Iron-Loaded Pomegranate Peel as a Bio-Adsorbent for Phosphate Removal

Abstract

This study investigated the adsorption of phosphate from aqueous solutions using pomegranate peel (PP) as a bio-adsorbent. For this purpose, PP was activated via saponification using sodium hydroxide (NaOH) followed by cationization using iron chloride (FeCl3). The iron-loaded PP (IL-PP) was characterized using zeta potential measurement, scanning electron microscopy, and Fourier transform infrared analysis. The batch adsorption method was followed to determine the equilibrium time and effect of pH on the adsorption process. The full factorial design methodology was used to analyze the effects of influencing parameters and their interactions. The effective removal of phosphate up to 90% was achieved within 60 min, at pH 9 and 25 °C temperature using a 150 mg dose of IL-PP. A non-linear method was used for the modeling of isotherm and kinetics. The results showed that the kinetics is best fitted to the Elovich model (R2 = 0.97), which assumes the dominance of the chemisorption mechanism, whereas the isotherm obeys both Langmuir (R2 = 0.98) and Freundlich (R2 = 0.94) models with a maximum phosphate uptake of 49.12 mg·g−1. Investigation of thermodynamic parameters indicated the spontaneity and endothermic nature of the process. These results introduce IL-PP as an efficient bio-adsorbent of phosphate.

Phytotoxicity evaluation of nutrient-fortified pomegranate peel powders prepared from food waste and their feasibility as biofertilizers

“…Next, oven-dried PP (105 °C, 2 h) was powdered in a grinder (particle size < 250 µm), resulting in a material referred to as raw PPP (hereafter Raw-PPP) (Bellahsen et al, 2021b). Raw-PPP was further used to prepare N-fortified (N-PPP) and P-fortified PPP (P-PPP) by adsorbing ammonium nitrogen and phosphate, respectively, from milking parlor unit (located near Szeged, Hungary) wastewater according to methods described by Hodúr et al (2020) and Bellahsen et al (2021a). The detailed methodology and the characterization of both the wastewater and prepared PPPs have been described in our previous studies (Hodúr et al, 2020;Bellahsen et al, 2021aBellahsen et al, , 2021b.…”

“…Raw-PPP was further used to prepare N-fortified (N-PPP) and P-fortified PPP (P-PPP) by adsorbing ammonium nitrogen and phosphate, respectively, from milking parlor unit (located near Szeged, Hungary) wastewater according to methods described by Hodúr et al (2020) and Bellahsen et al (2021a). The detailed methodology and the characterization of both the wastewater and prepared PPPs have been described in our previous studies (Hodúr et al, 2020;Bellahsen et al, 2021aBellahsen et al, , 2021b. We also prepared Mix-PPP containing a 1:1 mixture of N-PPP and P-PPP.…”

“…Interestingly, the individual changes within the same PPP treatment group appeared to be dependent on the dosage with Raw-PPP and N-PPP additions, larger leaves were detected with increasing PPP concentrations, but with P-PPP and Mix-PPP additions, the largest leaves were observed at medium PPP concentrations. These different tendencies (although not always supported by ANOVA) might be explained by the differences in the production processes of N-PPP and P-PPP: To improve its phosphate adsorption and retention ability, P-PPP was activated with iron chloride (FeCl 3 ) during production (Bellahsen et al, 2021a). Although iron is an essential micronutrient for plant development, excess iron can cause toxicity and disrupt cell homeostasis, resulting in tissue damage (Santana et al, 2014).…”

“…PP waste is traditionally utilized as animal feed; however, there is an increasing interest on novel PP valorization techniques such as the production of value-added products (e.g., essential oils, pectin, reducing sugars, dietary fibers, and cosmetic and medical products) or the recirculation of PP waste in biorefinery processes (e.g., biogas, bioethanol, and biohydrogen). More recently, PP is also used as a soil amendment or bioadsorbent (Bellahsen et al, 2021a(Bellahsen et al, , 2021bEl Barnossi et al, 2021;Roukas & Kotzekidou, 2020) as it contains a substantial variety of functional groups (e.g., -OH and -COH), ensuring its exceptional ion exchange capacity and general adsorptive characteristics (Bellahsen et al, 2021b). Considering that biomass waste-derived bioadsorbents can be renewable, easily produced, cost-efficient, and sustainable, their application promises encouraging results in the fields of bioremediation, waste management, and water purification (Solangi et al, 2021).…”

“…Considering that biomass waste-derived bioadsorbents can be renewable, easily produced, cost-efficient, and sustainable, their application promises encouraging results in the fields of bioremediation, waste management, and water purification (Solangi et al, 2021). Recent studies have demonstrated that pomegranate peel powders (PPPs) can be used to remove ammonium nitrogen (81.8% efficiency with the initial NH 4 -N concentration of 80 mg/L) (Hodúr et al, 2020) or phosphate phosphorus (90% efficiency with the initial PO 4 -P concentration of 40 mg/L) (Bellahsen et al, 2021a) from wastewaters. Such treatments not only prevent severe environmental ramifications (e.g., overfertilization of soils and eutrophication of water bodies) but also improve the chemical characteristics of adsorbents.…”