Abstract
In this study, the efficiency of biochar (BC) produced from sugarcane bagasse at different pyrolysis temperatures (300, 400, 500 and 600 oC) for simultaneous removal of CdII, PbII, CuII, CrIII, NiII and ZnII ions from aqueous solutions was assessed. All BC were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR), 13C nuclear magnetic resonance (13C NMR) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). The effects of pyrolysis temperature, initial adsorbate concentration and adsorbent dosage on adorption capacity of BC were examined through batch experiments. The BC efficiency was also evaluated after a desorption cycle. The maximal adsorptions (CdII: 51.50%, CrIII: 74.35%, CuII: 91.18%, NiII: 47.05%, PbII: 96.17% and ZnII: 40.50%) were observed for BC produced at 500 oC, probably because of its higher porosity and presence of functional groups detected by SEM and FTIR. The maximum adsorption capacity for CdII, CrIII, CuII, NiII and ZnII (ions fitted to Langmuir model) were 175, 303, 455, 156 and 128 µg g-1, respectively. The predominance of phenolic groups observed in Py-GC-MS data may explain the high percentage of multi-element removal. Experimental data were best fitted to pseudo-second order, Sips and Freundlich models. The BC presented good removal results after a desorption cycle.
Highlights
Trace metals such as Cd, Cr, Cu, Ni, Pb and Zn are classified as significant water pollutants due to their persistence, high toxicity and tendency of bioaccumulation.[1]
The biochar yield on a dry mass basis decreased when the biomass was pyrolyzed at higher temperatures (500 and 600 °C) (Table S1, SI section) that was attributed to volatilization of organic matter.[52]
Adsorption experiments using BC produced at different temperatures showed that BC500 had the highest percentage of metal removal from an aqueous solution (CuII, CdII, CrIII, NiII, PbII and ZnII)
Summary
Trace metals such as Cd, Cr, Cu, Ni, Pb and Zn are classified as significant water pollutants due to their persistence, high toxicity and tendency of bioaccumulation.[1] they occur naturally in rocks (geogenic sources), most of contamination sources and human exposure are derived from anthropogenic activities, including agriculture, battery, mining, textile and tanning industries.[2,3,4] The rapid industrialization and urbanization are increasing the levels of these chemicals in environment, raising concerns over the impacts of these pollutants on ecosystems and human health. Ion exchange methods are known to have fast kinetics and high treatment capacity,[7] involving for instance the use of a strong acid cation-exchanger (synthetic or natural solid resin) that removes the contaminants from water.[6,7] Adsorption is a process that offers flexibility in the treatment and sometimes can be reversible, consisting
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
