**1. Introduction**

Endocrine disrupting chemicals (EDCs) are chemical pollutants that can affect the endocrine (hormonal) system and intrude on important developmental processes in humans and wildlife (World Health Organization, 1996). EDCs include natural estrogens (estrone: E1, 17β-estradiol: E2, estriol: E3), synthesized estrogen (ethinylestradiol: EE2), and artificial composites (bisphenol A: BPA, polychlorinated biphenyls: PCBs, polybrominated biphenyls: PBBs, and dioxins). EDCs are

dichlorodiphenyltrichloroethane (DDT) from pesticides and vinclozolin from fungicides [1, 2]. Among these chemicals that are cited, BPA is produced in high volumes than the other ones and it can be found worldwide. Centers for Disease Control reported that BPA is present in the urine of 92.6% of over 2500 Americans [3, 4] and this indicates a general exposure to this chemical. Stockholm Convention has regulated the manufacturing and the utilization of DDT, PCBs, PBBs, and dioxins (Stockholm Convention on Persistent Organic Pollutants, 2009), and this agreement limited the exposition to these composites compared to BPA which is not regulated in all countries. A lot of studies reported that there was arising substantiation for adverse reproductive issues (fruitfulness, cancers, deformations) from exposure to EDCs, and there was also mounting substantiation of these chemicals on thyroid function, brain function, obesity and metabolism, and insulin and glucose homeostasis (Stockholm Convention on Persistent Organic Pollutants, 2009). Former studies reported the presence of BPA in wastewater, surface and ground waters, and indeed drinking water [5]. This urged major enterprises over endocrine-disrupting chemicals by scientists in recent years. The pollution of the environment by these chemicals is mainly via industrial activities [5]. Predominantly, it's used in the manufacturing of polycarbonate plastics and epoxy resins [6]. Also, dental securities, foods and potable barrels, polycarbonate tubes, cleansers, care products, etc., are listed as exposition sources (World Health Organization 1996). The United States Environmental Protection Agency has defined a daily dose of 50 mg of BPA/kg of body weight/day for BPA [6]. Although there is no database on BPA pollution in an aqueous environment in Burkina Faso, its presence could be supposed in wastewater, surface, and ground waters, due to numerous original factories and diligence whose products clearly lead to a general exposition of the population to BPA. The absence of legislation in many countries makes it urgent to develop simple and effective methods for BPA remediation in aqueous matrixes. Numerous procedures including adsorption, chemical advanced oxidation, membrane filtration, and electrochemical mineralization were utilized for BPA removal from water [2, 3, 7–13]. Among the listed procedures, adsorption seems to be appropriate due to its high effectiveness, ease of implementation, and low cost of the process due to the usefulness of various adsorbents. Numerous adsorbents including organo-montmorillonites [7, 8, 10–12, 14, 15], inorganic-organoclays [16], surfactant modified vermiculites [17], surfactant modified sepiolite [18], surfactant modified palygorskite [19], polymer based on kaolinite [20], chitosan [21], surfactant modified zeolite [2, 22, 23], graphene [9], etc., have been used for BPA removal from water.

Clay modification is widely done in aqueous solution via cation exchange or solidstate reactions. Organic molecules are inserted in dried clay interlayers by solid-state responses without washing with solvent and this makes the synthesis environmentally friendly and more favorable for industrialization [24]. Generally, the publication in this topic reported the organoclays synthesis using various procedures and chemicals, numerous type of clays, and diverse surfactants as reviewed elsewhere [24]. To obtain organoclays with hydrophobic properties, quaternary alkylammonium salts are the most frequently used, but n-alkyl-pyrrolidones, maleic anhydride, biomolecules, polymeric quaternary alkylammonium, alkyl-imidazolium, and phosphonium salts are also employed to the accomplishment of this outcome [24]. The field of application of organoclays is very large and this includes nanocomposites, adsorbents of organic and inorganic pollutants in soil, water, air, etc. [8, 24, 25]. Clays and organically modified clays are considerably employed in adsorption processes for the removal of organic pollutants due to their low cost and environmental friendly [3, 7, 8, 10, 21, 26].

*Solid-State Synthesis of Organoclays: Physicochemical Properties and Application… DOI: http://dx.doi.org/10.5772/intechopen.107503*

Smectites are generally utilized due to their high cation exchange capacity (CEC), swelling aptitude, and high specific surface areas leading to high adsorption/absorption capacities [3, 7, 8, 10]. From the literature, it is known that organoclays employed for BPA removal from water are synthesized by liquid-state insertion of surfactants into the clay layers [16, 21, 26]. In the present investigations, the organoclays utilized to study the BPA sorption from water have been synthesized via a solid-state insertion methodology. The synthesis occurs via solid-state intercalation reaction by using two natural local clays (denoted AH and DI) and four cationic surfactants (dodecyl trimethylammonium, n-C12H25(CH3)3N+ denoted C12; tetradecyltrimethylammonium, n-C14H29(CH3)3N<sup>+</sup> denoted C14; hexadecyltrimethylammonium, n-C16H33(CH3)3N+ denoted C16 and didodecyldimethylammonium, (n-C-12H25)2(CH3)2N<sup>+</sup> denoted 2C12).

The present work investigates: (i) the solid-state intercalation of three alkyltrimethyl-ammonium and one di-alkyldimethylammonium cation into two natural clays, and the subsequent changes in structure and physicochemical properties; (ii) the efficiency of organoclays prepared via solid-state methodology for BPA removal from water; (iii) various parameters such as kinetics (pseudo-first-order model and pseudo-second-order model), isotherm (Freundlich and Langmuir models) and thermodynamic parameters (standard enthalpy (ΔH), standard entropy (ΔS), and standard free energy (ΔG)) on BPA adsorption from water.
