**1. Introduction**

Unquestionably; water is the source of life and one of the most important material resources for human existence and advancement. Although 71% of the earth's surface is covered with water; approximately 98% of our water is salty and only 2% is fresh. Of that 2%, almost 70% is snow and ice, 30% is groundwater and less than 0.5% is surface these are freshwater resources that can be directly used by humans, such as river water, freshwater lakes, and shallow groundwater [1]. Meaning; there is no surplus fresh water in the planet. In addition to this, modernization that demands the fast development of industries and increasing human activities, forced many harmful inorganic and organic pollutants to be released into water, which extremely jeopardizes the available freshwater resource and ecological environment. Today according to the world population clock, the population exceeds 7 billion and will reach 10 billion by 2050. These all indicates pure drinking water would be a major problem all over the world, especially for the developing countries [1].

As a kind of technology which can increase the amount of freshwater, desalination of the salty water and treating the polluted water have become a strategic choice to solve the crisis of water resources. Currently, the global volume of desalinated water

has exceeded 90 million m3 /day, alleviating water shortages which have affected over 200 million people [1, 2]. Reusable water obtained from treating the wastewater is not as such considerable [3, 4].

To desalinate water a number of process technologies are used. The mentioned techniques are (1) reverse osmosis (RO), distillation, freezing, hydration and solvent extraction, etc. or (2) ion exchange, electro-dialysis (ED), adsorption capacitance, pressure impregnation and forward osmosis (FO) technology [1–3]. Out of the mentioned technologies; three of the processes require the use of semipermeable membranes.

Literature indicated membrane technology has become a dignified separation technology over the past few decades [2] and from **Figure 1** the polymer based membrane technology is in the forefront of water purification and desalination, owing to its advantages of low energy consumption (as compared to other technology, low investment cost, ease of operation and possibility for continuous operation and inherent simplicity) [3, 5], but is plagued with some bottlenecks like most of them tend to foul, have low resistance to chlorine, strong acids/alkaline, high temperature and organic solvents, and suffer from aperture shrinkage under high pressure [1, 3]. And despite large scale seawater desalination plants have already confirmed their much needed success, the widespread implementation of these plants is held back due to their high energy costs. One approach to resolve the mentioned problems is through enhancing a membrane used in separation process. A tremendous amount of effort has been paid to develop new membranes and develop novel membrane structures with greater chemical stability, thermal stability, water permeability, as well as high selectivity, which in turn yield less energy consumption [6–10].

Since 2004; researcher focused on carbon-based materials especially one materialgraphene. Graphene and its derivative graphene oxide (GO) and carbon nanotubes

#### **Figure 1.**

*Trends in global desalination by (a) number and capacity of total and operational desalination facilities and (b) operational capacity by desalination technology (https://www.desaldata.com/).*

*Graphene Oxide-Based Membranes as Water Separation: Materials, Preparation… DOI: http://dx.doi.org/10.5772/intechopen.105371*

(CNTs) have demonstrated notable potential in the field of membrane. The basic characters for their suitability are their strong mechanical strength, high resistance to strong acids/alkaline and organic solvents, and easy availability. Among them, GO selected for evolving nano-building materials for the manufacturing of novel separation membrane due to its high mechanical strength, high chemical inertness, nearly frictionless surface, its flexibility, suitability for large-scale production and its cost-effectiveness [5–10].

In this mini review first an introduction about membrane, graphene and graphene oxide (GO) are provided. Then it is tried shortly to discusses points on the preparation and characterization of GO. Finally the preparation method, characterization, and type of GO-based membrane are discussed.
