Development of effective and sustainable adsorbent biomaterial from an agricultural waste material: Cu(II) removal

Motivated by the significant scope which exists to generate value-added products from agricultural waste materials, in this work a comprehensive study was performed on the microstructure of alkali-treated coconut coir in order to evaluate its potential as an environmentally friendly absorbent. By investigating the influence of the alkali concentration, temperature and treatment time through a systematic Design of Experiments (DOE) approach, it was found that alkali-treated coconut coir possessed greatly improved water and moisture absorption properties (27% and 30% increases, respectively, compared to those of untreated coconut coir). The efficiency of heavy metal removal of treated coconut coir samples has been studied by investigating Cu (II) removal performance of selected samples with higher water and moisture absorbency. The effect of contact time and concentration of Cu (II) on the Cu (II) removal efficiency of samples have been investigated. The results show almost five times higher Cu (II) removal performance for the treated sample compared to raw coconut coir under optimized conditions. These findings highlight that the alkali treatment of biomaterials such as coconut coir can be used to tailor their water-absorbency properties as well as their adsorption properties, providing facile and effective adsorbent materials from readily available agricultural waste materials.