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In this study, adsorption characteristics of a negatively charged dye, Acid Blue 25 (AB25), on pomelo pith (PP) was studied by varying the adsorption parameters, with the aim of evaluating the adsorption mechanism and establishing the role of hydrogen bonding interactions of AB25 on agricultural wastes. The kinetics, intraparticle diffusion, mechanism, and thermodynamics of the AB25 adsorption were systematically evaluated and analyzed by pseudo-first-order and pseudo-second-order kinetic models, the Weber–Morris intraparticle and Boyd mass transfer models, the Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin isotherm models, and the Van’t Hoff equation. It was found that AB25 adsorption followed pseudo-second-order kinetics, governed by a two-step pore-volume intraparticle diffusion of external mass transfer of AB25 onto the PP surface. The adsorption process occurred spontaneously. The adsorption mechanism could be explained by the Langmuir isotherm model, and the maximum adsorption capacity was estimated to be 26.9 mg g−1, which is comparable to many reported adsorbents derived from agricultural wastes. Changes in the vibrational spectra of the adsorbent before and after dye adsorption suggested that AB25 molecules are bound to the PP surface via electrostatic and hydrogen bonding interactions. The results demonstrated that the use of pomelo pith, similar to other agricultural wastes, would provide a basis to design a simple energy-saving, sustainable, and cost-effective approach to remove negatively charged synthetic dyes from wastewater.

<p>An attempt to maintain the quality and preservation of honey pineapple (<em>Ananas comosus</em>) is required to avoid fruit loss and its nutritional values. This research aimed to determine the effect of washing with ozonated water and preservation in the cold storage on the quality of honey pineapple. The research was arranged in a completely randomized design with two factors consisting of washing water (ozonated water and non-ozonated water) and storage (ozone cold storage at 2–7 ^oC and room temperature at 25–28 ^oC). Honey pineapples were observed for 35 and 20 days in ozone cold storage and at room temperature, respectively. The results showed that ozonation reduced the total bacterial count. Washing with ozonated water did not affect the glucose content of honey pineapple stored at room temperature, but affected those in cold storage. On the other hand, ozonation affected both vitamin C content and weight loss of honey pineapple stored at room temperature and in cold storage. Ozone is able to control bacterial development in honey pineapple resulted in longer shelf life compared to those without ozonation.</p>

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