Influence of pyrolysis temperature on lead immobilization by chemically modified coconut fiber-derived biochars in aqueous environments

Abstract

Biochar has received widespread attention as an eco-friendly and efficient material for immobilization of toxic heavy metals in aqueous environments. In the present study, three types of coconut fiber-derived biochars were obtained by pyrolyzing at three temperatures, i.e., 300, 500, and 700 °C. In addition, nine types of biochars were prepared by chemical modification with ammonia, hydrogen peroxide, and nitric acid, respectively, which were used to investigate changes in physico-chemical properties by inter alia, Fourier transformation infrared spectrophotometry (FTIR), scanning electron microscope (SEM), and BET specific surface area analysis. Batch sorption experiments were carried out to determine the sorption capacity of the biochars for lead (Pb) in aqueous solutions. Results showed that the cation exchange capacity of biochar pyrolyzed at 300 °C and modified with nitric acid increased threefold compared to the control. Loosely corrugated carbon surface and uneven carbon surface of the biochar pyrolyzed at 300 °C were produced during ammonia and nitric acid modifications. Removal rate of Pb by the coconut biochar pyrolyzed at 300 °C and modified with ammonia was increased from 71.8 to 99.6 % compared to the untreated biochar in aqueous solutions containing 100 mg L−1 Pb. However, chemical modification did not enhance adsorption of Pb of the biochars pyrolyzed at higher temperatures (e.g., 500 or 700 °C), indicating that resistance of biochars to chemical treatment increased with pyrolysis temperature.Electronic supplementary materialThe online version of this article (doi:10.1007/s11356-016-7428-0) contains supplementary material, which is available to authorized users.

Sustainable Conversion of Coconut Wastes into Useful Adsorbents

“…Parallel to the result they obtained using the coconut fiber adsorbent, they found out the activation with KOH does not improve the adsorbent's ability to remove elemental mercury as the adsorption capacity of char adsorbent was higher (Q ¼ 3142.57 μg/g) than that of the activated char (Q ¼ 57.77 μg/g). The finding of this study can be supported by the finding of Wu et al's where char that were produced at high pyrolysis temperature may be resistant to chemical modification [110].…”

“…On the other hand, Wu et al conducted an extensive research on coconut fiber utilization for removal of Pb(II) ions from aqueous solution [110]. In their study, the coconut fiber was carbonized at 300, 500, and 700 C and was treated with different chemicals such as H 2 O 2 , NH 4 .OH, and HNO 3 as to study its effect on Pb(II) removal.…”

Effect of advanced catalysts on tire waste pyrolysis oil

“…Pyrolysis of tire waste has been carried out using different reactors, including fixed bed reactors (de Marco et al, 2001), thermogravimetric analysis (Teng et al, 1998), spouted beds (Lopez et al, 2009), fluidized bed pyrolysis (Kaminsky and Mennerich, 2001), vacuum pyrolysis (Roy et al, 1995), and rotary kiln (Li et al, 2004). The primary objective of these studies was to investigate the effect of various process variables such as temperature, reaction time, feedstock size and type, and scale of the reactor on pyrolysis products and how to increase the quantity of produced liquid oil, but not the quality of liquid oil (Kraiem et al, 2016;Wu et al, 2016;Wan et al, 2014). For example, Cunliffe et al (1998) concluded that increase in temperature from 450 to 600 °C decreased the liquid oil yield from tire waste pyrolysis.…”

Characteristics and agrarian properties of biochar derived from pyrolysis and co-pyrolysis of rubberwood sawdust and sewage sludge for further application to soil improvement

“…Biochar with high porosity can be applied as adsorbent of heavy metals from soil, because the active sites on biochar can attract and reduce the toxic elements (Wu et al 2016;Karimi et al 2020).…”