Environment benign Ghee residue – titania based adsorbent for quick removal of methyl orange dye

Use of renewable waste material for water treatment is an area of interest. An attempt has been made for preparation of Dairy industry waste Ghee residue (GR) based biogenic adsorbent for removal of dye present in water/waste water. This novel approach contributes in valorisation of dairy industry by- product Ghee residue. The ghee residue was first converted into carbon and processed with the titanium precursor and rare earth metal. This combination yields GR-C/TiO₂/Eu³⁺ adsorbent. A series of adsorbing material was prepared by differing loading of Eu³⁺ keeping ratio of RG-C and TiO₂ constant. Synthesized adsorbents were subjected to characterization studies such as X-Ray Diffraction (XRD) spectroscopy, Brunauer Emmett Teller-Surface Area (BET-SA), Scanning Electron Microscopy (SEM), Fourier Transformed Infra Red spectroscopy (FTIR) etc. XRD pattern shows formation of crystalline anatase phase of TiO₂ with average particle size of 34.9494 nm. SEM image also confirms irregular morphology with particles in nanometer range. BET-surface area of GR-C/TiO₂/Eu³⁺ (1%) was found to be 53.633 m²/g with total pore volume = 8.555e^− 02 cc/g for pores smaller than 18330.1 Å (Radius) at P/Po = 0.99948 and average pore radius was found to be 3.19022e^+ 01 Å indicating mesoporosity of material. Synthesized adsorbents were studied for dye adsorption and GR-C/TiO₂/Eu³⁺ (1%) shows quick and complete removal of 5ppm Methyl orange dye in contact time of less than three minutes at 30-32^oC with the adsorbent dose of 75 mg/10mL. The high adsorption property is attributed to presence of crystalline nanostructured TiO₂ and Eu³⁺ on to the biogenic carbon framework. Langmuir adsorption isotherm data indicates monolayer adsorption with R² value of 0.97. ΔG^o values are in the range of -12.81 to -17.77 KJ mol^− 1 indicating spontaneous adsorption process.