Abstract

This study reported the desorption of adsorbed crystal violet (CV) dye on the argan nutshell (ANS) and almond shell (AS) using nitric acid (HNO₃) as a desorbing agent and their reusability to remove the CV in multiple consecutive adsorption-desorption cycles. The prepared adsorbents were characterized using FTIR and SEM analysis. Different desorbing agents (HCl, HNO₃, H₃PO₄, CH₃COOH, NaOH, H₂O, H₂O (pH = 2), and H₂O (pH = 11)) were tested to determine the best eluent. The effect of experimental parameters, such as CV-adsorbent dose (4–40 g L⁻¹), contact time (0–180 min), and HNO₃ concentration (0.01–2 M) on the desorption of the CV from CV-ANS and CV-AS was studied. The HNO₃ (0.1 M) solution was an excellent eluent for the CV desorption from CV-ANS (98.21%) and CV-AS (98.60%) using 16 g L⁻¹ of CV-adsorbent dose at 23 ± 1 °C for 60 min. The pseudo-second-order kinetic model well-exemplified experimental data. Excellent regeneration reusability of ANS and AS for the CV removal for six consecutive adsorption–desorption cycles. This study showed that argan nutshell and almond shell as low-cost adsorbents have tremendous potential for removing the CV in multiple consecutive adsorption-desorption cycles as an alternative eco-friendly process.

摘要

本研究报告了使用硝酸 (HNO ₃ ) 作为解吸剂对摩洛哥坚果壳 (ANS) 和杏仁壳 (AS) 上吸附的结晶紫 (CV) 染料的解吸，以及它们在多次连续吸附-解吸中去除 CV 的可重复使用性循环。使用 FTIR 和 SEM 分析对制备的吸附剂进行表征。测试了不同的解吸剂（HCl、HNO ₃、H ₃ PO ₄、CH ₃ COOH、NaOH、H ₂ O、H ₂ O (pH = 2) 和 H ₂ O (pH = 11)）以确定最佳洗脱液. 实验参数的影响，例如 CV 吸附剂剂量 (4–40 g L ^-1 )、接触时间 (0–180 min) 和 HNO ₃研究了 CV-ANS 和 CV-AS 解吸 CV 的浓度（0.01-2 M）。对于 CV-ANS (98.21%) 和 CV-AS (98.60%) 的 CV 解吸， HNO ₃ (0.1 M) 溶液是出色的洗脱液，使用 16 g L ^-1的 CV 吸附剂剂量在 23 ± 1 °C 60 分钟。准二级动力学模型很好地举例说明了实验数据。ANS 和 AS 具有出色的再生可重复使用性，可用于六个连续吸附-解吸循环的 CV 去除。这项研究表明，摩洛哥坚果壳和杏仁壳作为低成本吸附剂具有在多个连续吸附-解吸循环中去除 CV 的巨大潜力，作为一种替代的环保工艺。