Pollution is one of the major problems in most of the developing and developed countries. Water pollution remains a source of constant concern for environmentalists. With the growth of industrialization and globalization this issue is rising day by day. Several types of methods and materials have been used to avoid these problems, but often the methods proved to be useless in the absence of proper method and materials. In order to streamline these methods such as ion exchange, membrane filtration and adsorption, continuous new types of effort and materials are being made. In the material used so far, the best features of composite materials have come out, which has opened a new door in the field of treatment technologies. Composite is made up of different types of material having unique properties. The combination of different desired material is required to obtain the desired results in the composites thus resultant composites prove to be highly advance, unique and beneficial. In this chapter, we have discussed the different types of composite materials, and their preparation strategies and applications. The detail study on matrix and reinforced material based composites, and green composites have been conducted. This chapter will definitely be the preferred choice of environmentalists.
1.1 Introduction
Concerned with the problems of the environment, environmental engineers are developing the solutions by using the principles of biology and chemistry. Most common issues on which the engineers are focussed currently are disposal and recycling of the waste materials, air and water pollution, controlling the public health issues, removal of polluting substances from the surroundings, harmful effects caused by acid rain, global warming, auto mobile emissions, depletion of ozone layer etc. [1–3]. These effect the ecosystem which ultimately leads to human health problems and may sometimes even prove fatal. One such matter rising at the global level is water pollution [4–7]. Water which is a very precious resource is useful for us in a number of ways but its quality is degrading day by day. Major sources of water pollution include industrial, municipal, agricultural, natural, storm water, landfill, underground storage tank etc. [8–11]. Among them industrial waste plays a major role in polluting water bodies that release dyes and harmful metal ions [12, 13]. Human health is affected to a great extent and sometimes even proves fatal [14–16].
In the present times many types of materials or combination of material are being used for reducing the environmental pollution. Composites are one such type.
Composites can be defined as “artificially made material made by the combination of two or more material that is different in the properties of its constituent”. Both the constituents are chemically different from each other and are separated by an interface [16–19]. Composites are different from that of conventional materials because of their superior properties [17–20]. Composites contain a continuous phase called Matrix and dispersed or discontinuous phase called Reinforcement or reinforcing material. Properties of the particles get changed when the size of the particles is below their critical size. As dimensions reach the nanometre level, the interactions at phase interfaces become largely improved, and this plays an important part in enhancing materials properties [21]. Matrix can be made from polymer (synthetic or natural), metal, ceramics and resins while the reinforcement are the nanoparticles, fibers, filled, whiskers, flakes, particulates, directionally solidified eutectics. Engineers and scientist are trying to make composites having better and better properties by combining different metals, alloys, ceramics, and reinforcement material. As a result of which composites are used for a wide range of applications.
With the current advancements, composites are being replaced by the nanocomposites. A nanocomposite can be defined as a composite material formed by the combination of two or more components in which one component phase have nanoscale dimensions (0D,1D,2D) that is around 10–9 m. This nanometre sized materials are dispersed/embedded in the matrix of a polymer, metal or ceramic. It is a multiphase solid material. Nanocomposites are very much different from conventional composites for the exceptionally high surface to volume ratio of the reinforcing material and/or its exceptionally high accept ratio.
Following parameters affect their properties like process used in the synthesis, material of the matrix which can exhibit nanoscale dimensions, loading, modification of the surface of nanoparticles, dispersion degree, size, shape and orientation of the nanoscale reinforcement phase and interaction between the matrix and the reinforcements. Due to the distinct properties of the constituents and inhomogeneous distribution of the reinforcement material these nanocomposites have direction dependent properties which we called anisotropy [22]. Interphase plays a very important role in the properties of the composites which tells us about the bonding between matrix and reinforcement material. Elasticity, strength, chemical potential varies from composites to composites since the preparation involves different types of reinforcement and matrices. But as the discontinuity in the above parameters occurs between the reinforcement and matrix, then not only by the medium of transition but also the matrix will create a chemical compound at interface due to the discontinuity in chemical potential [23]. Interfacial bonding is there between interface and matrix. This bonding will be strong and weak depending on the type of composites containing phases. Like in PMCs and MMCs strong...
