Removal of methylene blue from simulated wastewater by Carica papaya wood biosorbent

Dye application occurs in several industries such as the textile, paper and pulp, paint, printing, rubber, and cosmetics industries. During the dyeing process, 1-15% of the dye is lost in the effluent discharge that generates endless quantities of dye-containing wastewater [1]. Synthetic dyes, characterized by complex aromatic structures, are stable enough to withstand heat and light and are considered nonbiodegradable [2, 3]. Discharge of these dyes into effluent may impart toxicity to aquatic life and may be carcinogenic or mutagenic to human beings, which causes serious damage such as dysfunction of the kidneys, reproductive system, liver, brain, and central nervous system [4-6]. Methylene blue (MB) is a cationic dye that is widely used in dyeing cotton, wool, coloured paper, and coatings for paper stocks [7]. Table 1 represents the general characteristics of methylene blue.