Preparation and characterization of polyethylenimine-functionalized pyroxene nanoparticles and its application in wastewater treatment

•Poly(ethylenimine)-functionalized nanopyroxene were synthesized successfully by hydrothermal technique.•The PEI-PNPs were used for adsorptive removal of dye from textile wastewater.•External mass transfer diffusion and Sips models were used for describing the adsorption.

In this study, polyethylenimine-functionalized pyroxene nanoparticles were successfully prepared in-house for the removal of commercial red dye (CRD) from an industrial wastewater. The functionalization was accomplished by anchoring polyethylenimine (PEI) onto the surface of pyroxene nanoparticles without surface modifications or preliminary coating. Characterization was followed out by textural properties, X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), infrared (IR) spectroscopy, and thermogravimetric analysis (TGA). The prepared nanoparticles were successfully functionalized by the PEI and portrayed granulated-like morphologies with average crystaline domain sizes around 10 nm and BET surface area (∼18 m2/g) that increased reasonably to ∼119 m2/g by drying using lyophilizing method instead of conventional drying of the synthesized materials. The prepared PEI-PNPs showed an excellent adsorption capacity (∼340 mg/g) and fast adsorption kinetics (<15 min) for the CRD from a textile wastewater in batch mode of adsorption compared with that of magnetite nanoparticles and a commercial activated carbon that had lower adsorption capacity of the dye (<50 mg/g). Adsorption was not influenced by the solution pH owing to the wide range of PEI buffering capacity. The adsorption kinetics and isotherms could be well delineated using the external mass transfer diffusion and the Sips models, respectively.

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