Abstract
The utilization of biochar composites, produced from available and cheap materials for the remediation of the environment has been intensely studied in recently.. In this study, engineered biochar (EB) constituting plantain pseudo stem and snail shells of varying mass ratio were each co-pyrolyzed at three temperatures: 500, 600, and 700 oC in N2 gas at a flow rate of 0.2 ml/minute and a residence time of 2 hours, with the temperature ramped at 10 oC/minute. The resulting EB were characterized to determine their surface functions, chemical composition, and morphology (ultimate, Fourier transform infrared, proximate, X-Ray diffraction, X-ray fluorescence, proximate analysis ) for possible use as soil improvement agents and for water treatment. The PPS and SS biochar were also synthesized and characterized at the composites' lower and upper limit temperatures as controls. The yields of the biochar with higher compositions of SS were higher than the BC of lower SS composition, similarly, the yield of PPS at 500 and 700 oC were 56.27% and 24.42% lower than that of SS biochar at these temperatures. The characterization of the EBs showed little disparity in the surface properties of the EB of different mix ratios, but their chemical compositions were greatly affected. The hydrogen-carbon H/C ratio which is a measure of the stability ranged between 0.02 and 0.06 for all the biochar samples. The XRD results indicated the presence of mineral-like quartz, sylvite, calcite and aragonite, with the peaks becoming less intense and fewer at higher temperatures. The field applicability of the different EB for the adsorption of multi-pollutants showed a 100% efficiency for the removal of Cr and Pb, more than 80% for Ba and Cu, and an average of 60% for BTEX and phenol on the EBs.

Key words: Engineered biochar; mass ratio; co-pyrolysis; soil improvement; water treatment