have reported 98.84% of Azure B dye adsorption removal from aqueous solution by utilizing novel hybrid nanocomposite catalysts based on carbon nanotube, zinc oxide, zinc, and nickel-phosphorus metalloid. In recent times, the removal of toxic heavy metal ions from water supplies and wastewater has been a core interest for many researchers and scientists throughout the world. Heavy metals could enter and accumulate in the human body through the food and ecological chain and cause bioaccumulation, which leads to chronic health disorders such as cancer, kidney failure, liver damage, brain damage, and bone softening. Their concentration in the environment has dramatically increased to a dangerous level due to extensive industrial activities such as electroplating, anodizing-cleaning, etching, and milling. Some of the heavy metal contaminants are chromium, zinc, lead, nickel, platinum, silver, and cadmium ions. Generally, contaminants like various heavy metals and dyes exist stable in the aqueous medium, which also causes serious damage to the water ecosystem, its flora-fauna, and the environment. Large water contamination is due to the large usage of organic solvents, hazardous industrial chemicals, heavy metals, textile dyes, detergents, soaps, fertilizers, pesticides, herbicides, pathogens, and paint pigments, which all find their way into water resources. Nowadays, different toxic organic, inorganic, and microbial contaminants have been recognized at basic levels in all water resources. The quality of potable water has become increasingly sensitive worldwide and allocation of water resources is among the most critical global issues. The BMNC also showed favourable reusability for adsorbate Cr(VI) ions removal from the water solution. The kinetics of the adsorption process was found to be a pseudo-second-order model ( R 2 = 0.9912). Moreover, the adsorption of Cr(VI) onto the BMNC was found to be the best fit with Langmuir isotherm ( R 2 = 0.9984) and a maximum adsorption capacity of 98 mg/g. The results of these studies demonstrate that the BMNC performs well. Experimental design optimization results in 96.5% of Cr(VI) removal from the water solution at optimized adsorption parameters viz., adsorption time of 101 min, pH of 1.95, adsorbent dose of 1.12 g/L, and initial Cr(VI) concentration of 36.2 mg/L. The intercalation of magnetite nanoparticles onto the bentonite clay increased its specific surface area from 142 to 177 m 2/g as per BET analysis. Particle size of BMNC was in the range of 15 to 95 nm as per DLS. These adsorbents were characterized by atomic absorption spectrophotometer (AAS), Brunauer–Emmett–Teller (BET), dynamic light scattering (DLS), scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) analyses. This adsorbent was prepared by the coprecipitation method from sodium bentonite (BNa) with iron chloride solution at controlled pH and under an inert atmosphere. Bentonite-magnetite nanocomposite adsorbent (BMNC) was made and investigated for its adsorption removal of Cr(VI) from an aqueous solution.

Dynamic light scattering size range