Activated carbon produced from Glycyrrhiza glabra residue for the adsorption of nitrate and phosphate: batch and fixed-bed column studies

Abstract

In the present study, Glycyrrhiza glabra residues (GGR) were used for the preparation of activated carbon, with a surface area of 959.22 m 2 g −1 . Activated carbon was prepared through chemical activation using ZnCl 2 at optimum carbonization temperature, and impregnation ratio for nitrate, and phosphate removal. The effect of contact time and adsorbent dosage on the removal efficiency was investigated, and the pseudo-second-order kinetic model correlated well with the adsorption data. The response surface methodology was applied for the determination of the effect of initial concentration, pH, and temperature and their interaction on the removal efficiency in the batch adsorption system. The Langmuir isotherm generated a satisfactory fit with the experimental data, and the maximum adsorption capacity was 142.5 mg g −1 at 308 K and 92.5 mg g −1 at 298 K for nitrate and phosphate removal, respectively. The high adsorption capacity reveals the applicability of the GGR activated carbon for nitrate and phosphate removal. Furthermore, the fixed-bed column adsorption studies were carried out, and the effect of flow rate and influent concentration on the behavior of the breakthrough curve was studied. The breakthrough time decreased by increasing the flow rate and inlet concentration. The Thomas and Yoon-Nelson models were suitable models for the design of GGR activated carbon fixed-bed column. The LUB of 0.44 cm and 4.35 cm was obtained for nitrate and phosphate with the inlet concentration of 20 mg L −1 and a flow rate of 40 mL min −1 , respectively. GGR is a new adsorbent that has not been previously utilized for adsorption of phosphate and nitrate.

Cd2+ removal efficiency of activated carbon from Prosopis juliflora: Optimization of preparation parameters by the Box-Behnken Design of Response Surface Methodology

“…As a result, the oxygen from phenol which is now hydrogen atom free would introduce a pair of electrons into the vacant orbital of Zn [ 44 ]. As explained by both [ 45 , 46 ], ZnCl 2 possesses two Cl; therefore, it can react with two phenol-containing structures to create cross-links. Since the ZnCl 2 forms cross-links and creates a stiff matrix, raising the ZnCl 2 ratio would result in higher Cd 2+ removal efficiency until IR 1.7 as shown in Fig.…”

“…The high Cd 2+ removal efficiencies with increasing carbonization temperature was attributed to increase in both micro and mesopores. A porous structure develops because at higher carbonization temperatures there is release of more volatile chemicals [ 45 ]. Temperatures above 450 °C can cause an increase in porosity due to the development of tar, which occurs when lignocellulosic material is treated with acid [ 47 ].…”

Sonocrystallization of a novel ZIF/zeolite composite adsorbent with high chemical stability for removal of the pharmaceutical pollutant azithromycin from contaminated water

“…According to the study, mass transfer on the outer surface controls the first stage of adsorption. On the contrary, the sharp increment in adsorption within the method's early stages was considered a quick stage for starting the mass transfer [24] .…”

“…Researchers used the simulation methods to adsorb drugs [20] , [21] . Various methods, such as membrane, adsorption, ozonation, and advanced oxidation processes (AOP) were used to remove the medicinal compounds from water [22] , [23] , [24] , [25] . The materials, such as activated carbon, metal–organic frameworks (MOFs), and polymeric adsorbents have a high particular surface area, and permeable structure, and are modifiable, which can be compelled in specific execution, and expulsion of contaminants [26] .…”

Removal of copper and zinc in metal working fluid using coconut composite filter media

“…The surface morphology was conducted by Scanning Electron Microscopy (SEM) Hitachi TM3030 Plus. Functional group of the adsorbent [10] was recorded using Fourier Transform Infrared (FTIR) Niclet 6700 FT-IR.…”