Effect of activated carbon produced from biochar on removal of 2, 4-dichlorophenoxy acetic acid from aqueous solutions

701-708The toxicity of pesticides and their degradation products is making these chemical substances a potential hazard by contaminating our environment. Therefore, the removal of pesticides from water is one of the major environmental concerns these days. 2,4-Dichlorophenoxy acetic acid (2,4-D) belonging to the herbicide group, which is among the numerous pesticides used today, is widely used to control weeds due to its low cost and good selectivity. In order to offer an alternative to this environmental problem, the effect of activated carbon obtained by chemical activation from pyrolysis biochar on 2,4-dichlorophenoxy acetic acid removal from aqueous solutions has been investigated. The adsorption mechanism is explained by analyzing the effect of adsorption parameters. It is determined that the equilibrium data are suitable for Langmuir isotherm model among the applied isotherm models and the monolayer adsorption capacity is 344.83 mg g-1 at 318 K. The adsorption kinetics data of 2,4-D on activated carbon is better defined by the pseudo-second-order model. Thermodynamic calculations reveal that the adsorption process is spontaneous and endothermic. The activated carbon obtained from biochar has been observed to have a high adsorption capacity compared to adsorbent materials obtained from many other raw materials for the removal of 2,4-Dichlorophenoxy acetic acid

Effect of pyrolysis temperature and heating rate on biochar obtained from pyrolysis of safflower seed press cake

Biochar is carbon-rich product generated from biomass through pyrolysis. In this study, the effects of pyrolysis temperature and heating rate on the yield and physicochemical and morphological properties of biochars obtained from safflower seed press cake were investigated. The results showed that the biochar yield and quality depend principally on the applied temperature where pyrolysis at 600 degrees C leaves a biochar with higher fixed carbon content (80.70%) and percentage carbon (73.75%), and higher heating value (30.27 MJ kg(-1)) in comparison with the original feedstock (SPC) and low volatile matter content (9.80%). The biochars had low surface areas (1.89-4.23 m(2)/g) and contained predominantly aromatic compounds. The biochar could be used for the production of activated carbon, in fuel applications, and water purification processes. (C) 2012 Elsevier Ltd. All rights reserved

Utilization of activated carbon produced from fruit juice industry solid waste for the adsorption of Yellow 18 from aqueous solutions

The use of activated carbon obtained from sour cherry (Prunus cerasus L.) stones for the removal of a basic textile dye, which is Yellow 18, from aqueous solutions at different contact times, pH values and solution temperatures was investigated. The surface area and micropore volume of chemically modified activated carbon were 1704 m(2) g (1) and 0.984 cm(3) g (1), respectively. The experimental data indicated that the adsorption isotherms were well described by the Langmuir equilibrium isotherm equation and the calculated adsorption capacity was 75.76 mg g (1) at 318 K. The adsorption kinetic of Yellow 18 obeys the pseudo-second-order kinetic model. The thermodynamic parameters were calculated to estimate the nature of adsorption. The activation energy of the system was calculated as 0.71-2.36 kJ/mol. According to these results, prepared activated carbon could be used as a low-cost adsorbent to compare with the commercial activated carbon for the removal of Yellow 18 from wastewater. (C) 2014 Elsevier Ltd. All rights reserved

Production and characterization of activated carbon from sour cherry stones by zinc chloride

The purpose of this study is to produce the low-cost activated carbon from the sour cherry (Prunus cerasus L.) stones, known as a waste of fruit juice industry, by chemical activation using zinc chloride. The effects of the activation temperature and the impregnation ratio on the surface and chemical properties of activated carbon were investigated. Also, the mathematical correlation between the activation process variables and outputs such as activated carbon yield and surface area were examined by using the Response surface methodology. The activation temperatures and impregnation ratios were selected at the range of 500-900 degrees C and 1:1-4:1, respectively. In the study, it was observed that the optimum conditions for the activated carbon production were activation temperature of 700 degrees C and impregnation ratio of 3:1. The optimum conditions resulted in an activated carbon with a carbon content of 80.78% and a yield of 16.22%, while the Brunauer-Emmett-Teller surface area evaluated using nitrogen adsorption isotherm corresponds to 1704 m(2) g(-1), with the total pore volume of 1.566 cm(3) g(-1). The activated carbon was heteroporous with the micropore volume contributing to 62.84%. Also, experimental results showed that the activation temperature and the impregnation ratio have significant effects on the pore structure of the activated carbon and sour cherry stones seemed to be an alternative precursor for the commercial activated carbon productions. (C) 2013 Elsevier Ltd. All rights reserved

Production and characterization of activated carbon prepared from safflower seed cake biochar and its ability to absorb reactive dyestuff

The use of activated carbon obtained from biochar for the removal of reactive dyestuff from aqueous solutions at various contact times, pHs and temperatures was investigated. The biochar was chemically modified with potassium hydroxide. The surface area and micropore volume of activated carbon was 1277 m(2)/g and 0.4952 cm(3)/g, respectively. The surface characterization of both biochar and activated carbon was undertaken using by Fourier transform infrared spectroscopy and scanning electron microscopy. The experimental data indicated that the adsorption isotherms are well described by the Dubinin-Radushkevich (DR) isotherm equation. The adsorption kinetics of reactive dyestuff obeys the pseudo second-order kinetic model. The thermodynamic parameters such as Delta G degrees, Delta H degrees and Delta S degrees were calculated to estimate the nature of adsorption. The activation energy of the system was calculated as 1.12 kJ/mol. According to these results, prepared activated carbon could be used as a low-cost adsorbent to compare with the commercial activated carbon for the removal reactive dyestuff from wastewater. (C) 2013 Elsevier B.V. All rights reserved

EFFECT OF PYROLYSIS TEMPERATURE ON CHEMICAL AND SURFACE PROPERTIES OF BIOCHAR OF RAPESEED (BRASSICA NAPUS L.)

The biochar is an important carbon-rich product that is generated from biomass sources through pyrolysis. Biochar (charcoal) can be both used directly as a potential source of solid biofuels and as soil amendments for barren lands. The aim of this study was investigate influence of pyrolysis temperature on the physicochemical properties and structure of biochar. The biochars were produced by pyrolysis of rapeseed (Brassica napus L.) using a fixed-bed reactor at different pyrolysis temperatures (400-700 degrees C). The produced biochars were characterized by proximate and elemental analysis, Brunauer-Emmett-Teller (BET) surface area, particle size distributions, scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy. The results showed that both chemical and surface properties of the biochars were significantly affected by the pyrolysis temperature.Aromatic hydrocarbons, hydroxyl and carbonyl compounds were the majority components of the biochar. The biochar obtained at 700 degrees C had a high fixed carbon content (66.16%) as well as a high heating value, and therefore it could be used as solid fuel, precursor in the activated carbons manufacture (specific surface area until 25.38m(2) g(-1)), or to obtain category-A briquettes