Partial pyrolysis of olive wood to improve its sorption of chlorophenols and nitrophenols

Abstract

Partial pyrolysis alters the chemical and textural properties of the lignocellulosic material. This work reports the effect of partial pyrolysis of olive wood on adsorption isotherms, kinetics and thermodynamics of chloro and nitrophenols. Shape of adsorption isotherms of the partially pyrolyzed sorbents was L3 for phenol; L2 for 2-nitrophenol and 2,4-dinitrophenol; H3 for 2-chlorophenol, 3-chlorophenol and 4-nitrophenol; and H2 for 4-chlorophenol. The pyrolyzed olive wood sorbents obeyed Langmuir and Freundlich models. Pyrolysis raised adsorption capacity, favorability and spontaneity; the adsorption became more exothermic; the randomness decreased. The adsorption was mainly physical; it occurred first by film diffusion then by pore-filling. Adsorption followed second-order rate kinetics. Adsorption of phenols on olive wood seemed to be governed by hydrophobic interaction. Washing the pyrolyzed olive wood with ethanol caused a decrease in adsorption capacity, favorability and spontaneity, and the adsorption became less exothermic. This indicated that pyrolysis produced species on the olive wood surface that played a significant role in phenols adsorption.

Adsorption of P-Nitrophenol Onto Partially Reduced Graphene Oxide: An Experimental and Theoretical Study

“…Thus, the removal of p-NP from contaminated water has become an important issue in water purification as well as control of environmental contamination. So far, several techniques have been reported for removal of p-NP such as photocatalysis [2], molecular-imprinted approaches [3], biodegradation [4] and physical adsorption approaches [5][6][7][8]. Due to its low cost, high efficiency and convenient operation, the physical adsorption technique is that most widely used among the above techniques.…”

Facile Synthesis of Hydrophobic Loofah‐Chitin Aerogel for Efficient Removal of Benzene and Toluene

“…The positive Δ G values showed that the reaction rates decreased with increasing temperatures [22] . The negative Δ H values indicated that adsorption was an exothermic process, and the adsorption capacity decreased with increasing temperatures [23] . For physical adsorption, the adsorption process was a generally exothermic reaction, i. e., the temperature increase was not conducive to the adsorption.…”

“…[22] The negative ΔH values indicated that adsorption was an exothermic process, and the adsorption capacity decreased with increasing temperatures. [23] For physical adsorption, the adsorption process was a generally exothermic reaction, i. e., the temperature increase was not conducive to the adsorption. ΔS < 0 indicated that the adsorption of the benzene and toluene molecules on the MLCA surface changed from a random and a disordered step to a regular step.…”