household tasks. Future scenarios for laundry products indicate that, despite the projected greening of the electricity grid by 2025 and 2030, the in-use phase will remain the primary driver of environmental impact. The findings underscore the need for a holistic approach to assessing environmental impacts, with emphasis placed on reducing the in-use phase via the promotion of sustainable consumer behaviors through education and innovation.

The construction industry urgently needs sustainable solutions for recycling Construction and Demolition Waste (CDW). This study investigates the synergistic effects of Ordinary Portland Cement (OPC) and Polycarboxylate Ether (PCE) superplasticizer on the compressive strength of CDW-based bricks. Results of using the PCE polymer alone indicated that the polymer alone does not affect the strength significantly, whereas the strength reached 0.32 MPa using 5 % PCE. Evaluation of mixtures with 0–50 % OPC and 0–10 % PCE, reveals that 3 % PCE combined with 30 % OPC yielded the highest compressive strength (11.2 MPa) – nearly double that of OPC alone (5.95 MPa). Mechanistic studies, including zeta potential analysis and UV-VIS dispersion testing, demonstrated that PCE enhances particle dispersion via electrostatic repulsion (−25 mV charge) and steric hindrance, optimizing hydration. These bricks meet strength requirements for lean-mix concrete (LMC) and structural fills, offering a viable path for sustainable construction.

As a newly developed amphiphilic copolymer, poly (N-vinylpyrrolidone -co -methacrylic acid) (P(NVP- co -MAA)) has excellent lubricity and can be potentially employed in household detergents, personal cleaning and care. In this study, the interactions between P(NVP- co -MAA) and five different surfactants were investigated using the surface tension method. The results show that P(NVP- co -MAA) can interact with the two anionic surfactants which respectively contain COO − and SO 3 2− groups. In contrast, P(NVP- co -MAA) can’t interact with zwitterionic and cationic surfactants. The further study indicates that the electrostatic attraction between P(NVP- co -MAA) and the anionic surfactants benefits the formation of the mixed aggregation. However, as the surfactants contain quaternary ammonium groups, the electrostatic repulsion, steric hindrance and high interaction energy may hinder the binding of P(NVP- co -MAA) and these surfactants. Finally, the effect of NaCl on P(NVP- co -MAA)-anionic surfactant mixtures was studied. In the case that the surfactant has the SO 3 2− group, the addition of NaCl at the concentration not exceeding 0.5 g L −1 helps the formation of P(NVP- co -MAA)- surfactant aggregation. However, when the hydrophilic group of the surfactant is substituted by the COO − group, the addition of NaCl regardless of concentration inhibits the interaction of P(NVP- co -MAA) and the surfactants. This study offers a new guideline to select appropriate surfactants for P(NVP- co -MAA)-containing formulations.