**1. Introduction**

Nanotechnology is one of the most prominent promising technologies that offer solutions to different problems in various aspects of our life. In fact, nowadays, nanotechnology used in the synthesis of nanoparticles has attracted great interest in different applications (environment, emerging, industries…etc.) [1–3]. A healthy environment is a major challenge faced by the world today. In connection with the rapid industrialization, scientists reported the presence of more than 700 carcinogenic and highly toxic inorganic and organic micro pollutants. Toxic inorganic metals included instance chromium, mercury, cadmium, lead...etc. and inorganic oxyanions included fluoride, nitrate, phosphate etc. while organic contaminants included, phenols, dye, hydrocarbons, and pesticides. They are considered persistent environmental pollutants non-biotransformable or non-biodegradable [3]. Mining operations, metal plating facilities, textile industries, fertilizer industries and pharmaceutical industries are the most common sources of these hazardous substances [4–8]. Consequently, developing efficient techniques for the treatment of effluent fertilizers and industrial before being discharged into the environment is a considerable issue in terms of public health and environmental protection.

The need for sustainable technologies to conserve the environment leads to the development of a lot of technologies in the field of water treatment [9]. In this scenario, research efforts have been conducted to remove these contaminants from wastewater using several methods such as adsorption, electrolysis electrodialysis, ion exchange, reverse osmosis, coagulation and flocculation, and chemical precipitation have demonstrated different degrees of remediation efficiency [9–11].

Many of these methods, such as coagulation and flocculation, ion-exchange, and reverse osmosis, are expensive and cannot be applied in developing countries. Conventional coagulation methods and chemical precipitation cause secondary contaminants requiring an additional treatment and increasing the treatment cost [3, 11].

Interestingly, adsorption is the most attractive process in developing countries due to its lower cost, easy-to-use and its high efficiency to remove different types of contaminants [3, 12, 13]; thus, the adsorption method produces low quantities of sludge, which is largely produced by other methods (chemical precipitation) [3], but it requires a good choice of adsorbent. Generally, the selection of the useful adsorbent for water treatments is controlled by many factors such as the adsorption capacity of the material toward the target contaminant, cost/efficiency ratio, and the type and concentration of the contaminants present in water [3]. Ideal adsorbents must therefore meet a number of criteria, such as: (1) should be environmentally benign; (2) should demonstrate a high sorption capacity and high selectivity especially to the pollutants occurring in water at low concentration; (3) the adsorbed pollutants can be easily removed from its surface, and (4) should be recyclable [14]. A sorbent with the above characteristics would be considered an excellent adsorbent in wastewater treatment. Efficient adsorbents of biological, organic or mineral origin have been used for wastewater treatment [15, 16]. The most important used adsorbents are agricultural wastes [17], clay minerals [18, 19], modified clays [20, 21], zeolites [22], and activated carbon [23]…etc.

Nanotechnology has great potential for improving the efficiency in preventing water pollution and improving the treatment methods [9]. In fact, the application of nanotechnology in water treatment extends to various fields like nanoscale filtration techniques, adsorption of pollutants on nanoparticles and breakdown of contaminants by nanoparticle catalysis [3, 15].

Among various nanoparticles 'clay minerals' generally speaking, clay minerals which are constituted of layered mineral silicates in the nano dimension, are cheap and non- hazardous, and are characterized by high surface reactivity and stability due to their large surface area [24]. Compared with other adsorbent materials, clay minerals with physical adsorption ability and surface chemical activity, are readily available, making them increasing focus as of late [25, 26]. Nevertheless, the adsorption ability of clay is mainly dependent on fundamental traits, for instance, the charge characteristics of the adsorbent, pH, competing ions and pollutant type [18]. Moreover, clays that exhibit the crystal structure and negative charge have restricted their application [27]. In order to overcome these limitations, many studies in recent years have addressed the improvement of the mechanical properties of clay through the use of various types of modifications [21].

Recently, there has been an increasing interest in using organoclay for the removal of contaminants from soil and aquatic environments due to here the large specific surface and a hydrophobic behavior. Indeed, the intercalation of cationic surfactants changes the surface properties from hydrophilic to hydrophobic, greatly increases the specific surface and increases the basal spacing resulting in exposure of more adsorption sites [28, 29], thus, adsorption capacity especially when surfactant loading *Organoclay Nano-Adsorbent: Preparation, Characterization and Applications DOI: http://dx.doi.org/10.5772/intechopen.105903*

exceeds the CEC of clay [30]. Organoclay are a group of surfactant modified clays with hydrophobic properties, which have been extensively used in remediation of heavy metals, herbicides and pesticides, organic compounds and anionic contaminants [31].

The overall aim of this chapter was the investigation of the preparation and characterization of organoclay and their capacities to remove various pollutants as well as empirical findings on the equilibrium isotherms and kinetics. The literature for the chapter included published studies on hazardous substances.
