Band 62, Heft 5

A laboratory study of 97 participants, designed to simulate home laundry conditions, was conducted to investigate the effect of dosing aid size on detergent usage. Each participant used two differently sized dosing aids when dosing their usual detergent. Participants used an average of 75.7 ml of detergent across both dosing aid conditions, which was approximately 15 % below the recommended amount. On average, the amount dosed with the large dosing aid was 16 % higher than with the small one, corresponding to a mean difference of 11.1 ml. This relative increase was more pronounced among younger users (18–29 years), who dosed 23 % more with the large aid compared to the small one, while older participants showed an increase of only 12 %. Surprisingly, even when instructed to load 7 kg-capacity machines, participants loaded on average only (3.4 ± 0.9) kg in a cotton program. This confirms earlier findings that perceived fullness often diverges from technical capacity. Since dosing aids are no longer included with most detergent packages, the findings highlight the continued relevance of dosing tools and the persistent mismatch between consumer behavior and manufacturer recommendations.

Detergents are water-soluble chemical cleaning agents that are commonly used in both domestic and industrial settings. They enter agricultural soils via household wastewater, greywater reuse and runoff, or occasionally through direct application for pest control. Containing surfactants, builders and chemical additives, detergents can alter soil properties and hinder plant growth. This study examined the impact of detergent-contaminated irrigation water on okra ( Abelmoschus esculentus L. Moench) over a 12-week period. Germination studies were conducted in Petri dishes, while pot experiments were performed in a screen house, using detergent solutions at concentrations of (0.0 (control), 1.0, 2.5 and 5.0) g l −1 . Detergent exposure significantly reduced seed germination at all concentrations. Key growth parameters, including shoot height, leaf number, leaf area and chlorophyll content, decreased with increasing detergent levels. Flowering was delayed by up to one week at 5.0 g l −1 and both fresh and dry fruit weights were significantly lower (p < 0.05) in detergent-treated plants. Soils irrigated with detergents exhibited an elevated pH level, increased electrical conductivity and cation exchange capacity, as well as elevated nitrogen and phosphorus levels. These findings reveal that even low concentrations of detergent can disrupt plant growth and degrade soil health. The study highlights the need for public awareness and improved wastewater management to safeguard agricultural productivity and environmental integrity.

Iron is essential for industry and the economy. It is used in construction, transport, and manufacturing. However, its extraction remains challenging due to geological complexity. Iron ore is tightly interlocked with silica, which limits the efficiency of conventional beneficiation methods. This study investigated the upgrading of the Um Nar Banded Iron Formation using froth flotation, including micro-scale tube and column flotation. Both anionic and cationic reverse flotation routes were explored. It was found that using anionic reverse flotation is more effective than cationic reverse flotation for upgrading the Um Nar Banded Iron Formation (BIF). Under optimal conditions (i.e. collector type: oleic acid, dosage: 1 kg t −1 ; calcium oxide dosage: 0.25 kg t −1 (as activator); pH 11; and starch dosage: 0.75 kg t −1 (as depressant)), a concentrate with 58 % total Fe grade, 71 % total Fe recovery, and 10.75 % SiO 2 was produced at superficial air flow rate of 2.00 cm s −1 , which was attributed to the intricate mineralogy of the ore. To overcome the limits of flotation, the study used reduction roasting with biomass sawdust as a green reductant. After roasting, a low-intensity wet magnetic separation was applied. This two-step process yielded improved results, achieving a Fe grade of 59.55 %, a Fe recovery of 78 % and a SiO 2 content of 5 % in the concentrate, rendering it suitable for processing complex iron ores.

Exploring amidopropyl betaines with high interfacial activity and low cost is highly desired but remains a daunting challenge for modern oilfields enhancing quality and efficiency. Herein, a cost-effective surfactant (ROB-HM) with high interfacial activity and oil-washing capability was successfully synthesized through formaldehyde modification strategy. The effects of formaldehyde molar ratio, catalyst dosage, reaction temperature and time were investigated, and the optimal reaction conditions were determined. The compound was characterized by mass spectrometry and Fourier transform infrared spectroscopy, and the interfacial tension, surface tension, apparent viscosity, critical micelle concentration (CMC), wettability, emulsification capacity and oil recovery rate were comprehensively evaluated. Compared to its performance before modification, ROB-HM shows significantly higher interfacial activity at low concentrations, which can be attributed to the efficient arrangement of the introduced methanol group surfactant molecules. Additionally, the CMC of ROB-HM is considerably lower than before modification, having more opportunities to form micelles. Meanwhile, the other oil-washing capabilities of ROB-HM also shows desirable results. This work paves a novel route for designing and modifying molecular structures to increase the polarity group of surfactants and affect the surface interface activity, which are suitable for enhanced oilfield recovery.

A fracturing fluid system composed of an acrylamide (AM)/2-acrylamide-2-methylpropanesulfonic acid (AMPS) copolymer and lithium magnesium silicate (LMS) nanoparticles was prepared, and its rheological properties were studied systematically. The experimental results showed that the presence of LMS increased the viscosity of the fracturing fluid, especially at high temperatures. Frequency sweep results demonstrated that the AM/AMPS copolymer fracturing fluid exhibited typical gel characteristics when LMS was introduced. The gel strength reached the maximum at an LMS concentration of 2.5 wt% and an AM/AMPS copolymer concentration of 0.6 wt%. Following continuous shear at a shear rate of 100 s −1 for 30 min at 120 °C, the viscosity of the fracturing fluid remained at 325 mPa s. This is significantly higher than the required viscosity of 50 mPa s for a high-temperature-resistant hydraulic fracturing fluid in the industry. The AM/AMPS-LMS system exhibited positive thixotropy and an excellent proppant carrying capacity both at room temperature and at 90 °C. Due to electrostatic attraction, LMS acts as an effective cross-linker between polymer chains, enhancing the rheological properties of the system. Our results showed that the AM/AMPS-LMS system is an ideal candidate for a high-temperature-resistant fracturing fluid.

Pyrrolidine surfactants are environmentally friendly compounds that exhibit good surface activity and have a wide range of applications. In this study, two monomeric pyrrolidinium surfactants (1-methyl-1-hexadecylpyrrolidin-1-ium bromide and 1-methyl-1-octadecylpyrrolidin-1-ium bromide) were synthesized and characterized by 1 H NMR, 13 C NMR, ESI MS, FTIR and TGA. Furthermore, the conductivity, density, viscosity, and surface tension of the synthesized surfactants were studied at four temperatures ((i.e. 288.15, 298.15, 308.15, and 318.15) K) using distilled water as the solvent. The conductivity results comfirmed that these surfactants are weak electrolytes. The strong interactions between the surfactant and the solvent molecules were confirmed by the constant values obtained from the density (A and B using Root equation) and the viscosity ( V ‾ $\overline{V}$ using the Einstein equation and M and K using the Moulik equation) data. The surface tension parameters such as the critical micelle concentration (CMC), surface excess concentration ( τ max ), minimum area adsorbed ( A min ) and adsorption efficiency (pC 20 ) confirmed that these surfactants are good candidates for lowering the surface tension. Thermogravimetric analysis (TGA) revealed that the compounds are thermally stable at 663.15 K with an activation energy for thermal decomposition in the range of (28.27–26.14) kJ mol −1 . Additionally, the antimicrobial action of both pyrrolidinium monomeric surfactants has been confirmed.