Removal of 2.4-dichloro phenoxyacetic acid from aqueous solution by adsorption on activated carbon. A kinetic study (original) (raw)
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Chemical Industry, 2019
Lagenaria vulgaris activated carbon (LVAC) was synthesized from Lagenaria vulgaris biomass by treatment with diluted H2SO4 followed by thermo-chemical carbonization and overheated steam activation process and used for removal of the herbicide 2,4-dichlo-rophenoxyacetic acid (2,4-D). Fourier transform infrared spectroscopy (FTIR) indicated that 2,4-D is adsorbed in micropores of the very porous LVAC (665 m2 g-1). LVAC showed high sorption capacity as compared to many previously used sorbents at optimal conditions: the stirring rate of 300 rpm, the sorbent dose of 1.0 g dm-3 and pH from 2 to 7. The experimental maximum sorption capacity of LVAC was 333.3 mg g-1. The pseudo-second-order model and Chrastil model described the 2,4-D sorption kinetics by LVAC. Thermodynamic studies have indicated that the sorption process was endothermic, spontaneous and physical in nature. LVAC was shown to be an ultrahighly efficient sorbent for removal of 2,4-D from groundwater, which could be also rec...
Engenharia Sanitaria e Ambiental
The herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) has been detected in water bodies worldwide, precluding their use for water supply. Despite this, scientific studies assessing the behavior of herbicides in water treatment systems are scarce, which motivated this study on 2,4-D removal. 2,4-D removal and its relationship with absorbance were investigated using a pilot system comprising coagulation, sedimentation, filtration, granular activated carbon (GAC) adsorption, and chlorinated disinfection. 2,4-D removal ranged from 15 to 64% after sedimentation, from negative values to 19% after filtration, and from 5 to 16% after chlorination, with total removal rates of 19 to 70%. Breakthrough curves showed an adsorption capacity of 0.70 mg g−1 GAC for a C/C0 ratio of 0.50 and a VTW/VGAC ratio of 3.598 for a breakthrough concentration of 30 ± 3 μg L−1. The positive correlation between absorbance and 2,4-D (R2 = 0.78) in the GAC column effluent indicated that absorbance can be used for e...
Adsorption equilibrium, kinetic of 2,4-dichlorophenoxy-acetic acid (2,4-D), one of the most commonly used phenoxy acid herbicides, onto different adsorbents such as granular activated carbon (GAC) and synthetic polymeric adsorbents XAD-7HP, XAD-1180 and XAD-4 were studied in aqueous solution in a batch system. Langmuir isotherm model was applied to experimental equilibrium data of 2,4-D adsorption depending on adsorbents used. Equilibrium data fitted very well to the Langmuir equilibrium model in the studied concentration range of 2, 4-D for all the adsorbents studied. Adsorption using GAC is very rapid in the first hour of contact where 70-80 % of the adsorbate is removed by GAC followed by a slow approach to equilibrium, whereas in case of polymeric adsorbents 60-65 % of the adsorbate is removed in the first 30 min which is then followed by a slow approach to equilibrium.
Journal of Contaminant Hydrology, 2018
In this study, commercial activated carbons (GAB and CBP) were successfully used for the removal of two phenoxy acetic class-herbicides, 4-chloro-2-methyl phenoxy acetic acid and 2.4-dichlorophenoxy acetic acid (MCPA and 2.4-D) from aqueous solution. The adsorbent materials were characterized, and their equilibrium adsorption capacity was evaluated. The results suggest that the microporous properties of GAB activated carbon enhanced the adsorption capacity, in comparison to CBP carbon. Thus, the increasing in the ionic strength favored the adsorption removal of both pesticides, indicating that electrostatic interactions between the pollutant and the adsorbate surface are governing the adsorption mechanism, but increasing pH values decreased adsorption capacity. Experimental data for equilibrium was analyzed by two models: Langmuir and Freundlich. Finally, computational simulation studies were used to explore both the geometry and energy of the pesticides adsorption.
Egyptian Journal of Chemistry
E NVIRONMENTAL pollution has turned out to be one of the serious problems for human , animals and environment at present because of acute toxicities and carcinogenic nature of the pollutants. A lot of organic and inorganic contaminations have been reported in water for example phenol, dyes and heavy metal toxic ions. Pomegranate peels were used as low cost biosorbent to remove organic (phenol& cationic and anionic dyes) and inorganic(Ni 2+) pollutants from industrial wastewater. The main goal of this work is to prepare a low cost acid activated carbon from waste pomegranate peels by thermal and acid activation. Two forms of these peels, dried powder (PP) and Activated carbon (ACPP) were used. ACPP are characterized by different techniques such as IR, XRD, surface area and approximate & elemental analysis. Adsorption process is occurred under some environmental conditions such as pH, temperature, initial concentration, dose of adsorbent and contact time. The Removal percent for the adsorption of all pollutants were (86.79, 84.15, 83.02, 81.44 %) for MB, Mo, Ni 2+ ,ph on acid activated carbon.Adsorption capacity of ACPP more than PP. Biosorption procedure was tested on the basis of isotherm and kinetic models. Thermodynamic parameters such as the changes of free energy, enthalpy, and entropy were also calculated. The results showed that the adsorption of dyes, phenol and metal onto surface of ACPP was an endothermic process that could be fitted with the Freundlich adsorption model and pseudosecond order model. The activated carbon could be regenerated and used for 3 adsorption desorption cycle until sorbtion capacity reach to less than 50% than initial sorption capacity.
Adsorption Science & Technology, 2022
Recent trends in adsorption of hazardous organic pollutants including Polyaromatic Hydrocarbons (PAHs), Chemical Oxygen Demand (COD), Pharmaceuticals, and Chemical Dyes in wastewater using carbonaceous materials such as activated carbon (AC) and biochar (BC) have been discussed in this paper. Utilization of biomass waste in the preparation of AC and BC has gained a lot of attention recently. This review outlines the techniques used for preparation, modification, characterization, and application of the above-mentioned materials in batch studies. The approaches towards understanding the adsorption mechanisms have also been discussed. It is observed that in the majority of the studies, high removal efficiencies were reported using biowaste adsorbents. Regarding the full potential of adsorption, varying values were obtained that are strongly influenced by the adsorbent preparation technique and adsorption method. In addition, most of the studies were concentrated on the kinetic, isothe...
2014
The determination and remediation of three phenolic compounds bisphenol A (BPA), ortho-nitrophenol (o-NTP), parachlorophenol (PCP) in wastewater is reported. The analysis of these molecules in wastewater was done using gas chromatography (GC)×GC time-of-flight mass spectrometry while activated carbon derived from maize tassel was used as an adsorbent. During the experimental procedures, the effect of various parameters such as initial concentration, pH of sample solution, eluent volume, and sample volume on the removal efficiency with respect to the three phenolic compounds was studied. The results showed that maize tassel produced activated carbon (MTAC) cartridge packed solidphase extraction (SPE) system was able to remove the phenolic compounds effectively (90.84-98.49 %, 80.75-97.11 %, and 78.27-97.08 % for BPA, o-NTP, and PCP, respectively). The MTAC cartridge packed SPE sorbent performance was compared to commercially produced C18 SPE cartridges and found to be comparable. All the parameters investigated were found to have a notable influence on the adsorption efficiency of the phenolic compounds from wastewaters at different magnitudes.
Adsorption by charcoal is one of the efficient and economic methods used for the treatment of pharmaceutical effluents. In the current study, activated carbon was prepared from jute sticks and the reduction in chemical oxygen demand level of pharmaceutical effluent was determined. Jute sticks were washed and grounded to 1 mm particle size. It was chemically activated by using phosphoric acid and its surface area was determined. The chemical oxygen demand (COD) level of effluent taken from a pharmaceutical company in Kathmandu was determined. The reduction of COD level by the charcoal prepared from jute sticks was determined and compared with that reduced by the commercial sample. The experimental equilibrium data was correlated using Freundlich and Langmuir adsorption isotherm. The COD of the effluent sample was found to be 224 mg/L. The COD level was reduced to 188 mg/L and 96 mg/Ls by 0.1 g and 0.5 g respectively of Self Prepared Charcoal (SPC) whereas the COD level was reduced to 196 mg/L and 108 mg/L by 0.1 g and 0.5 g respectively of Commercial Charcoal (CC). The COD removal efficiency was found to be 57.14% and 51.78% with 0.5g of SPC and CC respectively. The study showed that activated charcoal can be successfully prepared from jute sticks and can be successfully used to reduce the COD level in pharmaceutical effluents and is more effective than commercial charcoal available in the market.
Asian Journal of Chemistry, 2013
Sorption studies were carried out to investigate removal of 2.4-dichlorophenol (2.4-DCP) from aqueous solution in a fl uidized bed by two types of adsorbent mixtures: BC (Bamboo char plus Calcium sulphate), and HBC (Hydroxyapatite plus Bamboo char plus Calcium sulphate); both manufactured in ball shape. The main material bamboo char was characterized by FTIR, DTA and SEM. The adsorption experiments were conducted in a fl uidized bed circulation column. Adsorption, isotherms and kinetic studies were established under 180 min operating process time, at different initial 2.4-DCP solution concentrations ranging from 5-10 mg/L, and at different fl ow rates ranging from 0.25-0.75 L/min. The data obtained fi tted well for both the Langmuir and Freundlich isotherm models; indicating favorable condition of monolayer adsorption. The kinetics of both adsorbents complies with the pseudo second-order kinetic model. BC was proven a new effective composite and low cost adsorbent which can be applied in the fi eld of wastewater treatment, and it can also play an important role in industry water treatment.
Journal of Environmental Health Science and Engineering, 2013
The phenolic compounds are known by their carcinogenicity and high toxicity as well as creating unpleasant taste and odor in water resources. The present study develops a cost-effective technology for the treatment of water contaminated with phenolic compounds, including Phenol (Ph), 2-chlorophenol (2-CP), and 4-chlorophenol (4-CP). So, two sorbents, rice bran ash (RBA) and biomass of brown algae, Cystoseiraindica, were used and results were compared with the commercially granular activated carbon (GAC). The phenolic compounds were determined using a high performance liquid chromatography (HPLC) under batch equilibrium conditions. The effects of contact time, pH, initial adsorbate concentration, and adsorbent dosages on the removal efficiency were studied. The adsorption data were simulated by isotherm and kinetic models. Results indicated that RBA and GAC had the lowest efficiency for the removal of 2-CP, while the order of removal efficiency for C. indica biomass was as follows: 2...