Pyrolytic Temperature Dependent and Ash Catalyzed Formation of Sludge Char with Ultra-High Adsorption to 1-Naphthol

Abstract

Massively produced sewage sludge brings a serious problem to environment. Pyrolysis is a promising and bifunctional technology to dispose the sewage sludge and recover energy, in which a large amount of pyrolytic sludge char is also produced. In this study, we proposed a value-added utilization of sludge char. We prepared an adsorbent with ultrahigh capacity for hydrophobic organic pollutant (1-naphthol) by pyrolysis of sludge and removal of the ash moiety from the sludge char. The adsorptive behavior of the adsorbent is strongly dependent on the pyrolytic temperature of sludge, and the maximum adsorption capacity of 666 mg g(-1) was achieved at 800 °C, which is comparable to deliberately modified graphene. Further exploration indicated that the robust adsorption to 1-naphthol is attributed to the catalytic effect of ash in sludge which facilitated the formation of more orderly graphitic structures and aromaticity at high pyrolytic temperatures.

Application of biochar-based materials in environmental remediation: from multi-level structures to specific devices

“…In addition, the sorption rates also exhibited a transitional process: from fast to slow and then to fast due to the changes of the organic components from aliphatic to aromatic (Chen et al 2012b). With regards to the inorganic components, it was found that ash has a catalytic effect on the formation of biochar with more orderly graphitic structures in the pyrolysis process; in addition, deashing after pyrolysis increased the hydrophobic sorption sites which favored the sorption of hydrophobic organic contaminants (Liu et al 2016;Sun et al 2013). For acidic SO 2 removal, the inorganic fractions like CaCO 3 and Ca 3 (PO 4 ) 2 in biochar can transform sorbed SO 2 into new inorganic precipitations (Xu et al 2016).…”

The role of biochar properties in influencing the sorption and desorption of Pb(II), Cd(II) and As(III) in aqueous solution

“…have a strong effect on their sorptive capacities (Jiang & Wang, 2016;Fang et al, 2013;Xiao et al, 2014).…”

Influence of Pyrolytic Biochar on Settleability and Denitrification of Activated Sludge Process

“…For instance, Oleszczuk et al [9] dosed biochar into activated sludge and found that biochar decreased the phytotoxicity of sludge and positively affected seed germination. In addition, the variations of sludge properties caused by biochar addition may facilitate the separation and post-treatment of excess sludge by improving sludge settling property and increasing the heating value of dehydrated sludge [10,11]. Although the investigations on the improvement of sludge settling property by addition of activated carbon have been reported [2,12], the improvement of settleability of sludge by biochar addition has not been found.…”