Recovery of rhodium from glacial acetic acid manufacturing effluent using cellulose-based sorbent

Rhodium (Rh) is a rare and highly demanded metal in metallurgy, making its efficient recovery from waste streams essential. However, there is a lack of detailed studies on the recovery of Rh from acidic waste effluents using biosorbents. This study aims to extract Rh-III from acidic effluents using dithiocarbamate-modified cellulose (DMC) as a biosorbent, and subsequently recover the extracted Rh in its elemental form (Rh-0). The parameters affecting the Rh-III extractability of DMC, such as solution pH, acid concentration, Cl- ion concentration, contact time, and sorption capacity at different temperatures, were optimized. The sorption kinetics of Rh-III onto DMC was best fitted to the pseudo-second-order (PSO) model, the equilibrium sorption isotherm data fitted well with the Langmuir model. DMC had a maximum sorption capacity of 2.57 mmol g(-1), which is substantially higher than that reported in previous studies. Waste effluent (Rh-containing glacial acetic acid) obtained from the acetic acid manufacturing industry was used to assess the applicability of DMC in capturing Rh-III from a real sample. DMC was capable of sorbing approximately 90 % of Rh-III from the real sample of Rh-containing glacial acidic acid. The sorbed Rh-III was recovered in elemental form (Rh-0) by incineration of Rh-III-loaded DMC, yielding >99 %. The sorption of Rh-III onto DMC followed a chemisorption mechanism that was confirmed by sorption experiments, Fourier-transform infrared spectroscopy (FTIR), and X-ray absorption spectroscopy (XAS) analyses. This study demonstrates the applicability of DMC in the efficient recovery of Rh from waste streams.

Automated summary

In this study, rhodium (Rh) was efficiently extracted and recovered from acidic waste effluents using dithiocarbamate-modified cellulose (DMC) as a biosorbent. The optimized parameters for Rh-III extractability of DMC were determined, and the sorption capacity of DMC was found to be substantially higher than previous studies. The applicability of DMC in capturing Rh-III from a real sample was demonstrated, and the sorbed Rh-III was successfully recovered in its elemental form (Rh-0) through incineration of Rh-III-loaded DMC.