New sulfonated covalent organic framework for highly effective As(III) removal from water.

The goal of taking out As(III) from water is to reduce the detriment that poisonous metals can do to people and nature. A substance that can absorb As(III), TFPOTDB-SO3H, was made by combining 2,5-diaminobenzenesulfonic acid and 2,4,6-tris-(4-formylphenoxy)-1,3,5-triazine in a reaction that joins molecules together. This substance can adsorb As(III) very well and has excellent qualities like being easy to use again, separate substances, and filter out liquids. At pH = 8 and at room temperature, TFPOTDB-SO3H adsorbed a lot of As(III). It achieved a removal rate of 97.1 % within 10 min and could adsorb up to 344.8 mg/g. A research was conducted to investigate the effect of co-existing anions on the elimination of arsenic. The findings indicated that the presence of anions had a minimal adverse impact, reducing As(III) uptake by approximately 1-7 %. The kinetics of the uptake process were found to be controlled by the quasi-second order kinetic model, while the Langmuir isotherm model validated that the mechanism for As(III) removal was monolayer chemisorption. According to the thermodynamic analysis, the adsorption process was endothermic and occurred spontaneously. Moreover, even after 4 successive adsorption-desorption cycles, the adsorbent preserved a substantial uptake productivity of 88.86 % for As(III). The results collectively indicate that TFPOTDB-SO3H holds considerable promise for the efficient adsorption and elimination of As(III) ions from wastewater.

Exploring the interaction between microplastics and heavy metals: unveiling the impact of microplastics on lead sorption and desorption in soil.

The global attention on microplastics in soils, particularly in agricultural soils, has been growing. However, there is a need to investigate the impact of microplastics on the ability of agricultural soils to add and remove pollutants. To address this, a series of batch experiments were conducted to examine how high-density polyethylene microplastics affect the adsorption and desorption of lead in a field soil under different conditions. The equilibrium for both lead adsorption and desorption, with and without microplastics, was reached within 120 min. The adsorption kinetics of lead followed the quasi-second-order model, and the Langmuir model provided a more accurate fit for the adsorption isotherm compared to the Freundlich model. Generally, the addition of microplastics decreased lead adsorption but increased its excretion. The effects varied depending on the dosage of microplastics, particle size, and solution pH. Higher microplastic dosage and larger particle size resulted in a more pronounced reduction in lead adsorption and an increase in lead excretion, although these effects also depended on the solution pH. Analysis using energy-dispersive X-ray spectroscopy confirmed the adsorption lead on the surface of microplastics. Both types of microplastic samples, before and after lead adsorption, exhibited similar X-ray diffraction patterns, indicating that the microplastics maintained their high crystallinity and did not undergo any new crystalline phase formation. Consequently, the introduction of microplastics into the soil may enhance the mobility of lead by reducing the soil's adsorption capacity, thereby posing greater risks to the agricultural ecosystem.

Providing an environmental management model with emphasis on ecosystem resilience: a coastal City in Southern Iran.

Urban environmental management is an effective tool which aims at urban development inline with environmental, social and economic values. The present study aims to provide an environmental management model of Bandar Abbas with an emphasis on ecosystem resilience. The research has been conducted in several steps, the first of which includes the assessment and analysis of resilience of Bandar Abbas city in terms of environmental dimensions and components based on the selection of environmental indicators and components in accordance with the opinions of urban issues experts and access to the available data and information resources, estimation and evaluation of the resilience status of indicators and components of the city. The second step presents the regression equation of resilience under the influence of environmental indicators and components. Also, the third step provides a strategy for the resilience, given the frequency of strategies ranking by the experts and the current environmental situation of Bandar Abbas. The results of the overall resilience assessment indicated that Bandar Abbas is of favorable resilience in terms of the climate, water and soil, vegetation, water, air, water quality and air quality indicators and components, while being of unfavorable resilience situation in terms of the institutional-functional index, citizens' culture and awareness, waste, sewage and trash management. In general, the environmental resilience situation of Bandar Abbas city was found to be favorable with an estimated value of 3.29 and in a good situation against environmental crises. Finally, an environmental management model has been presented along with the effective strategies from the perspective of Urban Issues experts to improve the resilience of Bandar Abbas city.

Bioavailability and concentration of heavy metals in the sediments and leaves of grey mangrove, Avicennia marina (Forsk.) Vierh, in Sirik Azini Creek, Iran.

The concentration and bioavailability of Ni, Cu, Cd, Zn, and Pb in the sediments and leaves of grey mangrove, Avicennia marina, were studied throughout Sirik Azini creek (Iran) with a view to determine heavy metals bioavailability, and two methods were used. Results show that Zn and Ni had the highest concentrations in the sediments, while Cd and Cu were found to have the lowest concentrations in the sediments. Compared to the mean concentrations of heavy metals in sedimentary rock (shales), Zn and Cu showed lower concentration, possibly indicating that the origin of these heavy metals is natural. A geo-accumulation index (Igeo) was used to determine the degree of contamination in the sediments. Igeo values for Zn, Cu, Pb, and Ni showed that there is no pollution from these metals in the study area. As heavy metal concentrations in leaves were higher than the bioavailable fraction of metals in sediments, it follows that bioconcentration factors (leaf/bioavailable sediment) for some metals were higher than 1.