Continuous treatment of highly concentrated tannery wastewater using novel porous composite beads: Central composite design optimization study.

This present study depicts the successful employment of fixed-bed column for total chromium removal from tannery wastewater in dynamic mode using sodium alginate-powdered marble beads (SA–Marble) as adsorbent. The SA–Marble composite beads prepared were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and Brunauer, Emmett and Teller (BET) method. The adsorption process performance of this bio-sorbent was examined in batches and columns for real effluent (tannery wastewater). After 90 min, the total chromium removal efficiency could be kept above 90% in the batch experiment. The adsorption kinetics fit better with the pseudo-second-order model, indicating the chemisorption process and the adsorption capacity of about 67.74 mg g−1 at 293 K (C0 = 7100 mg L−1) was obtained. Additionally, dynamic experiments indicate that the total chromium removal efficiency could be maintained above 90% after 120 min at 293 K and 60 min at 318 and 333 K; it's an endothermic but rapid process. The effects of two adsorption variables (Temperature and time) were investigated using central composite design (CCD), which is a subset of response surface methodology (total Cr, COD, sulfate, and total phosphorus percentage removal). This work paves a new avenue for synthesizing SA–Marble composite beads and provides an adsorption efficiency of total chromium removal from tannery wastewater. Highlights: Powder marble coated in sodium-alginate beads (SA–Marble) was prepared & characterized, A reactor with a fixed bed was employed for the dynamic removal of total Cr from tannery wastewater, A capacity of 67.74 mg g−1 at 293 K (C0=7100 mg L-1) allows 90% total Cr removal after 90mn, Pseudo-II-order model simulates well the total Cr endothermic rapid chemisorption process, COD, SO2-4, and TP good removal suggest its use as a successful tannery wastewater treatment. [ABSTRACT FROM AUTHOR]