12/02/2024


The purification efficiency of the contaminants in the process of photocatalysis is influenced by the co-function of catalytic activity of materials, aquatic environment conditions and characteristics of transmission light. Here, tetracycline hydrochloride (TC-HCl) was introduced as the target pollutant, and the effects of different depths and TC-HCl concentrations on the transmission light intensity and spectral distribution were explored. The results show that incident light decreases with the increase of depth and pollutant concentration. The increase of depth influences the irradiance greatly, however, increase of concentration mainly lead to the narrow of transmission spectral range in the underwater field. The coupling relationship among pollutants, transmission spectral characteristics and photocatalytic reaction efficiency was discussed. Results show that the reduction of the underwater spectral range will reduce the effective response area of the material significantly, which directly leads to the reduction of pollutant removal efficiency in the degradation process. Aiming at different aquatic environment, photocatalytic materials with appropriate response spectral range should be selected to improve the light absorption ability, so that the removal efficiency can be improved significantly.Natural occurring metal-tolerant microbial population have replaced conventional expensive metal remediation approach since the last few years. The present study focuses on investigating the potential of a copper-tolerant plant growth promoting rhizobacterial strain Brevundimonas diminuta MYS6 for Cu bioremediation, plant growth promotion and Cu uptake in Helianthus annuus L. Box-Behnken Design of response surface methodology optimized the influencing parameters such as pH, temperature and Cu concentration. At optimized conditions of pH (5), temperature (32.5 °C) and Cu concentration (250 mg/L), the rhizobacteria followed a sigmoid growth curve pattern with maximum Cu removal of 94.8% in the stationary phase of growth. Cu exposed Brevundimonas diminuta MYS6 produced increased EPS (18.6%), indicating their role in internal defence against Cu stress. The FTIR analysis suggested the role of carboxylic acids, alcohols and aliphatic amine groups in Cu bioremoval. Furthermore, the results of pot experiments conducted with Helianthus annuus L. var. CO4 and Brevundimonas diminuta MYS6 showed enhanced plant growth and Cu uptake. The rhizobacteria increased root and shoot length, fresh and dry plant biomass and leaf chlorophyll by 1.5, 1.7, 9.9, 15.8 and 2.1 fold. The plant biomass mediate enhanced Cu uptake in roots and shoots was found to be 2.98 and 4.1 folds higher when compared to non-inoculated treatment. Henceforth the results of the study evidence the rhizobacterial strain Brevundimonas diminuta MYS6 as an efficient bio-inoculant for copper remediation.Application of activated peroxymonosulfate (PMS) to generate sulfate radical or hydroxyl radical is a promising strategy for wastewater treatment, while our knowledge on the background reaction, namely, the direct interaction between PMS and target contaminants is quite limited. In this contribution, the degradation kinetics, stoichiometry, products and mechanism of the reaction between unactivated PMS and trimethoprim (TMP), one of the most commonly detected micro-pollutants in the aquatic system were investigated systematically. The results indicated that TMP was susceptible to degradation by direct PMS oxidation via a non-radical process. By recording the decay of two reactants simultaneously, the stoichiometric ratio between PMS and TMP was estimated to be approximately 1. Higher PMS levels exhibited a promotion effect on PMS decay. And the degradation was pH-dependent, basic conditions were favorable for TMP degradation, which could be well modeled based on the species-specific reactions. The two amine groups on the pyrimidine ring were identified as the reactive sites. After direct attacks by PMS, they would be oxidized to form hydroxylamine-products, namely, N8-OH-TMP and N9-OH-TMP. These two hydroxylamine-products were quite stable and resistant to further oxidation by PMS, preventing the formation of more toxic nitroso- and nitro-products. The new findings in the present work would provide beneficial information on the strategy choice for the elimination of specific pollutants, like TMP, as PMS also exhibits relatively high reactivity towards them.The interfacial tracer test (ITT) conducted via aqueous miscible-displacement column experiments is one of a few methods available to measure air-water interfacial areas for porous media. The primary objective of this study was to examine the robustness of air-water interfacial area measurements obtained with interfacial tracer tests, and to examine the overall validity of the method. The potential occurrence and impact of surfactant-induced flow was investigated, as was measurement replication. The column and the effluent samples were weighed during the tests to monitor for potential changes in water saturation and flux. Minimal changes in water saturation and flux were observed for experiments wherein steady flow conditions were maintained using a vacuum-chamber system. The air-water interfacial areas measured with the miscible-displacement method completely matched interfacial areas measured with methods that are not influenced by surfactant-induced flow. https://www.selleckchem.com/products/PD-98059.html This successful benchmarking was observed for all three media tested, and over a range of saturations. A mathematical model explicitly accounting for nonlinear and rate-limited adsorption of surfactant at the solid-water and air-water interfaces as well as the influence of changes in surface tension on matric potentials and flow was used to simulate the tracer tests. The independently-predicted simulations provided excellent matches to the measured data, and revealed that the use of the vacuum system minimized the occurrence of surfactant-induced flow and its associated effects. These results in total unequivocally demonstrate that the miscible-displacement ITT method produced accurate and robust measurements of air-water interfacial area under the extant conditions.