The effect of temperature and pH on adsorption-desorption of fungicide hexaconazole was studied in two Malaysian soil types; namely clay loam and sandy loam. The adsorption-desorption experiment was conducted using the batch equilibration technique and the residues of hexaconazole were analysed using the GC-ECD. The results showed that the adsorption-desorption isotherms of hexaconazole can be described with Freundlich equation. The Freundlich sorption coefficient (Kd) values were positively correlated to the clay and organic matter content in the soils. Hexaconazole attained the equilibrium phase within 24 h in both soil types studied. The adsorption coefficient (Kd) values obtained for clay loam soil and sandy loam soil were 2.54 mL/g and 2.27 mL/g, respectively, indicating that hexaconazole was weakly sorbed onto the soils due to the low organic content of the soils. Regarding thermodynamic parameters, the Gibb’s free energy change (ΔG) analysis showed that hexaconazole adsorption onto soil was spontaneous and exothermic, plus it exhibited positive hysteresis. A strong correlation was observed between the adsorption of hexaconazole and pH of the soil solution. However, temperature was found to have no effect on the adsorption of hexaconazole onto the soils; for the range tested.

Anthropogenic activities with increasing population lead the pollution of ecosystems. Over one-third of the world's water resources are utilized for agricultural, domestic, and industrial activities, resulting in contamination by synthetic, and geogenic compounds such as dyes, fertilizers, pesticides, and heavy metals. Among these pollutants, dyes are particularly noteworthy due to their extensive use across various sectors, making them one of the leading contributors to water pollution. For this reason, dyes are one of the most important pollutants that cause water pollution. Therefore, the adsorption of Bromophenol blue (BPB) was studied in this study. Firstly, PGMA gels were produced by polymerizing of glycidyl methacrylate (GMA) monomer. Secondly, the PGMA gels were modified to prepare the new adsorbents for the adsorption of BPB dye. Thirdly, the adsorption of BPB dye was carried out. The batch adsorption method was used. The optimum adsorbent amount, initial BPB concentration, pH, and temperature parameters for PGMA gels were determined. The adsorption mechanism between modified PGMA gels, and BPB dye was elucidated by Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin isotherm models. As a result, it was seen that modified PGMA gels showed good performance in the adsorption of BPB.

This study investigates the adsorption and desorption capacities of corn cob biochars produced at three different pyrolysis temperatures. Adsorption experiments were conducted using ammonium (NH4+) and nitrate (NO3-) solutions at concentrations 5, 10, 25, 50, and 100 mg L-1. Results indicated that CC300 biochar exhibited the highest NH4+ adsorption efficiency at lower concentrations, adsorbing 88.67% of NH4+ at 5 mg L-1. However, its adsorption capacity decreased with increasing NH4+ concentration. CC400 biochar demonstrated a balanced adsorption capacity for both NH4+ and NO3-, with 83.71% NH4+ adsorption and 87.17% NO3- adsorption at 5 mg L-1. CC500 biochar showed the highest NO3- adsorption capacity, reaching 90.05% at 5 mg L-1, but was less effective in NH4+ adsorption, particularly at lower concentrations. Desorption analysis revealed that CC300 and CC500 biochars retained NH4+ and NO3- effectively, with relatively low desorption rates. In contrast, CC400 biochar exhibited higher desorption rates, indicating a controlled nutrient release potential. The study highlights the significant influence of pyrolysis temperature on the adsorption and desorption characteristics of biochar and its suitability for specific nutrient management applications. These findings contribute to the optimization of biochar production and its effective utilization in sustainable agriculture and environmental protection.

In this research, it was aimed to determine the adsorption, saturation reaching and desorption effects of ammonium, which is one of the parameters that should be kept in control for aquarium life, by clinoptilolite type zeolite which is a natural filtration material. In the aquarium water, Z1: 20 mg/l TAN and Z2: 40 mg/l TAN concentrations were determined to have adsorption up to Z1: 10 mg/l TAN and Z2: 24 mg/l TAN concentration at the end of the experiment period. After this phase, where zeolites had reached saturation, desorption system was created, and 2 groups were formed with 5-liter research aquariums and 3 repetitions. During the five-days test, water parameters were determined daily and at the same time of day (10.00). At the beginning of the experiment, mean values of 0.4 ± 0.00 mg / l TAN in Z1 and Z2 groups were determined at the end of the experiment as 1.55 ± 0.176 mg/l (15.5%) and 2.153 ± 0.27 mg/l (13.5%) TAN in Z1 and Z2 groups, respectively. When the data obtained in this study were evaluated, zeolite was determined to make desorption periodically in proportion with the amount of retained ammonium, when it reached the saturation. In intensive aquaculture systems or aquarium conditions, recondition of zeolite for necessary periods is recommended to be performed by considering these data.

The effect of temperature and pH on adsorption-desorption of fungicide hexaconazole was studied in two Malaysian soil types; namely clay loam and sandy loam. The adsorption-desorption experiment was conducted using the batch equilibration technique and the residues of hexaconazole were analysed using the GC-ECD. The results showed that the adsorption-desorption isotherms of hexaconazole can be described with Freundlich equation. The Freundlich sorption coefficient (Kd) values were positively correlated to the clay and organic matter content in the soils. Hexaconazole attained the equilibrium phase within 24 h in both soil types studied. The adsorption coefficient (Kd) values obtained for clay loam soil and sandy loam soil were 2.54 mL/g and 2.27 mL/g, respectively, indicating that hexaconazole was weakly sorbed onto the soils due to the low organic content of the soils. Regarding thermodynamic parameters, the Gibb’s free energy change (ΔG) analysis showed that hexaconazole adsorption onto soil was spontaneous and exothermic, plus it exhibited positive hysteresis. A strong correlation was observed between the adsorption of hexaconazole and pH of the soil solution. However, temperature was found to have no effect on the adsorption of hexaconazole onto the soils; for the range tested.