Carbonization of corn (Zea mays) cob agricultural residue by one-step activation with sulfuric acid for methylene blue adsorption

Abstract

a b s t r a c tCorn (Zea mays) cob, an agricultural biomass residue, was carbonized by chemical activation with H 2 SO 4 and examined for its suitability as a low-cost adsorbent for methylene blue (MB) adsorption from aqueous solution. Carbonized corn cob (CCC) was characterized by a CHNS-O analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction (XRD), Brunauer-Emmett-Teller, and point-of-zero charge (pH pzc ) analysis. Batch mode adsorption studies were conducted by varying operational parameters such as adsorbent dosage (0.02-0.20 g), solution pH (3-10), initial MB concentrations (50-300 mg/L), and contact time (0-360 min). The equilibrium data were well correlated by the Freundlich isotherm compared with Langmuir and Temkin models. The maximum adsorption capacity (q max ) of CCC for MB adsorption at equilibrium was 216.6 mg/g at 303 K. The kinetic uptake profiles were well-described by the nonlinear pseudo-first-order model. The thermodynamic adsorption parameters such as standard enthalpy (ΔH°), standard entropy (ΔS°), and standard free energy (ΔG°) showed that the adsorption of MB onto CCC surface is endothermic in nature and spontaneous under the experimental conditions. The above-mentioned results indicate that the CCC can be feasibly employed for the removal of MB from aqueous solution.

Facile synthesis of corncob biochar via in-house modified pyrolysis for removal of methylene blue in wastewater

“…The elemental composition and physical parameters of the corncob biomass and the biochar are given in table 1. The results show that carbon is the major constituent (C 80.60%wt) of corncob biochar, which confirms its carbonaceous nature compared to previous carbonized corncob prepared using acid (C 49.87%wt) [30]. The obtained biochar has a high fix-carbon content of 76%wt and a small ash content of 5%wt, which is low among plants biomasses [31,32].…”

Incorporation of metallic particles in activated carbon used in lipase immobilization for production of isoamyl acetate

“…The point of zero charge (pH PZC ) is one of the properties that must be evaluated in adsorbents, as it is related to the surface charge and is a function of the activation method used. The pH PZC can be defined as the pH value in which there is no net charge on the solid surface; 47 i.e., at solution pH above the pH PZC value, the surface of the support is positively charged and thus adsorption of anions is favored, whereas adsorption of cations is preferred at a solution pH below the pH PZC value 48 . The pH PZC of CCAC was 4.5, owing to the presence of acid groups formed on the support surface by the activating agent 32 .…”

“…The pH PZC can be defined as the pH value in which there is no net charge on the solid surface; 47 i.e., at solution pH above the pH PZC value, the surface of the support is positively charged and thus adsorption of anions is favored, whereas adsorption of cations is preferred at a solution pH below the pH PZC value. 48 The pH PZC of CCAC was 4.5, owing to the presence of acid groups formed on the support surface by the activating agent. 32 For the CCACM sample an increase in the value of pH PZC to 7.4 was observed; this can be attributed to the methodology used to incorporate metallic particles, in which the activated carbon was brought into contact with the acidic solution of Fe 2+ and Fe 3+ salts, followed by the addition of NaOH solution, which raised the pH, favoring neutralization of the functional groups on the material surface.…”

Enhancement the rhodamine 6G adsorption property on Fe3O4-composited biochar derived from rice husk

“…However, at the low-pyrolysis temperature at 400°C, the carbonouse biochar was obtained in higher yield with the higher oxygen and volatile-matter components, compared to the biochar produced at the high-temperature pyrolysis. The increasing pyrolysis temperature reduced biochar yield and its volatiles content [30,31]. At increasing temperature of pyrolysis (500 and 600 o C), the percentage of carbon is increased and oxygen content is obviously decreased.…”