Abstract
Reuse of waste from Hami melon (cantaloupes) straws (HS) mingled with polypropylene (PP) ropes is necessary and beneficial to mitigate environmental pollution. The objective of this study was to investigate the characteristics and mechanisms of Cd2+ adsorption on biochars produced by co-pyrolysis of HS-PP with various mixing ratios. N2-sorption, scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), elemental analysis, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermal gravity, and differential thermal gravity (TG/DTG) were applied to evaluate the physicochemical properties of materials. Batch adsorption experiments were carried out for investigating the effects of initial pH, Cd2+ concentration, and adsorption time. It was found that the Langmuir and pseudo-second-order models fitted best for the experimental data, indicating the dominant adsorption of co-pyrolysis biochars is via monolayer adsorption. Biochar derived at 4/1 mixing ratio of HS/PP by weight percentage had the highest adsorption capacity of 108.91 mg·g−1. Based on adsorption isotherm and kinetic analysis in combined with EDS, FTIR, and XRD analysis, it was concluded that the main adsorption mechanism of co-pyrolysis biochar involved the surface adsorption, cation exchange, complexation of Cd2+ with surface functional groups, and chemical precipitation. This study also demonstrates that agricultural wastes to biochar is a sustainable way to circular economy.
Highlights
China is a large agricultural country; accompanied with agricultural production, the generation of solid waste continues to grow rapidly
The physicochemical properties and the Cd2+ adsorption capacity of co-pyrolytic biochars were affected by the addition of PP
When the PP content was 20%, the adsorption capacity of Cd2+ reached the maximum of 108.91 mg·g−1, indicating that BC20 can be used as an effective sorbent for removing Cd2+ from aqueous solutions
Summary
China is a large agricultural country; accompanied with agricultural production, the generation of solid waste continues to grow rapidly. The agricultural waste production increased with the human demand for food and other agricultural products. According to the China Statistical Yearbook, the yields of crop straw are over 750 million tons every year in China. Extensive studies have been conducted on agricultural waste management worldwide, but the total utilization rate of agricultural waste in most villages of the world is less than 30% due to poor economic returns and low environmental awareness, which is a waste of these resources [1]. As one kind of synthetic polymer materials, plastics are widely used in daily life, packaging, pharmaceutical, agriculture and electronics manufacturing industries due.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
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
