An eco-friendly material was synthesized through interfacial polymerization of aniline on particles of g-C3N4 with arginine, resulting in Arg-PANI@g-C3N4 composite. The as-synthesized composite was characterized by the Brunauer, Emmett, and Teller (BET) surface area, X-ray energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The adsorption capability of as-synthesized composite towards Orange G (OG) dye has been evaluated under several experimental conditions, such as the adsorbent dosage, initial dye concentration, contact time under agitation, pH of dye solution and temperature. Thermodynamics parameters such as free energy (ΔG°), entropy (ΔS°), and enthalpy (ΔH°) were also calculated and suggested that the adsorption process is spontaneous and endothermic in nature. The kinetics data revealed that the adsorption of OG dye onto Arg-PANI@g-C3N4 follows the pseudo-second order kinetics model. The maximum adsorption capacity was found to be 80.54 mg·g−1. Furthermore, the Arg-PANI@g-C3N4 surface exhibited a Langmuir-like adsorption isotherm in contrast to a Freundlich isotherm due to homogeneous active site distribution. Regeneration investigation showed the excellent reusability of Arg-PANI@g-C3N4 composite during the cleaning up of solution containing OG dye molecules.

Arginine-polyaniline@g-C3N4 for outstanding retention of Orange G dye from water
    Abstract
    1 Introduction
    2 Experimental
        2.1 Material and methods
        2.2 Preparation of g-C3N4
        2.3 Elaboration of Arg-PANI@ g-C3N4 composite
        2.4 Characterization techniques
        2.5 Batch experimental
        2.6 Arg-PANI@g-C3N4 regeneration
    3 Results and discussions
        3.1 Characterization
            3.1.1 Surface morphology and EDS spectroscopy
            3.1.2 FT-IR spectroscopy
            3.1.3 XRD analysis
            3.1.4 N2 adsorptiondesorption
        3.2 Adsorption study
            3.2.1 Effect of adsorbent dosage
            3.2.2 Effect of initial pH
            3.2.3 Adsorption kinetics
            3.2.4 Adsorption equilibrium and thermodynamic study
            3.2.5 Comparison with other adsorbents
            3.2.6 Regeneration of Arg-PANI@g-C3N4 composite
    4 Conclusion
    References

• Abdallah Albourine(Laboratory of Materials and Environment, Faculty of Sciences, Ibn Zohr University, Agadir, Morocco)
• Mohamed Laabd(Laboratory of Materials and Environment, Faculty of Sciences, Ibn Zohr University, Agadir, Morocco)
• Nouh Aarab(Laboratory of Materials and Environment, Faculty of Sciences, Ibn Zohr University, Agadir, Morocco)
• Abdelghani Hsini(National Higher School of Chemistry (NHSC), University Ibn Tofail, BP. 133, 14000 Kenitra, Morocco, Laboratory of Advanced Materials and Process Engineering (LAMPE), Faculty of Science, Ibn Tofail University, BP 133, 14000 Kenitra, Morocco)
• Abdelaziz Imgharn(Laboratory of Materials and Environment, Faculty of Sciences, Ibn Zohr University, Agadir, Morocco)
• Fatima‑Zahra Mahir(Laboratory of Materials and Environment, Faculty of Sciences, Ibn Zohr University, Agadir, Morocco, Organic Chemistry and Physical Chemistry Laboratory, Faculty of Sciences, Ibn Zohr University, Agadir, Morocco)
• Hamid Zouggari(Laboratory of Materials and Environment, Faculty of Sciences, Ibn Zohr University, Agadir, Morocco)