A novel adsorbent, Y/CS/MFA composite was successfully prepared by doping a very small amount of chitosan (CS) and Y(III) ions onto the acid-modified fly ash (named as MFA), and characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) and N₂ gas adsorption/desorption technique. The adsorption property and mechanism of Y/CS/MFA for Direct green 6 (DG 6) removal from aqueous solution were investigated by carrying out batch adsorption experiments. We found that the adsorption of DG 6 on Y/CS/MFA rapidly reached equilibrium within 60 min and could be efficiently removed in a wide range of pH. The adsorption process followed the pseudo-second-order kinetic model well and was chiefly controlled by intraparticle diffusion. The equilibrium data was analyzed through three isothermal models, and it was shown that the Langmuir model could accurately describe adsorption behavior of DG 6, and the saturated adsorption capacity could reach 627 mg/g. The results of mean sorption energy from Dubinin–Radushkevich (D–R) model and FTIR analysis revealed that the adsorption should be the double properties of physisorption and chemisorption. Thermodynamics research indicated that the adsorption reaction was of feasible, spontaneous and exothermic nature. The dye-adsorbed Y/CS/MFA can be effectively desorbed by sodium hydroxide solution and recycled. The adsorption capacity of DG 6 on Y/CS/MFA was about 12 times higher than that on fly ash (FA). Y/CS/MFA composite based on solid waste fly ash would be a promising adsorbent with low cost and superior adsorption properties for high-concentration direct dye removal from wastewater.

通过将少量的壳聚糖（CS）和Y（III）离子掺杂到酸改性的粉煤灰（称为MFA）上，成功制备了新型吸附剂Y / CS / MFA复合物，并通过扫描电子显微镜对其进行了表征（ SEM），能量色散光谱（EDS），X射线衍射（XRD），傅立叶变换红外（FTIR）和N ₂气体吸附/解吸技术。通过分批吸附实验研究了Y / CS / MFA对水溶液中直接绿6（DG 6）去除的吸附性能和机理。我们发现DG 6在Y / CS / MFA上的吸附在60分钟内迅速达到平衡，并且可以在很宽的pH范围内有效去除。吸附过程遵循伪二级动力学模型，主要受颗粒内扩散控制。通过三个等温模型对平衡数据进行了分析，结果表明，Langmuir模型可以准确地描述DG 6的吸附行为，饱和吸附容量可以达到627 mg / g。Dubinin–Radushkevich（D–R）模型和FTIR分析的平均吸附能结果表明，吸附应该是物理吸附和化学吸附的双重性质。热力学研究表明，该吸附反应具有可行性，自发性和放热性。染料吸附的Y / CS / MFA可以被氢氧化钠溶液有效地解吸并循环使用。DG 6在Y / CS / MFA上的吸附能力比在飞灰（FA）上高约12倍。基于固体粉煤灰的Y / CS / MFA复合材料将是一种有前途的吸附剂，具有低成本和优异的吸附性能，可用于高浓度直接从废水中去除染料。染料吸附的Y / CS / MFA可以被氢氧化钠溶液有效地解吸并循环使用。DG 6在Y / CS / MFA上的吸附能力比在飞灰（FA）上高约12倍。基于固体粉煤灰的Y / CS / MFA复合材料将是一种有前途的吸附剂，具有低成本和优异的吸附性能，可用于高浓度直接从废水中去除染料。染料吸附的Y / CS / MFA可以被氢氧化钠溶液有效地解吸并循环使用。DG 6在Y / CS / MFA上的吸附能力比在飞灰（FA）上高约12倍。基于固体粉煤灰的Y / CS / MFA复合材料将是一种有前途的吸附剂，具有低成本和优异的吸附性能，可用于高浓度直接从废水中去除染料。