A novel nanocomposite was synthesized by covalent functionalization of graphene oxide (GO) with 5,10,15,20‐tetrakis(4‐hydroxyphenyl)porphyrinatoiron (III) chloride (Fe−THPP) via an ester linkage. The synthesized nanocomposite was characterized by various techniques such as XPS, Raman spectroscopy, BET, IR, UV‐Visible, TGA, SEM, and EDX. The synthesized nanocomposite exhibited appreciable interaction with crystal violet (CV) dye with a detection limit of 2.6×10−6 μg/mL and binding constant of 35.93×103 ppm−1 which ensured the high concentration of CV dye on the surface of synthesized photocatalyst. The nanocomposite was effectively utilized in the photo‐degradation of CV dye under visible light irradiation. The photo‐degradation efficiency was remarkably high (93.45 %) with a low catalytic dosage of 0.4 mg/L within 80 minutes. The nanocomposite exhibited good stability and reusability and thereby can be used in the photocatalytic degradation processes to treat wastewater.

The presence of a highly toxic pyridine carboxamide insecticide, namely flonicamid in water bodies poses a serious risk to both the aquatic ecosystem and human health. Therefore, a graphene oxide (GO) decorated with azo‐functionalized calix[4]pyrrole i. e. GO‐azocalix[4]pyrrole (GACP) was synthesized to study the removal of flonicamid insecticide through adsorption. The nano‐adsorbent was characterized by IR, XPS, TGA, Raman, SEM, and TEM data. The effect of concentration of flonicamid solution, contact time, adsorbent dosage, temperature, and pH was investigated in the batch adsorption process. Experimental data suggested that equilibrium was attained within 40 min and adsorption efficiency was 93.28 %. The synergistic effect of GO and azocalix[4]pyrrole played an important role in the adsorption. The Langmuir isotherm was followed and the maximum adsorption capacity was found to be 11.43 mg/g. The pseudo‐second‐order kinetic data was well obeyed and thermodynamic investigation suggested the feasible and spontaneous nature of flonicamid onto GACP nanocomposite.