Surface Modification of NiO‐Al₂O₃ Nanocomposites using Stearic Acid as a Modifier and their Applications in Self‐cleaning and Removal of Dyes

In the present study, a quick surface modification method has been developed for the modification NiO‐Al 2 O 3 nanocomposites using stearic acid (SA). The surface modification of NiO‐Al 2 O 3 nanocomposites with stearic acid was confirmed by various analytical techniques (FT‐IR spectroscopy, thermal gravimetry (TG), carbon and hydrogen (CH) and XPS). There is no change in XRD patterns, and FE‐SEM and TEM images of NiO‐Al 2 O 3 nanocomposites after modification with SA. FT‐IR analysis of SA modified NiO‐Al 2 O 3 nanocomposites shows characteristic IR bands of carboxylate group. TG and CH analyses also confirm the presence of SA in the NiO‐Al 2 O 3 nanocomposites. XPS analysis of SA modified NiO‐Al 2 O 3 nanocomposites shows the presence of carbon atoms of stearic acid. The SA modified NiO‐Al 2 O 3 nanocomposites show water contact angle greater than 90° which suggests their hydrophobic nature. The SA modified NiO‐Al 2 O 3 nanocomposites were explored for self‐cleaning and also as adsorbent for the removal of crystal violet and rhodamine B dyes from aqueous solutions. The SA modified NiO‐Al 2 O 3 nanocomposites remove the dyes within 30 minutes. The effect of various adsorption parameters (adsorbent dosage, contact time, pH, and temperature) was investigated to understand the optimum adsorption conditions. The SA modified NiO‐Al 2 O 3 nanocomposites show better self‐cleaning property as compared to unmodified NiO‐Al 2 O 3 nanocomposites.