In the present investigation, physico-chemical characterization of composite material revealed the presence of fluffy surface structure with crystalline look and negatively charged surface functional groups. The study of adsorption flux by using dimensionless numbers φ (2.62), N_k (62.68) and λ (1.17 × 10⁻⁵) proved that adsorption of nickel ions on the surface of composite material was mostly film diffusion-limited with maximum surface area coverage coupled with weakened surface tension. The results of intraparticle diffusivity and Boyd plot model showed that at the onset of process, film diffusion was the primary mechanism involved and at the later stage intraparticle diffusion played a critical role as rate governing step. The values of film (0.65 × 10⁻⁸ cm² sec⁻¹) and pore diffusivity (1.8 × 10⁻¹² cm² sec⁻¹) coefficients showed that the adsorption process is dependent upon two different types of diffusion namely film and pore diffusion. Overall, transport and reshuffling mechanism had no substantial role in adsorption dynamics of nickel ions on the surface of composite material. Sorption isotherm and kinetics modeling showed higher values of regression coefficients for Langmuir isotherm (R² = 0.99) and pseudo-second-order kinetic model (R² = 0.99) compared to other models. This showed that sorption of nickel followed monolayer coverage with chemisorption at optimized process parameters like pH 6, biosorbent dose 0.1 g/L, temperature 50 °C, agitation rate180 rpm, adsorbate concentration100 mg/L and contact time 60 minutes. The positive value of enthalpy of adsorption (ΔH = + 10.41 kJ/mole) and entropy (ΔS = +58.19 J/mol K) showed that binding of nickel ions on the surface of the composite material was endothermic with improved randomness at solid-liquid interface. The negative value of (ΔG = −6.4 to -8.67 kJ/mol) showed spontaneous nature of nickel adsorption on composite material in the liquid phase.

在本研究中，复合材料的物理化学特征表明存在具有结晶外观和​​带负电的表面官能团的蓬松表面结构。利用无因次数φ（2.62），N _k（62.68）和λ（1.17×10 ^-5）进行的吸附通量研究表明，复合材料表面镍离子的吸附主要受到膜扩散的限制，具有最大的表面积。覆盖，表面张力减弱。颗粒内扩散率和Boyd图模型的结果表明，在过程开始时，膜扩散是主要的参与机制，而在后期，颗粒内扩散作为速率控制步骤起着关键作用。胶卷值（0.65×10 ^-8cm ² sec ^-1）和孔扩散系数（1.8×10 ^-12 cm ² sec ^-1）系数表明，吸附过程取决于两种不同的扩散类型，即膜扩散和孔扩散。总体而言，转运和改组机理对复合材料表面镍离子的吸附动力学没有实质性作用。吸附等温线和动力学模型显示Langmuir等温线（R ² = 0.99）和伪二级动力学模型（R ²= 0.99）。这表明在优化的工艺参数（例如pH 6，生物吸附剂量0.1 g / L，温度50°C，搅拌速度180 rpm，吸附物浓度100 mg / L和接触时间60分钟）下，镍的吸附随后发生化学吸附的单层覆盖。吸附焓（ΔH= + 10.41 kJ / mole）和熵（ΔS= +58.19 J / mol K）的正值表明，镍离子在复合材料表面的结合是吸热的，在固液中的随机性得到改善接口。负值（ΔG= -6.4至-8.67 kJ / mol）表明镍在液相中自然吸附在复合材料上。