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In this study, activated carbon from dragon fruit peel was synthesized and applied for its ability to adsorb organic pigments in water. The results obtained from the SEM and FTIR analyzes revealed the presence of the characteristic functional groups of activated carbon. The adsorption capacity of synthetic activated carbon was evaluated against methylene blue dye. This study also evaluated factors affecting the adsorption process, including time, content, temperature, concentration, and solution pH. The optimal adsorption conditions were recorded at pH 6, concentration 95 mg/L, time 43 min, and temperature 30 °C. At optimal adsorption conditions, the adsorption capacity predicted from the model is said to be 54.12 mg/g with an efficiency of 27.5%. The experimental data of the study were evaluated using adsorption kinetic models and adsorption isotherm models of the material. The results showed that the activated carbon material from dragon fruit peel is a potential material in the application for adsorbing pollutant dyes in wastewater.

To reduce the hazards brought by water hyacinth, many applications of water hyacinth have been studied and continuously expanded. The large biomass of water hyacinth is applied in many fields such as for wastewater treatment, wastewater purification, biological raw material sources, animal feed production, medicine, antioxidants, agriculture, and household appliances. This research investigates the desalination capacity of freshwater hyacinths, raw materials from water hyacinths, biochar, and activated carbon materials from water hyacinth stems. Results have shown that the suitable temperature for charring fresh water hyacinth is 420 °C. The activated carbon from the water hyacinth stems with a BET surface area of 200.4 ± 1.9 m²/g can be desalinated under the conditions of 0.4 g of activated carbon mass, 15 min of reaction time, 2.0 ppt of salt concentration, and at neutral pH. In contrast, raw materials from water hyacinths and biochar were unable to desalinate. This study evaluates the desalination ability of the activated carbon material of water hyacinth.

In the present study, the optimized solvent extraction conditions with regards to the total polyphenol content (TPC) and antioxidant capacity of rosemary leaf extract (RLE) were determined. The one-factor-at-a-time method was used to independently investigate the effect of several extraction parameters, including ethanol concentration (0–100% v/v), extraction temperature (50–80°C), extraction period (15–60 min), material–solvent ratio (1:5–1:10 g/mL), and extraction cycles (1, 2, and 3 times) on polyphenol content. Response surface methodology (RSM), in combination with a central composite design, was used to perform optimization. The following optimal conditions that gave maximal TPC were determined and experimentally verified: ethanol concentration of 65% (v/v), extraction temperature of 65°C, material–solvent ratio of 1:7.5 g/mL, extraction time of 15 min, and 2 cycles of extraction. These parameters corresponded with the TPC yield of 87.42 ± 0.25 mg gallic acid equivalent/g dried feed material (mg GAE/g DW). The optimal conditions gave a high extraction yield (337 ± 6 mg dried extract/g dried feed material) with 197.28 ± 3.11 mg GAE/g dried extract. The estimated models were strongly significant (p < 0.05) for TPC values with significant regression coefficients (R 2) of 0.9979. The obtained RLE was supposed to be the top grade of natural antioxidant with the IC50 (DPPH assays) value of 9.4 ± 0.1 μg/mL, which is higher than that of the vitamin C by just three times (IC50 = 3.2 ± 0.1 μg/mL). Current results justify RLE as a potential agent in food preservation applications.

Due to the impacts of climate change and the reduction in the flow of the Mekong River, saline intrusion into the inland has been an emergent and pressing issue. The purpose of this study is to analyze the effects of various saline conditions (0–25‰) on changes in some soil properties under laboratory conditions. Ten topsoil samples were collected from a depth of 0–20 cm in the dry seasons in the rice–corn rotation fields with low salinity, in Thanh Phu district, Ben Tre province, Vietnam. The examined criteria consisted of soil pH, soil electrical conductivity of the saturated paste extract (ECe), exchangeable Na, percentage of exchangeable Na, and content (%) of nitrogen and phosphorus. The results revealed that the pH range of soil decreased from 5.14–5.72 to 4.08–5.14 when the soil salinity increased from 0 to 25‰. At the salinity of 10‰ and higher, the available nitrogen began to decline. Meanwhile, the available phosphorus tended to decrease as the salinity increased past 12‰. Some measures are also discussed, with the aim of ensuring sustainable rice farming in the circumstances of increased salinity.

In this study, we used a synthetic aerogel based on PVA/agar/maltodextrin to remove the antibiotic ciprofloxacin (CFX) from aqueous media. Response surface method (RSM) is used to study the relationship between the factors affecting the adsorption process, thereby optimizing the adsorption efficiency, and making decisions on improving the adsorption process better sub. The research results obtained are as follows: pH2, initial CFX concentration 51 mg L-1, adsorbent dosage 0.16 g L-1, adsorption time 120 min, and temperature 51.5 °C reached the maximum adsorption capacity. The maximum additive is 38.63 mg g-1. The experimental data agree with the pseudo-quadratic kinetic model and the Langmuir and Temkin isotherm models. The composite aerogel adsorbent (AE) in this study is a potential candidate for adsorbent to remove antibiotic contamination in aqueous media. [ABSTRACT FROM AUTHOR]