Polycyclic Aromatic Hydrocarbon Sorption by Functionalized Humic Acids Immobilized in Micro- and Nano-Zeolites

Gabriela Robles-Mora,Lucila Valdez-Castro,Josefina Barrera-Cortés,Omar Solorza-Feria,César García-Díaz

doi:10.3390/su131810391

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are hazardous compounds originating from anthropogenic activity. Due to their carcinogenic properties for humans, several technologies have been developed for PAH removal. Sorption with natural and organic materials is currently one of the most studied due to its low cost and its environmentally friendly nature. In this work, a hybrid sorbent involving functionalized humic acids (HAs) and nano-zeolite is proposed to entrap PAHs. The use of functionalized HAs immobilized in a porous support is designed to address the instability of HAs in solution, which has been already reported. HA functionalization was carried out to increase the non-polarity of HAs and aliphatic group formation. The HAs were functionalized by esterification/etherification with alkyl halides, and their chemical changes were verified by FTIR and NMR. The sorption isotherms of the functionalized HAs in micro- and nano-zeolites were used to assess the performance of the nano-zeolites in adsorbing these HAs. The hybrid support allowed the removal of anthracene and pyrene at percentages higher than 90%; fluoranthene, of angular molecular structure, was adsorbed at 85%. PAHs are ubiquitous in the environment, and a stable sorption of them in solid matrices will allow their removal from the environment through effective and environmentally friendly methods.

Highlights

Polycyclic aromatic hydrocarbons (PAHs) are hazardous organic compounds that are ubiquitous in the environment [1]
These compounds originate from anthropogenic activity and natural processes involving the incomplete combustion of organic matter [2]
Humin Tech Pow Humus (HTPH) product were recovered at percentages of 14 ± 3%

Summary

Introduction

Polycyclic aromatic hydrocarbons (PAHs) are hazardous organic compounds that are ubiquitous in the environment [1]. These compounds originate from anthropogenic activity and natural processes involving the incomplete combustion of organic matter [2]. For PAH removal from the environment, several remediation technologies have been developed including physical, chemical, and biological methods [3,5]. Adsorption is a technology that allows pollutant removal by physical methods. It is one of the most studied in recent years due to its simplicity and because it does not generate toxic pollutants [6]. A wide variety of both natural and synthetic materials have

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