Biomass Adsorbent for Removal of Toxic Metal Ions From Electroplating Industry Wastewater

Abstract

Materials of natural origin are generally used in biosorption studies (such as seaweed, biological depuration plant sludge, agricultural and industrial wastes) are inexhaustible, low-cost and non-hazardous materials, which are specifically selective for different contaminants and easily disposed by incineration.The biosorbent terms refers to material derived from microbial biomass, seaweed or plants that exhibit adsorptive properties.Biosorption is the accumulation of metals by biological www.intechopen.comElectroplating 102 materials without active uptake.This process may include ion exchange, coordination, complexation, chelation, adsorption and microprecipitation (Duncan et al., 1994) This biomass must be subjected to pre-treatment to obtain a better operating performance in pollutant removal using adsorption method (Naja et al., 2010).An interesting feature is that the biosorbents are widely found in nature and they have low cost.In some cases they are agriculture waste such as corn cob (Shen & Duvnjak, 2005), coconut shell (Sousa, 2007) , orange pulp (Almeida, 2005), peat (Gupta et al 2009) andsawdust (Yasemin &Zaki, 2007) Ions metal biosorptionThe process is based on the interaction of ions at the interface biomass / aqueous medium.The sorbent can be either a particulate material as a compact material.The separation can be performed in packed columns, fluidized beds or in the form of discs to be used in the filtration process.This configuration allows for regeneration and reuse of the adsorbent and its proper disposal (Vargas et al, 1995).The discovery and development of the biosorption process has supported the basis for an new technology in this field.Several authors have been devoted to the study and applicability of this new kind of technology (White, 1995;Volesky, 1990).Agricultural waste is one of the rich sources of low-cost adsorbents besides industrial byproduct and natural material.Due to its abundant availability agricultural waste such as peanut husk, rice husk, coconut shell, wheat bran and sawdust offer little economic value and, moreover, create serious disposal problems (Igwe & Abia,2007).Biosorption is the capability of active sites on the surface of biomaterials to bind and concentrate heavy metals from even the most dilute aqueous solutions.Biosorption can be used for the treatment of wastewater with low heavy metal concentration as an inexpensive, simple and effective alternative to conventional methods.The process of metal ion binding is comprised of many physico-chemical processes like ion exchange, complexation, microprecipitation, and electrostatic interactions.Biosorbents for the removal of metals mainly come under the following categories: bacteria, fungi, algae, industrial wastes, agricultural wastes and other polysaccharide materials.In general, all types of biomaterials have shown good biosorption capacities towards all types of metal ions (Febrianto et al., 2009) The biosorption results from electrostatic interactions and/or of the formation of complexes between metal ions and functional groups present on the surface of biosorbent.So many studies have been conducted to assess the potential for removing heavy metals from various biological materials (Hayashi , 2001).We can cite the seaweeds and their derivatives (Luo et al, 2006), chitosan (Ngah et al, 2011), lignin (Guo et al, 2008), wide variety of bacteria and fungi (Watanabe et al, 2003), agricultural residues (Sousa, 2007), among others.According to Volesky, (1990) biosorbent must have certain physical characteristics (surface area, porosity, grain size etc.) to get good ability to adsorption and to be used in an adsorption process. Adsorbent used for removing pollutantsAdsorption process is essentially a surface phenomenon.Adsorbent having a good adsorptive capacity implies that it should present a large specific surface area.The adsorptive properties depend on the distribution of size pore and the nature of the solid surface.The adsorbents www.intechopen.com