In the first part of this two-stage study, the optimum conditions for one-step AC production from miswak with zinc chloride were examined using the Taguchi optimization method. Impregnation time (1–3 h), impregnation ratio (1:1–3:1), activation temperature (350–650 °C), and activation time (1–2 h) were selected as experimental parameters, and each parameter was examined at three levels. The AC produced under optimum conditions (impregnation time: 3 h, impregnation ratio: 3/1, activation temperature: 650 °C, and activation time 1 h) has a high surface area of 1702 m²/g. The characterization of AC produced under optimum conditions has been elucidated by advanced analytical methods such as SEM, FTIR, BET, and pH_pzc. In the second part, the methylene blue removal performance of OAC was investigated with a series of batch adsorption experiments. The effects of pH (2–10), initial dye concentration (500–1500 mg/L), adsorbent dosage (0.5–3.5 g/L), and temperature (25–55 °C) on the methylene blue removal efficiency were examined. The adsorption data were applied to isotherm (Langmuir, Freundlich, and Temkin) and kinetics models (pseudo-first order, pseudo-second-order, Elovich, and intra-particle diffusion). The isotherm and kinetics models that best represented the adsorption of methylene blue by OAC were the Langmuir isotherm and the pseudo-second-order kinetic model, respectively.

This study focused on determining the optimum conditions for the maximum recovery of base and precious metals from printed circuit boards of end-of-life desktop computer motherboards using Taguchi-based grey relation analysis. In the first stage of the two-stage study, optimum conditions were investigated for the dissolution of base metals (copper and zinc) in waste printed circuit boards under high-pressure leaching. The dissolution of base metals was performed based on the L25 orthogonal array designed by Taguchi method. In the second step, designed according to Taguchi L9 orthogonal array to recover gold and silver from the solid remaining from the pressure-leaching process. Optimum combinations of parameters in both stages were determined using the multi-criteria optimization technique grey relationship analysis. In the experiments carried out in the determined optimum combinations, 99.62% of copper, 98.76% of zinc, 99.15 of silver and 85.82% of gold in waste printed circuit boards were recovered. Graphical Abstract

Kızılcık meyvesinin ( Cornus mas L.) kuruma kinetiği ve C vitamin bozulması üzerine hava sıcaklığı ve hava hızının etkileri bir sıcak hava-konvektif kurutucu kullanılarak incelendi. Deneyler 50, 60, 70ºC hava sıcaklığı ve 0,4, 0,7 ve 1,0 m/s hava hızlarında gerçekleştirildi. Artan hava sıcaklığı ve hava hızında daha kısa kuruma süreleri elde edildi. Kızılcığın kuruma kinetiğini belirlemek için on iki ince tabaka kuruma modeli kullanıldı. Modifiye Henderson ve Pabis modeli en uygun model olarak bulundu. Kızılcığın C vitamin bozulması %42-54 aralığında belirlendi.