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Introduction

Chitin is among the most universal natural occurring polysaccharides, second only to cellulose (El Knidri et al., 2018). It is a biopolymer produced by a large number of terrestrial and aquatic flora and fauna. Its crystalline nature is depicted in the exoskeletal systems of various known insects (Kamal et al., 2020).

Commercially, aquatic life has been the main source of chitin; commonly in the forms of crabs, clams and shrimps (Bernardi et al., 2018). Chitin possesses a structural identity close to that of cellulose, but with a different positioning of the acetamide groups. The main polymer derivative of Chitin is Chitosan, which is a linear polymer (Crini, 2019).

The trend of cellulose being depicted as the landmine of biopolymer resources has been seen to fade, as Chitin is currently championed globally as the “biopolymer of the future”; with an annual global production rate competing with that of cellulose (Rao et al., 2014). It has received the nod globally as the novel biomaterial with near limitless functionality and potentials in various realms of science and technology. This depicts the enormous global significance of Chitin (Islam et al., 2017).

Chitin is an excellent biopolymer due to its superb qualities with respect to its renewability, bio-degradability, adsorption properties, sustainability, reasonable inertness, non-toxicity, and bio-compatibility (Shamshina et al., 2019).  It has been demonstrated that Chitin possesses a higher versatility than cellulose due to its polymeric chain arrangements, and the presence of its intrinsic amine groups (Khattak et al., 2019).

Industrially, Chitin undergoes dissolution in the presence of both acid and alkaline solutions respectively in order to dissolve its carbonate and protein groups (Song et al., 2018). Furthermore for aesthetics, a decolourization step is usually undergone (Shamshina, 2019).  A major issue in the industrial processing of Chitin is its insolubility as it is seriously hydrophobic and also insoluble in organic solvents (Doan et al., 2019).

Chitin is similar to Cellulose in that complex living organisms find it difficult to digest, ironically it is easily biodegradable which makes it a great material for numerous industrial applications (Yates and Barlow, 2013).

Most aquatic  scales contain about chitin within the range of 20-30%, with the remaining composition being protein groups and calcium carbonate (Kaya et al., 2017). The scales also contain lipidic pigments (Moussian, 2019). Chitin undergoes acid treatment to enable dissolution of the Calcium Carbonate, and also alkaline extraction in order to dissolve the protein groups (Antunes-Valcareggi et al., 2017). A depigmentation process is also not neglected in order to attain a product without colour (Lopes et al., 2018).

The extraction of the proteins from Chitin is usually done heterogeneously; this breaks down the chitin biopolymer into lighter chains. This process is usually a difficult one; as it disintegrates the bonds between Chitin and the shells’ intrinsic protein groups (Gadgey and Bahekar, 2017). However, this process is very significant because a total removal of the protein groups is essentially important; the protein-less Chitin finds numerous applications in biomedicine (Hamdi et al., 2017).

Various alkali reagents have been used to carry out the de-proteinization (Mechri et al., 2019). Sodium hydroxide stands out among the alkali reagents, as it can be used at very suitable process conditions; the reaction temperature, reaction time and reagent concentration (Soon et al., 2018).

The acid treatment of the crustacean shells takes place as a form of demineralization (Zhou et al., 2019). Sulphuric acid, nitric acid and hydrochloric acid are among the preferred reagents for acid treatment (Oyekunle and Omoleye, 2019). Dilute hydrochloric acid is mostly used as it has the shortest demineralization reaction time, as seen from literature (Alabaraoye, 2018).

The reagent concentrations are the most important process variables in both the deproteinization and demineralization reaction for obtaining Chitin from aquatic scales, among other process variables (Rasti et al., 2017). Different literature reviews have shown that a reagent concentration above the optimum reagent concentration would bleach the Chitin to be gotten from the feed aquatic scales and also damage the Chitin entirely; thereby not achieving the process aim and also wasting process reagents (Tokatl? and Demirdöven, 2018). A reagent concentration below the optimum point would also not give the optimum yield of Chitin from the aquatic scales. Therefore this is a very important issue in achieving the maximum yield of Chitin from the aquatic scales, this process variable would have to be fine-tuned (Al shaqsi et al., 2020).

Problem Statement

Chitin has been shown to have significant use in the novel areas of science and technology, notably in the area of biomedicine. Hence, its significant production is an essential global need. This need is why the optimal conditions for the production of Chitin industrially have to be taken quite seriously (Duan et al., 2018).

Reagent concentration for the extraction of chitin from fish scales, above the optimum value has been depicted to damage and bleach the required final product (Chitin), while reagent concentration below  the optimum value do not give an optimal production of Chitin (Hassainia et al., 2018).

Therefore, the concentration of hydrochloric acid and sodium hydroxide that would give a maximum yield of Chitin from aquatic scales have to be figured out.

Aim and objectives

The aim of this study is to determine the optimum concentrations of both hydrochloric acid and sodium hydroxide that would give a maximum yield of Chitin from fish scales, with the following objectives;

• Objective 1: To develop an optimum condition for production of Chitin from fish scales.
• Objective 2: To vary the concentration of HCl and record the yields at different concentrations of HCl.
• Objective 3: To vary the concentration of NaOH and record the yields at different concentrations of NaOH.
• Objective 4: To test the chemically properties of the Chitin extracted from the fish scales.
• Objective 5: To carry out FTIR, SEM, XRD and ash test on the chitin extracted from fish scales

Research Questions

The identified research questions for this project are provided below:

• What is the optimum condition for the production of Chitin from fish scales?
• What concentration of HCl would give a maximum yield of Chitin from fish scales?
• What concentration of NaOH would give a maximum yield of Chitin from fish scales?

Deliverables

The deliverables of these projects are a project report and attained results.  Also, the report should contain a complete documentation of how the laboratory experiment was carried out, how various reagent concentrations affected the Chitin yield, how various process variables were gotten, and how the results were arrived at.

Relevance

This study is majorly focused on obtaining the best concentration of HCl/NaOH needed to get maximum yield of chitin from fish scales at an optimum condition.

Methodology

This project focuses on secondary research, laboratory experiments and process analysis, and they are discussed below:

Secondary research

The secondary research in this project will utilize a systematic approach (Johnson et al., 2016) to review the works of literature. The steps involved in the systematic review of the literature are provided below:

• Step 1: Identify the research questions that can be used for the project.
• Step 2: Identify the keywords that should be used to research the works of literature.
• Step 3: Extract the journals and books that are appropriate for this project.
• Step 4: Write the literature review chapter.

Laboratory experiments

The laboratory experiments would cover a large chunk of this project. They would be carried out in stages, and as such described below;

• Stage 1:  Sourcing for the required feedstock (fish scales) and other required raw materials.
• Stage 2:  Developing an appropriate process route and optimal equipment arrangement for an efficient process setup (Zhang and Rolandi, 2017).
• Stage 3:  Carrying out the process reaction.
• Stage 4:  Analyzing the process reaction.
• Stage 5:  Varying the reagent concentrations and obtaining various yields
• Stage 6:  Characterization of the resultant Chitin (Hassainia et al., 2018).
• Stage 7:  Results Testing.

Process Analysis

The totality of the process reaction would be analyzed and this would also occur in stages;

• Stage 1:  Process Testing
• Stage 2:  Process Control
• Stage 3:  Process Optimization

Evaluation

The risk assessment conducted for this project is provided in the table below:

Table 1:  Risk assessment