scholarly journals Poly(β-cyclodextrin)-Activated Carbon Gel Composites for Removal of Pesticides from Water

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1426
Author(s):  
Gianluca Utzeri ◽  
Luis Verissimo ◽  
Dina Murtinho ◽  
Alberto A. C. C. Pais ◽  
F. Xavier Perrin ◽  
...  

Pesticides are widely used in agriculture to increase and protect crop production. A substantial percentage of the active substances applied is retained in the soil or flows into water courses, constituting a very relevant environmental problem. There are several methods for the removal of pesticides from soils and water; however, their efficiency is still a challenge. An alternative to current methods relies on the use of effective adsorbents in removing pesticides which are, simultaneously, capable of releasing pesticides into the soil when needed. This reduces costs related to their application and waste treatments and, thus, overall environmental costs. In this paper, we describe the synthesis and preparation of activated carbon-containing poly(β-cyclodextrin) composites. The composites were characterized by different techniques and their ability to absorb pesticides was assessed by using two active substances: cymoxanil and imidacloprid. Composites with 5 and 10 wt% of activated carbon showed very good stability, high removal efficiencies (>75%) and pesticide sorption capacity up to ca. 50 mg g−1. The effect of additives (NaCl and urea) was also evaluated. The composites were able to release around 30% of the initial sorbed amount of pesticide without losing the capacity to keep the maximum removal efficiency in sorption/desorption cycles.

2002 ◽  
Vol 46 (11-12) ◽  
pp. 51-56 ◽  
Author(s):  
G.-W. Li ◽  
H.-Y. Hu ◽  
J.-M. Hao ◽  
H.-Q. Zhang

The biodegradation of toluene and benzene in a biofilter using cylindrical activated carbon as the filler materials was studied. Three gas flow rates, i.e. 0.25, 0.50 and 0.75 m3/h, corresponding to empty bed gas residence of 75, 37.5 and 25 s, respectively, and total organic load lower than 400 g/m3.h were tested. The biofilter proved to be highly efficient in biodegradation of toluene and benzene, and toluene was more easily degraded than benzene. When each inlet load was lower than 150 g/m3.h, removal rate increased with inlet load and reached a maximum, which was 150 and 120 g/m−3.h for toluene and benzene, respectively. For inlet load higher than the maximum removal capacity conditions, the removal rate decreased with inlet load. Carbon dioxide concentration profile through the biofilter revealed that the mass ratios of carbon dioxide produced to the toluene and benzene removed were 2.15 g(CO2)/g(toluene) and 1.67 g(CO2)/g(benzene), which furthermore, confirmed the biodegradation performance in biofilter. The observation of biotic community demonstrated that the microbes consisted of bacillus, spore bacillus and fungi, of which the spore bacillus was dominant.


DYNA ◽  
2020 ◽  
Vol 87 (212) ◽  
pp. 9-17
Author(s):  
Claudia Catalina Estrada-Montoya ◽  
Gloria Maria Restrepo Franco ◽  
Narmer Fernando Galeano Vanegas

The small gold mining generates toxic substances discharges, being an environmental problem. The objective was to evaluate the removal of cyanide and heavy metals, in liquid effluents from the gold benefit, by adsorption with activated carbon and hydrogen peroxide. The residues were first treated with carbon to determine the adsorption efficiency with 20, 40, 60 g of carbon / L of solution at times of 4, 8, 12 hours. Then hydrogen peroxide (1.0, 1.5, 2.0 liters of peroxide / Kg CN in solution, was added over 4 hours). The response variables were concentrations of cyanide, lead, zinc, iron. The best treatment with carbon was 60 g of carbon / L of solution and 12 hours of contact and for the process with hydrogen peroxide: 2 liters of H2O2 / Kg of CN in solution, during 4 hours. A flow chart and tables for the implementation of the process were designed.


2019 ◽  
Vol 14 (4) ◽  
pp. 897-907 ◽  
Author(s):  
Hosseinali Asgharnia ◽  
Hamidreza Nasehinia ◽  
Roohollah Rostami ◽  
Marziah Rahmani ◽  
Seyed Mahmoud Mehdinia

Abstract Phenol and its derivatives are organic pollutants with dangerous effects, such as poisoning, carcinogenicity, mutagenicity, and teratogenicity in humans and other organisms. In this study, the removal of phenol from aqueous solution by adsorption on silica and activated carbon of rice husk was investigated. In this regard, the effects of initial concentration of phenol, pH, dosage of the adsorbents, and contact time on the adsorption of phenol were investigated. The results showed that the maximum removal of phenol by rice husk silica (RHS) and rice husk activated carbon (RHAC) in the initial concentration of 1 mgL−1 phenol, 2 gL−1 adsorbent mass, 120 min contact time, and pH 5 (RHS) or pH 6 (RHAC) were obtained up to 91% and 97.88%, respectively. A significant correlation was also detected between increasing contact times and phenol removal for both adsorbents (p < 0.01). The adsorption process for both of the adsorbents was also more compatible with the Langmuir isotherm. The results of this study showed that RHS and RHAC can be considered as natural and inexpensive adsorbents for water treatment.


2015 ◽  
Vol 72 (6) ◽  
pp. 983-989 ◽  
Author(s):  
Zheng-ji Yi ◽  
Jun Yao ◽  
Yun-fei Kuang ◽  
Hui-lun Chen ◽  
Fei Wang ◽  
...  

The excessive discharge of Pb(II) into the environment has increasingly aroused great concern. Adsorption is considered as the most effective method for heavy metal removal. Chinese walnut shell activated carbon (CWSAC) was used as an adsorbent for the removal of Pb(II) from aqueous solution. Batch experiments were conducted by varying contact time, temperature, pH, adsorbent dose and initial Pb(II) concentration. Adsorption equilibrium was established within 150 min. Although temperature effect was insignificant, the Pb(II) adsorption was strongly pH dependent and the maximum removal was observed at pH 5.5. The Pb(II) removal efficiency increased with increasing CWSAC dosage up to 2.0 g/L and reached a maximum of 94.12%. Langmuir and Freundlich adsorption isotherms were employed to fit the adsorption data. The results suggested that the equilibrium data could be well described by the Langmuir isotherm model, with a maximum adsorption capacity of 81.96 mg/g. Adsorption kinetics data were fitted by pseudo-first- and pseudo-second-order models. The result indicated that the pseudo-first-order model best describes the adsorption kinetic data. In summary, CWSAC could be a promising material for the removal of Pb(II) from wastewater.


BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 6781-6790
Author(s):  
Moammar Elbidi ◽  
Agab Hewas ◽  
Rajab Asar ◽  
Mohamad Amran Mohd Salleh

Removal of phenol from wastewater using local biochar (BC) was investigated, while using activated carbon (AC) as a reference material. The main parameters affecting the sorption process were initial concentration, contact time, pH, and temperature. Statistical analysis of the results showed that the maximum removal percent when using AC and BC were 95% and 55%, respectively. Experimental data showed that the removal of phenol has fast kinetics and reached equilibrium within 5 minutes. The Langmuir and Freundlich isotherm models were applied to fit the adsorption experimental data. Pseudo-first order and pseudo-second order kinetic models were employed.


2018 ◽  
Vol 5 (2) ◽  
pp. 91-99
Author(s):  
Marzieh Bagheri ◽  
Mohammad Nasiri ◽  
Bahareh Bahrami

Nowadays, due to increasing usage of dye in various industries and its destructive effects on health and environment, it is necessary to remove dyes from industrial wastes. Although few studies can be found on using pine cone for removal of different dyes, it has not been used yet to remove Reactive Blue 203 (RB203) dye. The purpose of this study is to investigate RB203 dye adsorption using activated carbon produced from pine cone. Optimal values of influencing factors for RB203 dye removal were obtained. The results showed that the maximum removal was occurred at a pH of 2, temperature of 30˚C, dye concentration of 30 mg/L, adsorbent dosage of 100 mg/L, and contact time of 15 min. The maximum removal percentage was 98.48%. In order to study the synthesized activated carbon, some characterization methods including scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR) spectroscopy and Brunauer-Emmett-Teller (BET) have been used. Investigation of adsorption isotherm models revealed that adsorption of RB203dye can be described through D-R and Temkin isotherm models. Additionally, RB203 dye removal follows the pseudo-firstorder kinetic equation.


2013 ◽  
Vol 48 (2) ◽  
pp. 121-132 ◽  
Author(s):  
S. Piel ◽  
S. Blondeau ◽  
J. Pérot ◽  
E. Baurès ◽  
O. Thomas

The adsorption of some major pharmaceutical products (sulfamethoxazole, caffeine, iopromide and carbamazepine) in water was evaluated using four types of activated carbon, three powdered activated carbon (PAC) and one fluidized, coagulated and flocculated activated carbon (FAC) extracted from a Carboplus®P pilot. These substances were the most frequently quantified (in 50% of samples at least) in surface waters of the Vilaine's basin (Brittany, France) during three sampling campaigns. Jar test experiments were carried out in order to assess the removal efficiency of the four activated carbons. Carbamazepine and caffeine were well removed with PAC with a maximum removal rate of 80% whereas it was more difficult for sulfamethoxazole and iopromide with a maximum of 39%. For each molecule, removal rates are clearly dependent on PAC nature. The overall results with FAC are clearly distinguishable from PAC tests with gains of performance on all target molecules (from 80 to >95%).


2015 ◽  
Vol 72 (12) ◽  
pp. 2229-2235 ◽  
Author(s):  
Xiaohong Liu ◽  
Fang Wang ◽  
Song Bai

An original activated carbon prepared from walnut peel, which was activated by zinc chloride, was modified with ammonium hydroxide or sodium hydroxide in order to contrast the adsorption property of the three different activated carbons. The experiment used a static adsorption test for p-nitrophenol. The effects of parameters such as initial concentration, contact time and pH value on amount adsorbed and removal are discussed in depth. The thermodynamic data of adsorption were analyzed by Freundlich and Langmuir models. The kinetic data of adsorption were measured by the pseudo-first-order kinetics and the pseudo-second-order kinetics models. The results indicated that the alkalized carbon samples derived from walnut peel had a better performance than the original activated carbon treated with zinc chloride. It was found that adsorption equilibrium time was 6 h. The maximum removal rate of activated carbon treated with zinc chloride for p-nitrophenol was 87.3% at pH 3,whereas the maximum removal rate of the two modified activated carbon materials was found to be 90.8% (alkalized with ammonium hydroxide) and 92.0% (alkalized with sodium hydroxide) at the same pH. The adsorption data of the zinc chloride activated carbon were fitted to the Langmuir isotherm model. The two alkalized activated carbon samples were fitted well to the Freundlich model. The pseudo-second-order dynamics equation provided better explanation of the adsorption dynamics data of the three activated carbons than the pseudo-first-order dynamics equation.


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