Use of agro-waste ( Musa paradisiaca peels ) as a sustainable biosorbent for toxic metal ions removal from contaminated water

ISSN: 2410-9649 Ibisi and Asoluka / Chemistry International 4(1) (2018) 52-59 iscientic.org. 106 www.bosaljournals/chemint/ editorci@bosaljournals.com Most heavy metal ions are reported as priority pollutants, due to their mobility in natural water ecosystem and due to their toxicity (Demirbas, 2008). The problem associated with metal ions pollution is that they are not biodegradable and are highly persistent in the environment. Thus they can be accumulated in living tissues causing various diseases and disorders (Wan-Ngah and Hanafiah, 2008). Heavy metal toxicity can result in damage or reduced mental and control nervous functions, lower energy levels and damage blood composition, lungs, liver, kidney and other vital organs (Ahmaruzzam, 2011). It is thus necessary to remove heavy metal ions from contaminated or waste water before it can be discharged into the environment. In this respect, many physico-chemical methods have been developed for the removal of heavy metal ions from aqueous solution including; precipitation, evaporation, electrodeposition, ion exchange, membrane separation, coagulation etc (Rao and Ikram, 2011). However, these methods have disadvantages such as secondary pollution, high cost, high energy input, and large quantities of chemical reagents or poor treatment efficiency at low metal concentration (Ding et al., 2012). It can be said that the conventional methods for metal ions removal from contaminated water are limited by technical and economic barriers especially when concentration of heavy metal ions in the water is low (< 100ppm) (Witek-Krowiak et al., 2011). Therefore the search and development of efficient and lowcost metal removal processes are of utmost importance. The growing trend in biotechnology has resulted to the emergence of bio-adsorption as an alternative and sustainable strategy for treating contaminated water. (Flores-Gamica et al., 2013). Biosorption uses inexpensive biomaterials to sequester environmental pollutants from aqueous solutions by a wide range of physico-chemical mechanism, including ion exchange, chelation, complexation, physical adsorption, and surface micro precipitation. The biomaterials used in these processes are termed bioadsorbent (Flores-Gamica et al., 2013). Biosorption is a physical chemical process, simply defined as the removal of substance from solution by biological material. This is a property of both living and dead organisms (and their components) and has been heralded as a promising biotechnology because of its simplicity, analogous operation to conventional ion-exchange technology, apparent efficiency and availability of biomass and waste bio-products (Kelly-Vargas et al., 2012). Various waste biomaterials, microorganisms, bacteria, fungi, yeast and algae have been reported for the removal of heavy metal ions from aqueous solution (contaminated water) (Ghaedi et al., 2013). In this regard, besides treatment of contaminated waste water biosorption application proffers a sustainable means of waste management. One of the key sources of bioadsorbents is Agro waste materials. Agricultural waste represents a potential source for producing biosorbents as they have no prominent utilization. The use of agro waste to treat contaminated water may add value to agro-waste and eventually reduce the agro waste management problems around the world (Hossain et al., 2012). Agro-materials are composed of lignin and cellulose as major constituents and may also include other polar functional groups of lignin which include alcohol, aldehydes, phenolic and ether groups (Hossain et al., 2012). These groups are behind the chemistry of biosorption or removal of heavy metal ions from contaminated water. During the past few years, several research articles were published reporting the successful use of different kinds of agricultural waste in the removal of toxic metal ions from contaminated water. These led to the interest in this study on the use of Musa paradisca (plantain) peels in the removal of heavy metal ions from heavy metal contaminated water. Botanical description of the test biosorbent (Musa paradisiaca) Plantain plant is a crop plant with green leaves and herbaceous stem. The fruit which is green is typically larger than the common banana and is cherished by many people in Abia state, Nigeria (Mohammed and selena, 2012). Plantain (Musa paradisiaca) belongs to the Eumusa of the genus Musa, family (Musaceae) closely related to the common banana (Musa sapientum) (Andrede et al., 2008). The plantain is a tall plant with a conical false '' trunk'' formed by the leaf sheaths of its spiraling arranged leaves, which are 1.5 3m long and about 0.5m wide. Rodrigues et al., (2005), highlighted that, plantain species are classified either by bunch floral size or size of the pseudostem (false stem). He classified bunch type and floral size based on their characteristics into; French plantain, French horn plantain, horn plantain, false horn plantain and further classified the size of the pseudostem into; giant plantain, medium plantain, and small plantain. A plantain peel is the outer covering of the plantain fruit. Plantains, whether eaten raw or cooked, are popular fruits consumed worldwide, and its Global production has risen by nearly 60% over the last 30 years to 37 million metric tons. Uganda is by far the largest producer with 9.6 million metric tons compared with the second largest producer, Ghana, with 3.6 million metric tons. Other important producers are Rwanda, Nigeria, Cameroon, and Colombia. Plantain production in Africa has nearly doubled over the last 30 years to 27 million metric tons. There is a significant amount of plantain peel waste being generated as well. To convert the waste generated from plantain production (in form of plantain peels) into more value added product we suggest that, it can be used as biosorbent in removing toxic metals from heavy metals contaminated water which will yield sustainable and eco-friendly way of treating toxic metal contaminated effluent and waste management. This study investigates the use of Musa paradisiaca peels as sustainable biosorbent in toxic metal removal from metal ions solution. MATERIAL AND METHODS Sample collection and identification ISSN: 2410-9649 Ibisi and Asoluka / Chemistry International 4(1) (2018) 52-59 iscientic.org. 107 www.bosaljournals/chemint/ editorci@bosaljournals.com The test sample Musa paradisiaca peels were collected and sorted from west beans around Michael Okpara University of Agriculture Umudike (MOUAU) environs. The collected sample was identified in Forestry Department College of Natural resources and environmental management Michael Okpara University of Agriculture Umudike Abia state Nigeria. Adsorbent sample preparation The Agro-waste was brought to chemistry laboratory, Chemistry Department, College Of Physical And Applied Sciences, MOUAU. In the laboratory the sample was spread on laboratory work bench and inspected for extraneous material such as insect larva. Thereafter the sample was washed and cut into pieces to increase the surface area for easy drying. Then the sample was oven dried at 60°C until it became dried and then dry milled to powdery form, followed by sieving through a 0.63 to 1.6mm. The resultant fine sample was collected and soaked in dilute nitric acid (2%) solution, filtered and washed repeatedly in distilled water and oven dried at 60 °C. Thereafter, the sample was rewashed in 1% NaHCO3 to remove any remaining acid, and then washed with distilled water until pH of 6.0 was obtained. Subsequently the washed sample was dried at 60°C for 5 hours and stored for adsorption analysis. Adsorbate solution preparation Known qualities of cadmium chloride and lead acetate were separately dissolved in distilled de-ionized water in one liter volumetric flask and made up to mark with distilled deionized water to form stock solution. From the resultant metal ion stock solutions test solutions of 50mg\l, 100mg/l, 150mg/l and 200mg/l were obtained using dilution formula in equation 1.