Development of Biosorbent Derived from the Endocarp Waste of Gayo Coffee for Lead Removal in Liquid Wastewater—Effects of Chemical Activators

Abstract

This study reports the development of bio-based adsorbent by utilizing coffee endocarp (CE) waste as a raw material for lead (Pb) removal from liquid wastewater. The effect of NaOH and HCl as activation precursors on the characteristics and performance of the resulting adsorbents was investigated. The prepared adsorbents were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray fluorescence (XRF) and Surface Area Analyzer (SAA). The characterization results confirm the positive role of the activation by either NaOH or HCl in enhancing the surface properties of the resulting adsorbents. The chemical activations removed most of impurities leading to smoother surface, pore size enlargement and enhanced surface area to pore volume ratio, which result in an enhanced adsorption capacity and Pb removal efficiency. The raw adsorbent shows 57.7% of Pb removal efficiency and sorption capacity of 174.4 mg/g. On the other hand, after the chemical treatment using HCl and NaOH, the Pb removal efficiencies increased up to 63.9% and 89.86%, with adsorption capacity of 193 and 271.58 mg/g, respectively. Though both activated sorbents demonstrate better adsorption performance compared to the non-activated CE, overall results reveal that the NaOH-activated sorbent offers better characteristic and performance than the HCl-activated sorbent.

Modified Polymeric Biosorbents from Rumex acetosella for the Removal of Heavy Metals in Wastewater

“…The average values of the measurements and the aspect ratio between length and diameter can be seen in Table 6 , in which it can be seen that the chemical treatments carried out allowed the measurements of the biosorbents to be reduced [ 86 ], obtaining a larger surface area contact by the elimination of compounds such as hemicellulose and lignin [ 54 , 90 ]. In the case of the mixed T4 treatment, a greater loss of the original measurements was observed, due to the sequential combination of sulfuric acid and sodium hydroxide [ 91 , 92 , 93 ]. The surface of the biosorbent before the chemical modification was rough and irregular; after the treatment, a greater cracking was observed on the surface, which allowed it to be more porous, thus allowing a more available surface to capture the metal ions As, Cd, Pb and Zn [ 81 , 94 , 95 ].…”

Removal of lead ions (Pb2+) from water and wastewater: a review on the low-cost adsorbents

“…The acid or alkaline treatment of agricultural waste-derived activated carbon typically increased the adsorption capacity (Aziz et al 2019 ). The maximum adsorption capacity of coffee endocarp waste, coffee endocarp waste treated with HCl, coffee endocarp waste treated with NaOH were 174.4, 193.0, and 272.6 mg/g, respectively (Mariana et al 2021 ). The chemical activation increased the adsorption capacity and the removal efficiency.…”

“…The chemical activation increased the adsorption capacity and the removal efficiency. The chemical activation released the impurities on the adsorbent resulting in the widening of the pores and promoting the formation of functional groups that effectively absorb the metal ions (Mariana et al 2021 ). In addition, the NaOH-activated sorbent had the largest surface area to pore volume ratio and the largest pore size, which might be the cause of increased adsorption capacity.…”

Arabica-coffee and teobroma-cocoa agro-industrial waste biosorbents, for Pb(II) removal in aqueous solutions

“…Therefore, the effective elimination of Pb from wastewater and in general, the investigation of heavy metal biosorption processes on biological surfaces or biosorbent materials (Beni and Esmaeili 2020) is highly current. We highlight the use of various agricultural byproducts as "cheap" biosorbents to remove Pb from aqueous solutions, such as olive tree pruning (Calero et al 2013), taro (Saha et al 2017), prickly pear stalk (Lavado-Meza et al 2020), sugar cane bagasse (Tejada-Tovar et al 2020), spent coffee grounds (Ayucitra et al 2017;Chwastowski et al 2020) coffee grounds (Minamisawa et al 2004;Gomez-Gonzalez et al 2016), coffee husk (Oliveira et al 2008), endocarp waste coffee (Gómez-Aguilar et al 2021;Mariana et al 2021), and untreated cocoa shells (Meunier et al 2003;Obike et al 2018). The use of these materials is attractive due to their availability and the low costs involved in treating contaminated water.…”