Essay Example on To synthesize chitin chitosan from crab and shrimp Shells









Objectives To synthesize chitin chitosan from crab and shrimp shells To characterize chitin chitosan for wastewater treatment applications and To test chitin chitosan for the adsorption of Pb2 and Cu2 on contaminated water Synthesis of chitosan for lead and copper adsorption in waste waters Ryan Gabatino Sally Gano Katrina Guzman Dindi Guzon and Emer Niones Department of Mining Metallurgical and Materials Engineering College of Engineering University of the Philippines Diliman Quezon City ABSTRACT Heavy metal ions such as Pb II and Cu II are commonly found in industrial and mining wastewaters At high concentrations these ions become toxic to humans and animals and may even be detrimental to their health One technique to eliminate Pb II and Cu II from industrial wastewaters involves the use of chitosan as an adsorbent Chitosan is a derivative from the second most common naturally occurring polymer chitin and is primarily sourced from crustaceans such as shrimps and crabs Having synthesized chitosan and characterizing it in this experiment it was found to have an adsorption capacity of 127 mg g Its high performance thus indicates promising potentials as an eco friendly and economic adsorbent for Pb II and Cu II 

INTRODUCTION Chitosan is a biomaterial characterized by the primary amines present on its backbone It is produced through the deacetylation of chitin a naturally occurring polysaccharide found in the exoskeleton of crustaceans This process increases the number of functional groups present in the original structure of chitin making it an effective adsorbent Equipped with hydroxyl and amines chitosan is able to trap heavy metal ions such as Pb II and Cu II onto its structure effectively through either chemical or physical adsorption Chitosan is also biodegradable and non toxic making it much more harmless to the environment compared to present day synthetic chelating agents Ravi Kumar 2000 With a good number of industries polluting the environment today wastewater treatment has become increasingly important despite the expenses it curtails Therefore this study aims to propose a more economic solution to the high costs of conventional technology by introducing chitosan as an alternative to costly yet inefficient filtration systems developed today Hadi 2013 

METHODOLOGY 1 Chitosan Synthesis The general procedure of chitin extraction from crustaceans as stated by Shimahara and Takiguchi was followed To maximize the amount and quality of extracted chitin optimum conditions for extraction was followed from the findings of Chang et al Prior to chitin extraction crab and shrimp shells were scraped clean and rinsed with water air dried and crushed into about 0 50 cm2 chips The shells were demineralized by immersing them in 1 70 N HCl for 6 hours at 9 00 mL g solution to solid ratio The demineralized shells were deionized and air dried before the following deproteinization step which consists of immersing the dried shells for 6 hours into 2 50 N NaOH at 75 C at about 5 mL g solution to solid ratio Rinsing and air drying produces the crude chitin by product which is finally subject to heterogenous deacetylation to form water insoluble chitosan which is done by mixing the crude chitin with 50 aqueous NaOH and stirred for 3 12 hours at 100 C Sivashankari 2017 2 Chitosan Characterization The extracted chitosan was subjected to infrared IR spectroscopy for characterization About 40 60 mg of chitosan powder was blended with 120 mg of potassium bromide KBr The resulting mixture was then triturated with a mortar and pestle for 10 minutes Next about 40 mg of the triturated mixture was compacted at a pressure of eight tons for one minute using the IR hydraulic press Then the disk was placed in a desiccator placed inside an oven at 80 C for 16 hours Lastly the spectra of the samples were obtained at a frequency range of 4000 404 cm 1 3 Pb2 and Cu2 Adsorption Standard solutions of cupric chloride CuCl2 hydrocloric acid HCl sodium hydroxide NaOH 1 chloro 2 3 epoxy propan epichchlorohydrin lead II chloride PbCl2 Yang and Zall 1984 and chitosan were all prepared using 18 2 M Ω cm Millipore milli Q deionised water

The experiment was done in batches at room temperature 25 C using cupric chloride and lead II chloride to produce solutions of Pb2 and Cu2 with a concentration ranging from 10 to 1000 mg L In 300 mL of the metal solution 1 g of chitosan was mixed The removal of chitosan from the mixture during sampling was prevented by using a syringe as a filter The solutions were analysed using an atomic absorption AA spectrometer while the concentration of Pb2 and Cu2 in the mixtures was determined by using a Varian Spectre AA 250 a computer and a printer Schmuhl Krieg and Keizer 2018 References Chang KLB Tsai G Response surface optimization and kinetics of of isolating chitin from pick shrimp Solenocera melantho shell waste in Journal Agricult Food Chem 1997 45 1900 1904 Hadi A G 2013 Synthesis of Chitosan and Its Use in Metal Removal Chemistry and Materials Research 3 3 Retrieved January 21 2018 from https pdfs semanticscholar org a022 76cf9f5c674e78bd4e54304bdec059576ddf pdf Ravi Kumar M 2000 A review of chitin and chitosan applications Reactive and Functional Polymers 46 1 pp 1 27 Schmuhl R Krieg H and Keizer K 2018 Adsorption of Cu II and Cr VI ions by chitosan kinetics and equilibrium studies Shimahara K Takiguchi Y Preparation of crustacean chitin in Methods in Enzymology 1988 161 Sivashankari P R Prabaharan M Deacetylation modification techniques of chitin and chitosan in Chitosan Based Biomaterials Vol I 2017 117 133 Yang T and Zall R 1984 Absorption of metals by natural polymers generated from seafood processing wastes Industrial Engineering Chemistry Product Research and Development 23 1 pp 168 172

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