Efficient augmentation of superparamagnetic ferrite with alum sludge as a sustainable nanoadsorbent matrix for promoting dye removal: preparation, characterization and application

Alum sludge is produced in massive amounts through the process of water-works due to the use of aluminum sulphate as a coagulant. The possibility of twining cadmium sliver ferrites named CdAgF and cadmium cupper ferrites named CdCuF fabricated by a simple co-precipitation route with alum sludge (AS) based waste is accompanied. The prepared ferrite materials are mixed in a 50 % proportions with a modified AS (AS400) and labeled as AS400F-CdCu and AS400F-CdAgand introduced as adsorbent material. The surface functionalities, structure and morphology of the prepared adsorbents are evaluated via scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Brunauer–Emmett–Teller (BET) surface area analysis. The prepared composites are applied in the removal of two types of dyes from wastewater stream as a simulated textile effluent named Synozol dyes Red K‑HL and Synozol dyes Blue K‑HL. Initially, the isotherm time is located at 1 h of contact time. Then, the adsorption parameters are investigated and the optimal operational parameters are recorded at natural pH of the aqueous effluent (7.0) and the economic adsorbent dose used is 1 g/L. the dye concentration is evaluated and the studied range (20-100 mg/L) reported that increasing the dye concentration increasing the adsorption capacity. Thermal effect has a negative behavior on the adsorption capacity. Langmuir and Freundlich isotherm models are evaluated to check the experimental data and the results are best fitted with Langmuir model for the both dyes. The greatest monolayer adsorption capacity is associated to CdAgF and its composite form AS400-CdAgF that is recorded as 149.031 and 102.564 mg/g, respectively for KHL Red dye and 79.744 and 32.414, respectively for KHL Blue dye. Also, the kinetic model is investigated and the data is following pseudo-second-order kinetic model. Finally, the recyclability of the catalyst showed its effectiveness for sustainable use.