Waste Iron Dust Derived Iron Oxide Nanoparticles for Efficient Adsorption of Multiple Azo Dyes
Twinkle Twinkle, Hema Tewatia, Jaidev Kaushik, Archana Sahu, Shyam Kumar Chaudhary, Sumit Kumar Sonkar
Abstract
Herein, we have described a simple and viable approach to use the waste byproduct of steel industries: red iron oxide dust (IOD) for synthesizing its reduced version as reduced-IOD (r-IOD). The r-IOD possess active multiphases of iron oxides (Fe@Fe 3 O 4 @Fe 2 O 3 ) and is used for the adsorption of three organic dyes. The surface area of magnetically active r-IOD is found to be ∼4.5 times than that of IOD and shows better mesoporosity. Due to having a larger surface area, r-IOD is used for the efficient adsorption of three organic dyes that include two anionic azo dyes, namely, RG 19 (Reactive Green 19), RO 16 (Reactive Orange 16) and one cationic MG (Malachite Green) dye, with maximum adsorption capacities of ∼2162.9, ∼2273.1, and ∼1400.2 mg g –1, respectively. Various batch experiments related to kinetics, isotherms, and adsorption thermodynamics are studied to understand the rate, order, type, and feasibility of adsorption. The effects of temperature, pH, loading, and concentration, on the adsorption process are also investigated. Moreover, the adsorption capacity of r-IOD is satisfactorily tested via an external spiking method toward the dye removal from industrial wastewater and laboratory wastewater.