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Highlights: [•] FeCl3, AlCl3 and MnCl2 were used as the assisted activator to produce carbons. [•] Doping with MnCl2 was favorable for the enlargement of activated carbon. [•] The assisted activator had good performance for holding more fixed carbon. [•] The maximum adsorption capacities followed the order of AC-Fe>AC-Al>AC-Mn>AC. [•] The XPS analysis was used to confirm the adsorption/transformation mechanism. [Copyright &y& Elsevier]

Abstract: Preparation of highly developed mesoporous activated carbons from renewable source Arundo donax Linn was performed using H4P2O7 as activator. The influences of chemical impregnation ratio (mass of H4P2O7:A. donax Linn), activation temperature and soaking time on the properties (yield, BET surface area, pore volume and surface functional group) of activated carbon were investigated. The optimal activated carbon (ALAC) was characterized by scanning electron micrograph (SEM), N2 adsorption/desorption isotherms, X-ray photoelectron spectrometry (XPS) and oxytetracycline (OTC) adsorption experiments. Results showed that the pore development was significant at temperatures >400°C, and reached a maximum BET surface area (1463m2/g) at 600°C and maximum total pore volume (1.24cm3/g) at 500°C. At a low impregnation ratio of 0.4, BET surface area and pore volume could reach as high as 1150.69m2/g and 0.59m3/g. Both BET surface area and pore volume initial increase followed by a decrease after reaching a maximum, with the maximal surface area was obtained at an impregnation ratio of 0.75 and maximal pore volume at 1.0. BET surface area and mesopore volume reached maximum after 10h of soaking. Acidic surface groups followed the order of: strong acidic groups>weak acidic groups>intermediate acidic groups. Low activation temperature was favorable to the formation of acidic surface functional groups. With the increase of soaking time, the acidic surface functional initial increase was followed by a gradual decrease and finally tended to level off. [Copyright &y& Elsevier]

Abstract: The objective of this research is to produce high surface area–activated carbon derived from cotton linter fibers by fused NaOH activation and to examine the feasibility of removing oxytetracycline (OTC) from aqueous solution. The cotton linter fibers activated carbon (CLAC) was characterized by N2 adsorption/desorption isotherms, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscope (SEM). The results showed that CLAC had a predominantly microporous structure with a large surface area of 2143m2/g. The adsorption system followed pseudo-second-order kinetic model, and equilibrium was achieved within 24h. The equilibrium data were described well by Langmuir isotherm. Thermodynamic study showed that the adsorption was exothermic reaction at low concentration and became endothermic nature with the concentration increasing. Competitive adsorption took place in the weakly acidic to neutral conditions. Under the strong acidity or strong alkaline condition, the adsorption of the oxytetracycline was hindered by electrostatic repulsion. The adsorption mechanism depended on the pH of the solutions as well as the pK a of the oxytetracycline. [Copyright &y& Elsevier]

Abstract: Two activated carbons employing Cyperus alternifolius as precursor were produced by using two different activating agents, H3PO4 and H4P2O7 (AC-H3PO4 and AC-H4P2O7). Both of activated carbons were allowed by single-step to get carbonized at 450°C in a muffle furnace for 1h. Activated carbons differed with the physical structure and chemical properties which were derived from Scanning Electron Microscope, N2 adsorption/desorption isotherms and Fourier-transform infrared spectroscopy (FTIR). Batched sorption studies were performed to compare the ciprofloxacin (CIP) adsorption properties of two carbons. The results indicated that AC-H3PO4 had 1066.4m2/g of surface area and 1.151cm3/g of total pore volume, while AC-H4P2O7 had 1040.3m2/g of surface area and 1.227cm3/g of total pore volume. Moreover, AC-H4P2O7 exhibited a higher portion of mesopores than AC-H3PO4. Fourier transform infrared spectra indicated two samples had similar functional groups. For both adsorbents, the adsorption kinetics followed the pseudo-second-order model. The adsorption equilibrium data were very well represented by three commonly used isotherm model for AC-H3PO4 (Langmuir, Freundlich and Temkin equations). As for AC-H4P2O7, the adsorption isotherm models fitted the data in the order: Langmuir>Temkin>Freundlich isotherms. The thermodynamic parameters indicated that the adsorption of CIP onto both adsorbents was spontaneous and thermodynamically favorable, with exothermic nature of the adsorption of CIP onto AC-H3PO4 and endothermic nature onto AC-H4P2O7. [Copyright &y& Elsevier]

Highlights: [•] Enteromorpha prolifera-based activated carbon was activated by KOH and H4P2O7. [•] The properties of carbons prepared by H4P2O7 and KOH were compared. [•] The activated carbon with high surface area of 3500m2/g was prepared by KOH. [•] The prepared carbons exhibited significant adsorption capacity for GR. [ABSTRACT FROM AUTHOR]