The use of biochar‑NH2 produced from watermelon peels as a natural adsorbent for the removal of Cu(II) ion from water

Abstract

While various techniques have been explored for the sequestration of heavy metals such as copper from industrial efflu ent, there is enormous research on the use of biosorbents created from bio-waste in the environment for the confiscation of Cu(II) ion owing to their low cost and green nature. In this study, a biochar-NH2 biosorbent synthesized from watermelon peels was explored for the elimination of Cu(II) ion from water-soluble solutions. The synthesized biochar-NH2 was further characterized using FTIR, BET, and SEM coupled with EDX to ascertain the present functional groups, the surface area, morphology, and elementary composition of the biosorbent. The determined biochar-NH2 BET-specific surface area and the total pore volume were 12.26 m2 /g and 0.012 cm3 /g. The differential thermal analysis (DTA) of the WWP and biochar NH2 samples showed six peaks at flow temperatures of 769, 178, 251, 292, 426, and 872 °C, and two distinct degradation peaks at flow temperatures of 767 and 477 °C. The sequestration of Cu(II) was noted in this study to be dependent on the pH, with the best possible confiscation of Cu(II) ion noticed at pH 5.6. The process of Cu(II) adsorption to the biosorbent was perfectly defined utilizing the Langmuir (LGR) and pseudo-second-order (PSO) models with correlation coefficient (R2 ) values of 0.944 and<0.99. It is implicit that the sorption process consists of a chemisorption process in rate-limiting stages. The determined sorption capacity estimated from the Langmuir isotherm model was determined to be 140.85 mg/g and when the sorption capacity of biochar-NH2 was compared to other biosorbents employed for the sequestration of Cu(II) ion from water-soluble solutions, the biochar-NH2 biosorbent was found to be an effective biosorbent for Cu(II) elimination. Additionally, it was found that the biosorbent can be regenerated up to six regeneration cycles for the confiscation of Cu(II) ion. In conclusion, it was discovered in this study that the synthesized biosorbent was a cost-effective adsorbent with a high adsorption efficacy for Cu(II) removal.