BACKGROUND Zeolite NaP1 with high crystalline intensity and good shape has been synthesized by utilizing rice husk ash. Several factors related to the formation of zeolite, such as mixing ratios, aging time, and reaction time, were investigated. Furthermore, the potential phosphate adsorption of the optimal synthesized zeolite was evaluated. RESULTS Under the optimal conditions (SiO2/Al2O3 molar ratio = 4.0, NaOH concentration = 1.5 M, aging time = 12 h, and reaction time = 8 h), the surface area and pore diameter of the zeolite NaP1 obtained were 50 m2 g−1 and 40.77 Å, respectively. By varying the aging and reaction times, zeolite NaP1 with different surface areas could be created. Specifically, reducing the aging time and reaction time result in zeolite NaP1 with a lower surface area. The adsorption efficiency and adsorption capacity of the optimal synthesized zeolite NaP1 were 38.67% and 19.97 mg g−1, respectively, at pH 6.0, with an initial phosphate concentration of 100 mg L−1, an adsorbent dosage of 2 g L−1, and a contact time of 120 min. The data are well described under the Temkin and Redlich‐Peterson models, with the correlation coefficients of 0.991 and 0.995, respectively. The maximum adsorption capacity of the Langmuir model reached 19.053 mg g−1. CONCLUSION The main contribution of this work is the direct use of rice husk ash without pretreatment to generate high crystalline zeolite NaP1 in a shorter time. The phosphate ion removal efficiency by zeolite NaP1 may be further improved by functionalizing zeolite surfaces and expanding its other applications. © 2023 Society of Chemical Industry (SCI).

Objective: To develop a simple and accurate HPLC-DAD method for simultaneous determination, the content of major components: limonin, evodiamine, and rutaecarpine in Evodiae fructus and evaluation the quality of Evodiae fructus sold in markets. Methods: Open column chromatography was used to separate and purify rutaecarpine and evodiamine, the two major alkaloids from Evodiae fructus extract as a laboratory standard. Chromatographic separation was achieved using a Germini C18 column (150 mm × 4.6 mm I.D., 5 µm), detected at 210 nm. The mobile phase consisted of acetonitrile (A), methanol (B), and water (C). The validated method simultaneously determined alkaloid content in 40 batches of samples collected from markets in different regions of Vietnam. Results: In one-step purification, our method yielded 326 mg of rutaecarpine and 128 mg of evodiamine from 3.2 g of crude extract, with purities of 98.9 and 98.5%, respectively. The structures of these compounds were identified using 1H NMR and 13C NMR. There was a significant correlation between alkaloid content and fruit size, with a Spearman correlation coefficient of>0.5 (p<0.001), and there was a large difference in alkaloid contents between three maturity degrees of the fruit. Open-mouth fruits and fruits with average sizes of 4 to 6 mm had the highest alkaloid contents, whereas closed-mouth fruits had the lowest. Conclusion: This study provided information on the standardization and quality control of evodiamine and rutaecarpine in Evodiae fructus, as well as a foundation for further pharmacological and toxicological studies.