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Caking remains a problem for the fertilizer industry in Thailand, especially for NPK fertilizers (15‐7‐18 and 18‐4‐5), leading to difficulty in application. In this work, we developed new water‐based anticaking agents to obtain high anticaking performance using response surface methodology (RSM) with Box–Behnken Design (BBD). Nineteen chemical substances were screened and effects of three independent variables (polymer, surfactant, and solvent contents) were investigated. The practicability of the model validated through analysis of variance (ANOVA) and experiments were compared. Anticaking performance of the coatings was validated using our designed‐accelerated caking method, expressed as the percentage of decrease in caking (%DC). Crushing strength and SEM/EDS analysis were used to evaluate the mechanical property and elemental composition of the coated fertilizers, respectively. The results suggested that different optimal compositions were required for different fertilizer formulas. In addition, only surfactant had a positive effect on caking prevention. The optimized anticaking coatings for 15‐7‐18 and 18‐4‐5 showed excellent performance with 92.0 %DC and 98.8 %DC, respectively. [ABSTRACT FROM AUTHOR]

The addition of synthetic corrosion and scale inhibitors in a recirculating cooling water system is a well-known method to defeat corrosion and scale problems. In this work, we utilize the extract from cassava leaf, which is agricultural waste in Thailand as a green inhibitor. Corrosion inhibition efficiency with using cassava leaf extract (CLE) for mild carbon steel was investigated in a simulated cooling water solution under both stagnant and hydrodynamic conditions. A mock-up of a recirculating cooling water system was custom-built to imitate the hydrodynamic conditions used in industry. Effects of CLE concentration (0, 50, 100, 200, 400, 600, and 800 ppm) and temperature (35 °C, 45 °C, and 55 °C) on corrosion inhibition efficiency were investigated. Increasing the CLE concentration increased its inhibition efficiency. In the case of stagnant conditions, the CLE showed a corrosion inhibition efficiency of 97.4% with 800 ppm CLE at 35 °C. The CLE performed as an anodic inhibitor. A decrease in inhibition efficiency was observed when the temperature was increased. For the hydrodynamic conditions with a flow rate of 34 L min−1 at 55 °C, a corrosion inhibition efficiency of 75.7% was seen with 200 ppm CLE. A scale inhibition efficiency of the CLE was investigated at concentrations of 0, 200, 800, and 2000 ppm. A 76.1% CaCO3 scale inhibition efficiency was obtained with 2000 ppm CLE. A change in the CaCO3 morphology due to the adsorption of the CLE inhibited scale formation. [ABSTRACT FROM AUTHOR]

Purpose The aim of this work was to investigate how Andrographis paniculata (Burm.f.) Wall.ex Nees extract affected the corrosion of low-carbon (C) steel in 0.1M HCl.Design/methodology/approach The Andrographis paniculata (Burm.f.) Wall.ex Nees was extracted into distilled water at 70°C for 1 h. The corrosion inhibition efficiency of the extract was determined in 0.1M HCl using weight loss measurements, potentiodynamic polarization and electrochemical impedance spectroscopy. The effects of extract concentrations and of temperature were investigated.Findings The Andrographis paniculata (Burm.f.) Wall.ex Nees extract could inhibit the corrosion process of low-C steel in 0.1M HCl. With the extract concentration of 1 g/l, an inhibition efficiency of 96.3 per cent was obtained. The extract acted as an anodic inhibitor. The adsorption process of the extract was physisorption and it followed the Langmuir adsorption isotherm.Originality/value This paper revealed that Andrographis paniculata (Burm.f.) Wall.ex Nees cultivated in Thailand, which was extracted using a simple and environmentally friendly method, could act as a very good green corrosion inhibitor for low-C steel in 0.1M HCl solution. [ABSTRACT FROM AUTHOR]