A novel permanganate and peroxide carbon-based avocado seed waste for the adsorption of manganese and chromium ions from water
Koketso Mabalane, Ntaote David Shooto, Patience Mapule Thabede
Abstract
Activated carbon from avocado seed waste was processed for the sorption of manganese and chromium ions from contaminated water to protect water quality and human health. The aim was to convert pristine avocado seed waste into carbon and then activate it with hydrogen peroxide, potassium permanganate and nitric acid to facilitate the adsorption of manganese and chromium ions from aqueous media. The variation of the parameters such as pH of the solution, reaction time, initial concentration and temperature were investigated. The results show that the adsorbent modified with hydrogen peroxide has a large surface area compared to the other adsorbents. The maximum adsorption capacity for manganese and chromium ions was achieved at a pH value of 2. The results show that the removal efficiency of manganese and chromium ions increases with increasing contact time in the initial phase of the process and the adsorption rate is also fast before reaching equilibrium. The maximum adsorption capacities of manganese and chromium ions were found to be 49.95 and 48.96 mg/g, respectively. The adsorption data also showed that the Freundlich model describes the adsorption isotherm with multilayer coverage well. The highest sorption capacity was observed for the carbon activated with hydrogen peroxide and was expected due to the large surface area. The proposed adsorbent thus represents a cost-effective material that can be considered as a viable alternative for the effective adsorption of manganese and chromium ions from water samples. The experimental conditions and the method used also make the avocado seed waste a suitable material for environmental monitoring.