Systematic studies on the effect of structural modification of orange peel for remediation of phenol contaminated water

Abstract

In the present study, orange peel biochar has been utilized as the adsorbent for the removal of phenol from contaminated water. The biochar was prepared by thermal activation process at three different temperature 300, 500 and 700°C and are defined as B300, B500, and B700 respectively. The synthesized biochar has been characterized using scanning electron microscopy (SEM), X‐ray diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR), RAMAN spectroscopy, X‐ray photoelectron spectroscopy (XPS), and UV–Vis spectroscopy. SEM analysis revealed a highly irregular and porous structure for B700 as compared with others. The parameters such as initial phenol concentration, pH, adsorption dosage, and contact time were optimized, and the maximum adsorption efficiency and capacity of about 99.2% and 31.0 mg/g was achieved for B700 for phenol adsorption. The Branauer‐Emmett‐Teller (BET) surface area and Berrate–Joyner–Halenda (BJH) pore diameter obtained for B700 were about 67.5 m2/g and 3.8 nm. The adsorption of phenol onto the biochar followed Langmuir isotherm showing linear fit with R2 = 0.99, indicating monolayer adsorption. The kinetic data for adsorption is best fitted for pseudo‐second order. The thermodynamic parameters ΔG°, ΔH°, and ΔS° values obtained are negative, which means that the adsorption process is spontaneous and exothermic. The adsorption efficiency of phenol marginally declined from 99.2% to 50.12% after five consecutive reuse cycles. The study shows that the high‐temperature activation increased the porosity and number of active sites over the orange peel biochar for efficient adsorption of phenol. Practitioner Points Orange peel is thermally activated at 300, 500, and 700°C for structure modification. Orange peel biochars were characterized for its structure, morphology, functional groups, and adsorption behavior. High‐temperature activation improved the adsorption efficiency up to 99.21% due to high porosity.

Acetaminophen Adsorption on Carbon Materials from Citrus Waste

“…The surface area values found in this work are lower than most of the activated carbons. However, these values are in the order of other carbon adsorbents obtained from different natural residues reported in the literature: da Silva et al [5] found surface area values in the range 166-400 m 2 /g for carbons obtained from citrus fruit residues, Verma et al [11] found values of 207 m 2 /g and 37 m 2 /g for carbon adsorbents derived from waste biomass of citrus limetta (peel and pulp), Kumar et al [6] found 67.5 m 2 /g for biochars obtained from orange peel residues, Ahmadian et al [2] found 195 m 2 /g for biochars obtained from lemon peel and Aboli et al [50] found 7.2 m 2 /g for carbons prepared from citrus limetta leaves. It should be remarked that the impregnation step, the mixture of the carbonaceous precursor with FeCl 3 , is usually performed by two different methods: in an aqueous solution or by physical mixing between the carbon precursor and the iron chloride activating agent.…”

“…Nowadays, agricultural and food processing activities generate huge amounts of solid wastes, which are commonly eliminated by burning, bringing on different ecological and environmental problems [1]. Agricultural waste is cheap, and it includes husks, peels, and shells of different crops such as rice, sunflower, palm, citric, or different kinds of nuts [2][3][4][5][6]. Most of this waste contains such compounds as starch and lignocellulosic biomass including cellulose, hemicellulose, and lignin [7,8], all of them with a high content of carbon, and were easily transformed into activated carbons or biochar under pyrolysis processes [9,10].…”