Preparation of multicomponent composites from sustainable natural materials and analyses of their dye adsorption properties

Abstract

In this study, the preparation and dye adsorption/absorption properties of novel composite hydrogels with multiple components are described. Components were selected according to certain basic criteria: Optimization of resulting composite properties, especially adsorption/absorption capacity, and also the use and production of sustainable materials in order to prevent such materials to become pollutants themselves in case of their application in large quantities. First group of composite components are cellulose derivatives that can be obtained in large quantities. This natural and valuable material is capable of adsorbing a variety of hydrophobic and hydrophilic organic chemicals and if necessary its structure can be further modified. Cellulose was shown to form well-defined composites with several types of polymers. Another group of composite components are dried microalgae Spirulina, which is known to efficiently adsorb various metallic salts from their environment. The last type of component is halloysite, a natural mineral. It is widely studied and reported that inorganic materials such as silica and clay can improve the mechanical properties of the composites that they form with polymers. Because halloysite’s chemical structure consists of silica and alumina, it is expected to be efficient in adsorbing both anionic and cationic dyes due to the presence of negative and positive ions in its structure. Hence a group of composites with various properties are prepared through a convenient method by mixing multiple components in a range of different ratios within solutions. Resulting composites are tested for their stability and swelling properties in water, and adsorption capacities of two types of charged dyes, anionic and cationic. This work is expected to contribute to ‘sustainable development’ efforts.