Surface decoration and characterization of solar driven biochar for the removal of toxic aromatic pollutant

Abstract

BACKGROUND: In the current work, the conventional pyrolysis technique was replaced by new concentrated solar power (CSP) driven technique to fabricate and modify biochar (BC) for more sustainable, energy independent, cost-effective, and ecofriendly pyrolysis processes. Double-glazed vacuum tube was used as a reactor for pyrolysis along with solar tracking system on CSP plant, meanwhile nitrogen flow was maintained during pyrolysis to create an inert environment. Further, a novel approach was used to modifying BC by loading bimetal oxide (Mn-Ferrite) on pristine biochar (P-BC) using pre- and post-treatment to enhance its sorption capacity for anionic aromatic pollutant i.e., Eriochromie Black T (EBT) dye from aqueous solution. RESULTS: Ferric chloride hexahydrate (FeCl3·6H2O) and Ferrous sulfate heptahydrate (FeSo4·7H2O) were used to develop magnetic nanoparticles (MNPs) γ-Fe2O3 by co-precipitation technique. Both Biomass and P-BC were treated with MnCl2·4H2O and MNPs to fabricate an innovative bi-metal oxide (MnFe2O4) biochar. The characterization of modified biochars via Elemental analyzer, SEM (scanning-electron-microscopy), BET (Brunauer–Emmet–Teller), XPS (X-ray-photoelectron-spectroscopy), FTIR (Fourier-transform-infrared-spectra), and VSM (Vibrating-sample-magnetometer), ensured the loading of magnetic bimetal oxide over P-BC. Various kinetic and isotherm models were employed from which pseudo-second-order have proven to be the best fit kinetic model on all types of BCs with highest correlation coefficient value (R2 = 0.999). While among isotherm models, Langmuir demonstrated best regression coefficient (R2 = 0.98) and Qmax for EBT was up to 121.95 mg·g−1. CONCLUSIONS: Altogether, the results indicated that innovative Mn-ferrite loaded BC has better sorption ability to EBT than simple metal oxide of Mn and Fe. © 2021 Society of Chemical Industry (SCI).