Investigation of Extraction and Collection of Polycyclic Aromatic Hydrocarbons from Aqueous Solutions at Different Temperatures

A Review on Modification Methods of Adsorbents for Naphthalene in Environment

Naphthalene is one of the most hazardous polycyclic aromatic hydrocarbons to public health. This paper comprehensively summarized the recent development of modification methods of adsorbents for naphthalene removal in the environment. Various modification methods used in the adsorbent were summarized, mainly including acid oxidation modification, salt modification, doping modification, amino modification, microwave modification, and plasma modification. These methods enhance the adsorption performance of naphthalene mainly by changing the pore size and the oxygen content on the surface of the adsorbent. The modification parameters and their effects on naphthalene removal as well as the advantages and disadvantages of each method are described in detail. This review provides the necessary inspiration and guidance for the researchers who develop polycyclic aromatic hydrocarbons adsorption materials in the environment.

Application of multivariate analysis on naphthalene adsorption in aqueous solutions

Naphthalene (NAP) is found as a pollutant in water, soil, and air, and adsorption is the most prominent removal process of this compound, among the methods studied. A study concerning the types of adsorbents and the parameters with the greatest influence on the adsorption process is interesting to direct future works on new adsorbents. The use of multivariate data analysis tools becomes an appealing way to compile data obtained from bibliographic reviews and to establish a behavior in NAP adsorption. This work aims to evaluate the parameters with greater influence on NAP adsorption process regarding adsorption capacity (qe_exp) with the principal component analysis (PCA), and to group common NAP adsorbents by chemical characteristics through hierarchical cluster analysis (HCA). The variables qe_exp, S, [NAP]₀, T, CT, and [Ads] were used to perform PCA with correlation matrix. For the HCA, the variables S, [NAP]₀, T, CT, and [Ads] with average linkage method (UPGMA) and Euclidean distance were used. Through PCA, it is possible to infer that S and [NAP]₀ are the factors with greater influence in qe_exp of NAP, while T, CT, and [Ads] have little correlation. PCA also shows that activated charcoal is the adsorbent with higher qe_exp. HCA grouped the adsorbents into four groups by their chemical classes, except group A. Both PCA and HCA methods show themselves as potential tools to evaluate a data set of NAP adsorption processes.