Abstract:
Sustainable lignocellulosic spent waste rice straw (SWRS) from bioethanol production
inventively applied in this study to valorize petroleum production produced water (PPPW).
SWRS expressed efficient pollutant removal over a wide range of petroleum concentration,
temperature, pH, salinity, and mixing rate reaching approximately 217 mg/g, within four hours
contact time. Kinetic studies revealed a pseudo-second-order chemisorption process with a
boundary layer control and 16.97 kJ/mol activation energy where the intra-particle diffusion was
not the only rate regulatory step. Thermodynamic studies revealed spontaneous, favorable, and
endothermic adsorption, with a strong affinity between the SWRS and oil molecules. Biosorption
mechanism studies proved the enrollment of SWRS components’ lignin, cellulose, and
hemicellulose in the oil uptake with the predominance of chemisorption over physisorption onto
the rough and highly porous SWRS surface. A single-stage batch biosorption process was
designed based on the best fitted Langmuir adsorption isotherm and applied on a real PPPW
sample. The Egyptian standard limits for safe industrial effluents discharge into marine
environment with a concomitant decrease in scale formation precursors were achieved recommending its safe reuse for enhanced oil recovery. Finally, for accomplishing zero-waste,
SWRS disposed of PPPW treatment substantiated valorized solid biofuel with a sufficient
calorific value 38.56 MJ/kg.
