Adsorption Performance of Low-cost Java Plum Leaves and Guava Fruits as Natural Adsorbents for Removal of Free Fatty Acids from Coconut Oil

Abstract

A B S T R A C TThis study assesses the adsorption performance of Java plum leaves and guava fruits based adsorbents as natural products widely available in Aceh, Indonesia. These renewable adsorbents were employed to remove free fatty acids (FFAs) that cause the rancid odor in coconut oil. The adsorption tests were carried out at three different doses (50, 75, 100 g) and seven agitating periods (1, 2, 3, 4, 5, 6, 7 h). The adsorbents were characterized by Scanning Electron Microscopy (SEM) to observe their morphologies, and Fourier transform infrared (FTIR) spectroscopy to investigate the functional groups. The adsorption kinetics were also analyzed using the Freundlich and Langmuir isotherm models. The SEM image showed that the particle sizes of the guava fruits based adsorbent were 30-45 µm while those of Java plum leaves based adsorbent were 7-15 µm, both showing attractive range to enhance surface area for adsorption sites. FTIR spectra showed the presence of methylene, aliphatic and phenolic groups for both absorbent, aromatic and alkene groups only for java plum based adsorbent and secondary amine and alcohol groups only for guava fruit based adsorbent. Those groups seem to play important role in enhancing chemical adsorption of FFAs from the coconut oil sample. The results showed that Java plum leaves and guava fruits based adsorbents had a respective maximum adsorption capacity of 144.99 and 133.77 mg/g, with an optimum agitation time of 6 hour. The high absorption capacity could be ascribed from phenolic and flavonoid compounds present in both materials. Kinetics of adsorption of FFAs on both materials obeyed the Freundlich isotherm model indicating a multilayer and heterogeneous surface of adsorbent.

Gasification of Psidium guajava L. Waste Using Supercritical Water: Evaluation of Feed Ratio and Moderate Temperatures

“…The weak peak observed at 1143 cm −1 presented aromatic C-H in plane bending, OH and C=O stretches [56,65]. The weak shoulder absorption band observed at 1098 cm −1 could be attributed to the C-O-H bending modes and C-O, suggesting the presence of alcohol groups [58,66] [50,52,55,65]. The 923 cm −1 weak signal indicated C-H out of plane for alkane group and aromatic [56,68].…”

“…The CH 2 asymmetrical and symmetrical stretching for alkane groups were associated with the medium peak at 2921 cm −1 and the weakness signal at 2850 cm −1 , respectively [47,52,53]. The weak peak around 1730 cm −1 corresponded to the carbonyl C=O stretching vibration of different groups such as acetyl, aldehydes, ketones and carboxylic acids [47,50,55,56]. The stretch of the carbonyl (C=O) conjugated with the aromatic skeleton of phenylpropane appeared for the medium signal at 1600 cm −1 of wavelength [55][56][57][58].…”

“…Guava samples were also analyzed by Fourier Transform Infrared spectroscopy, a representative spectrum is illustrated in Figure 3 where the adsorption bands were associated with the functional groups of complex compounds. Emphasis was made on the polysaccharides listed in Table 2 as cellulose, hemicellulose, and lignin, but the samples also contained other components identified elsewhere like pectin, proteins, and flavonoids [47][48][49][50]. The strong broad peak at 3273 cm −1 denoted the phenolic and aliphatic hydroxyl group stretching vibration; NH stretching of the amine group indicated the amino acid components [50][51][52][53][54].…”

“…Emphasis was made on the polysaccharides listed in Table 2 as cellulose, hemicellulose, and lignin, but the samples also contained other components identified elsewhere like pectin, proteins, and flavonoids [47][48][49][50]. The strong broad peak at 3273 cm −1 denoted the phenolic and aliphatic hydroxyl group stretching vibration; NH stretching of the amine group indicated the amino acid components [50][51][52][53][54]. The CH 2 asymmetrical and symmetrical stretching for alkane groups were associated with the medium peak at 2921 cm −1 and the weakness signal at 2850 cm −1 , respectively [47,52,53].…”

Synergetic photocatalytic and adsorptive removals of metanil yellow using TiO2/grass-derived cellulose/chitosan (TiO2/GC/CH) film composite

“…All the following studies employed the optimum adsorption parameters obtained earlier (100 minutes contact time; pH 3). Adsorption capacity at t time (qt (mg/g)), adsorption capacity at equilibrium (qe (mg/g)), and removal percentage (%) were calculated based on the equations we had used in the previous reports [35][36][37]. For the photodegradatino using UV irradiation, a UV lamp (6 W; λ = 365 nm) was used and positioned 10 cm away from the batch container.…”