Green synthesis ultrasonic method is reported for the preparation of zinc oxide nanoparticles loaded on activated carbon (AC) derived from coffee waste. The zinc modified AC was used effectively for the elimination of malachite green (MG) from wastewater. The examined batch adsorption parameters are; initial pH (2–9), adsorbent dose (0.10–0.50 g/100 mL), mixing time (5–120 min), MG concentrations (25–300 mg/L) and temperature (298–318 K). XRD, SEM/EDS, FT-IR and TGA/DTA techniques were used to characterize the developed Zn(OH)₂-AC composite. The results demonstrated that the adsorption capacity of Zn(OH)₂-AC composite was improved with incremental of the initial dye concentration, pH, and temperature, and decreased as the Zn(OH)₂-AC composite dose was increased. The Langmuir isotherm model (${\mathit{R}}^2=0$.97) showed better conventionality than the Freundlich model (${\mathit{R}}^2=0$.80) with a maximum removal capacity of 303.03 mg/g at 318 K and pH 7.0. The kinetic results revealed that the equilibrium data well follow the pseudo-second-order model. The thermodynamic investigations indicated the spontaneous and endothermic removal of MG. The cycling test exhibited that the developed Zn(OH)₂-AC composite had virtuous repeatable adsorption/desorption performance particularly until the fourth cycle. In addition to comparatively shorter adsorption time, relatively high adsorption capacity, reasonable reuse performance, and being of cost-effective and eco-friendly of the developed Zn(OH)₂-AC composite make it economic, effective and hopeful adsorbent for cleaning MG containing wastewaters.

据报道，绿色合成超声方法用于制备负载在源自咖啡废料的活性炭（AC）上的氧化锌纳米颗粒。锌改性的AC有效地用于消除废水中的孔雀石绿（MG）。检查的批次吸附参数为；初始pH值（2–9），吸附剂剂量（0.10–0.50 g / 100 mL），混合时间（5–120分钟），MG浓度（25–300 mg / L）和温度（298–318 K）。用XRD，SEM / EDS，FT-IR和TGA / DTA技术表征了所开发的Zn（OH）₂ -AC复合材料。结果表明，随着初始染料浓度，pH和温度的增加，Zn（OH）₂ -AC复合材料的吸附能力提高，而随着Zn（OH）_2的增加而降低。-AC复合剂量增加。Langmuir等温模型（${\mathit{[R}}^2=0$.97）比Freundlich模型（。${\mathit{[R}}^2=0$.80）在318 K和pH 7.0下的最大去除量为303.03 mg / g。动力学结果表明，平衡数据很好地遵循了伪二级模型。热力学研究表明MG的自发和吸热去除。循环试验表明，所开发的Zn（OH）₂ -AC复合材料具有良好的可重复重复的吸附/解吸性能，特别是直到第四次循环为止。除了相对较短的吸附时间，相对较高的吸附容量，合理的重复使用性能以及已开发的Zn（OH）₂ -AC复合材料具有成本效益和生态友好性，使其成为经济，有效和有希望的清洁含MG的吸附剂废水。