Retention Profile of Zn<sup>2+</sup> and Ni<sup>2+</sup> Ions from Wastewater onto Coffee Husk: Kinetics and Thermodynamic Study

Abstract

In this work, Coffee husk (CH) was used as a solid phase extractor (SPE) for removal and/or minimization of Zn 2+ and Ni 2+ ions in aqueous media. XRD, FESEM and FTIR analysis of the SPE were performed for surface morphology and function groups characterisation. Batch mode adsorption studies were performed by varying the operational parameters such as adsorbent dose, solution pH, initial analyte concentration and contact time. The equilibrium data of both analytes was found a better fit with the Langmuir and Freundlich isotherm models. The q m of Langmuir for Zn 2+ and Ni 2+ ions were 12.987 and 11.11 mg/g, respectively. The adsorption capacities of the CH adsorbent towards Zn 2+ and Ni 2+ resulted of 12.53 and 10.33 mg/g, respectively. In addition, the kinetic data of Zn 2+ and Ni 2+ ions uptake revealed that the present system fitted well with pseudo-second-order kinetic model (R 2 > 0.99). Thermodynamic studies showed that the retention step was exothermic, and spontaneous in nature. The results indicated that the coffee husk provides an effective and economical approach in highly reducing or almost eradication of both metals Zn 2+ and Ni 2+ from the aqueous solution.

Applicability of Natural Coffee Husk as a Mesoporous Adsorbent for Removal of Chromium (VI) from Aquatic Environments

“…The existence peak at 3255-3504 cm -1 , corresponding to free hydroxyl groups from carboxylic acids, phenols, and alcohols, which are associated with cellulose and lignin (Tursi et al, 2022). This result is comparable to that from an earlier investigation where the peak at 3421.57 cm -1 , showing that the adsorbent surface contains free hydroxide groups (Alhogbi & Al-Enazi, 2018, Liu et al, 2007. Meanwhile, the stretching bonds -CH 2 , C-C, C-O, and C-N were responsible for the adsorption peaks at 2952, 1650, 1425, 1228, and 870 cm -1 , respectively.…”

“…The amorphous coffee husk surface has a rough cavity shape and comes in a variety of sizes. It can be examined using a scanning electron microscope (Alhogbi & Al-Enazi, 2018). Before adsorption, the FTIR spectrometer was used to investigate the vibrational and bending spectrum functional groups of coffee husk, as shown in Figure 1 (c).…”

Process optimisation of methylene blue sequestration onto physical and chemical treated coffee husk based adsorbent

“…The peaks located at 1746 and 1628 cm −1 are attributed to stretching vibrations of aldehydes and ketones, and peak at 1429 cm −1 can be assigned to carboxyl group C-O bond stretching vibration. Peaks at 1248 and 1437 cm −1 correspond to C-N stretching vibration of the amine group and O-H bending vibration of the carboxylic group, respectively [43][44][45][46][47][48].…”

Agro waste material as ecofriendly adsorbent for the removal of Zn(II): isotherm, kinetic, thermodynamic and optimization studies

“…Problems of generation of secondary impurity can also be overcome by the use of natural biosorbents that produce minute solid wastes that can be disposed in landfill or easily managed by incineration [17]. The conversion of agro-waste to useful biomaterial has added different dimension to the utilization of agricultural waste for value added products Many agricultural and biological based materials have been utilized as biosorbent for the removal of Zn 2+ from aqueous media, these include; coconut husk [18]; orange residue [19]; sea weeds [20], maize leaf [21], coffee husk [22], coffee residue [23], wheat straw [24], corn silk [25], tea waste [26] and Plantain stalk [27] to mention but few. Nigeria is the third largest producer of groundnut with about 3.0 million metric tonne per annum [28].…”