India's population now exceeds 1400 million. Humans have three basic needs: food, clothing and shelter. For the expansion of textile industry, it requires a lot of water for all steps ofmanufacturing. For example, one kilogram of fabric is produced in a small textile factory using 250 gallons of water [1, 2]. The wastewater produced by the company does not have the vital quality to meet reusable water standards. Industrial wastewater has a high content of total waste, hardness and other chemical substances [3]. This makes the water unsuitable for reusing it. Due to the growth of the textile industry, a large amount of wastewater, including waste produced duringproduction, causes many diseases, effects aquatic life, underground and open water pollution [3]. These are basic reasons for wastewater treatment. However, the affordability of wastewater treatment processes is expensive and complex. This phenomenon can be solved by using natural and eco-friendly adsorbents.
Owing to various parametercharacteristics, textile wastewater is one of the waters most common waste [4]. If disposed of illegally, this wastewater can do serious impairment to the environment and endanger to humanoid[5]. More than 10,000 colours or dyes are used in textile production [6]. When discharged into water bodies, the colourfulcolour is related to the oxygenation and solar absorption capacity of water, causing serious harm to the biological process of aquatic organisms. As the number and types of textile products increase, the industry uses a variety of dyes containing different chemicals, making the wastewater treatment process more complex. In aquatic organisms, dyes have mutagenic, teratogenic and carcinogenic effects [7]. It is therefore important to limit or fully treat the dye pollution before discharging it into the water bodies.
Of all the dyes, methylene blue is the most commonly used dye in textile, makeup and paint industry. It is one of the synthetic pigments that disperses in water to create a dark blue shade. Methylene blue is much problematic due toitsconsequenceofaccumulation inside cytoplasmand cell[7]. High visibility water that contains small amounts of methylene blue affects aquatic life by interfering with the transmission of oxygen and light. Methylene blue wastewater must therefore be disposed of correctly.
The methylene blue dye removal from wastewater was testified by employing various techniques like liquid-liquid extraction, reverse osmosis, advanced oxidation process, electrocoagulation, electrochemical oxidation, ozonation, and membrane filtration [8]. Contrary to all those techniques, adsorption process established more advantages as a result of its modest design, higher dye removal efficiency and various carbon materials as adsorbent along with unhazardous by-products [9]. Since activated carbon is expensive, it is infrequently used as an adsorbent in advanced countries. Accordingly, many researchers have shifted focus on developing inexpensive adsorbents. Researchers have moved interest towards the agricultural wastes based activated carbon, whichmake available as adsorbent as well as resolve waste disposal issuesoverall [10].Various farming wastes for instance jackfruit leaf, peanut casing, watermelonskin and banana stem are considered as viable andlow-priced adsorbent resources [11–13].
Among those, banana stem is having high capacity as adsorbent and one of the agriculturalwasteswhich exist worldwide. Through worldwidecultivation, banana stem countsmajor 60% as compared toitsleaf and fruitpercentage [4]. Banana stem hascontentsof cellulose, hemicellulose and lignin as 43.3%, 20.6% and 27.8% individuallywhich makes banana stem asalternativepotential source of activated carbon.Okky et al., used adsorbent of banana peel activated carbon for methylene blue dyes fromfabricwastewaterand determineddyeelimination of 4–20% [12].Erniet al., used banana stem activated carbon and detected very good dye removal efficiency [10].
In this work,banana stem activated carbon was investigatedas methylene blue dyeadsorbent and removal efficiency wasanalysed. For activation of banana stem carbon, phosphoric acid (H3PO4) solution was used. The adsorption was examined by changing various parameters(such as pH of dye solution from 3–9, doses of activated carbon, dye concentration etc.)and removal efficiencies of methylene bluedyeswere determined accordingly.