Rapid removal of caffeine in aqueous solutions by peroxymonosulfate oxidant activated with cobalt ion

2015 ◽  
Vol 72 (3) ◽  
pp. 478-483 ◽  
Author(s):  
Yunleiyu Guo ◽  
Tingting Shen ◽  
Chen Wang ◽  
Jing Sun ◽  
Xikui Wang

The removal of caffeine (CAF) in aqueous solution by peroxymonosulfate oxidant activated with cobalt ion was investigated under a variety of operating conditions. The effects of various operating parameters, such as oxone and Co2+ concentrations, pH value, and the coexistence of dissolved organic matter and inorganic anions on the removal of CAF have been investigated. The removal efficiency increased with the increase in the concentrations of oxone and Co2+ ion added. The additions of chloride, bicarbonate, and sodium humate have negative effects on the removal of CAF. Near-neutral condition (5.0 < pH < 7.0) is favorable for the removal of CAF. Based on our experiments, 100% degradation of 50 mg/L CAF can be achieved within 4 minutes under the conditions of 1.00 mM oxone and 0.10 mM Co2+ ion at pH 5.0–7.0.

2002 ◽  
Vol 20 (4) ◽  
pp. 393-416 ◽  
Author(s):  
Fawzi Banat ◽  
Sameer Al-Asheh ◽  
Dheaya‘ Al-Rousan

This study examined and compared the ability of chicken feathers, human hair and animal horns, as keratin-composed biosorbents, for the removal of Zn2+ and Cu2+ ions from single metal ion aqueous solutions under different operating conditions. The three biosorbents investigated in this study were all capable of adsorbing Zn2+ and Cu2+ ions from aqueous solutions. The biosorbent showing the highest uptake of Zn2+ and Cu2+ ions was animal horns. Chicken feathers showed a higher Cu2+ ion uptake and a lower Zn2+ ion compared to human hair. Increasing the initial concentration of Zn2+ or Cu2+ ions, or increasing the initial pH value, increased the metal ion uptake. Such uptake decreased when the temperature was raised from 25°C to 50°C for all adsorbent/metal ion combinations except for Zn2+ ion/human hair where the uptake increased with temperature. It was demonstrated that the addition of NaCl salt to the metal ion solution depressed the metal ion uptake. The Freundlich isotherm model was found to be applicable to the adsorption data for Cu2+ and Zn2+ ions.


2013 ◽  
Vol 68 (9) ◽  
pp. 2074-2081 ◽  
Author(s):  
Qian Liu ◽  
Ruihua Huang ◽  
Bingchao Yang ◽  
Yanping Liu

In this work, enhanced chitosan/bentonite composite was prepared by treating chitosan/bentonite composite with concentrated hydrochloric acid (HCl). The adsorption of fluoride ions from aqueous solution onto the enhanced chitosan/bentonite composite was investigated. Adsorption studies were performed in a batch system, and the effects of various parameters, such as the pH value of the solution, adsorbent dosage and initial fluoride concentration, were evaluated. The optimum operating conditions for fluoride removal by the enhanced chitosan/bentonite composite were pH = 7 or so, and adsorbent dosage =1.2 g. Increasing initial fluoride concentration reduced the adsorption of fluoride onto the enhanced chitosan/bentonite composite. Furthermore, the presence of other co-anions weakened the adsorption of fluoride onto this adsorbent. The equilibrium adsorption isotherms were well described by both the Freundlich and Langmuir models. The maximum monolayer adsorption capacity was 2.95 mg/g at 293 K.


2015 ◽  
Vol 5 (4) ◽  
pp. 610-618 ◽  
Author(s):  
Qian Liu ◽  
Lujie Zhang ◽  
Pan Hu ◽  
Ruihua Huang

In this work, activated carbon (AC) coated by chitosan was synthesized and characterized by Fourier transform infrared spectrophotometer and scanning electron microscope (SEM) techniques. The removal of aniline from aqueous solutions by AC coated by chitosan was investigated. The factors affecting the adsorption of aniline onto AC coated by chitosan, including the ratio of AC to chitosan, adsorbent dosage, pH value of solution, initial aniline concentration, and contact time were evaluated. These results showed that the optimum operating conditions were: the ratio of AC to chitosan = 0.5, adsorbent dosage = 0.2 g, and the adsorption of aniline from aqueous solutions had better removal in the concentration range of 20–50 mg/L. This adsorbent allowed high removal toward aniline in a wide range of pH. The equilibrium time was 100 minutes. The Freundlich model exhibited better correlation of the equilibrium adsorption data. The pseudo-second-order kinetic equation could better describe the kinetic behavior of aniline adsorption.


10.14311/888 ◽  
2006 ◽  
Vol 46 (6) ◽  
Author(s):  
L. Kalvoda ◽  
R. Klepáček

Extraction of alkali ions from aqueous solutions of chlorides and hydroxides into a lipophilic liquid membrane composed of tetraethyl p-tert-butylcalix[4]arene tetraacetate (TBT) solution in hexane was investigated by means of measurements of changes in the electrolytic conductivity and pH-value of the aqueous solution. Hydrolysis of the TBT ionophore resulting in the release of the ethyl groups was proposed as the main reaction process, leading to disturbance of the known preference of TBT for sodium ions. 


2012 ◽  
Vol 518-523 ◽  
pp. 436-439 ◽  
Author(s):  
Hui Liu ◽  
Le Guan

Photolysis is expected to be a major degradation process for pollutants in surface water. This paper studied the photodegradation of metribuzin, a widely used herbicide, in aqueous solution under simulated solar light irradiation. Photolysis of metribuzin was enhanced by the higher light intensity, and the major products were deaminometribuzin and nitrite ions. Metribuzin degradation was inhibited in the absence of oxygen and at higher pH value. In addition, iron in water promoted the degradation of metribuzin, while dissolved organic matter lowered the degradation rate. This investigation is helpful for better understanding the transformation and the potential ecological risk of metribuzin in natural water.


Weed Science ◽  
1983 ◽  
Vol 31 (4) ◽  
pp. 528-532 ◽  
Author(s):  
Patrick J. Shea ◽  
Jerome B. Weber

Adsorption and desorption characteristics of fluridone (1-methyl-3-phenyl-5-[3-txifluoromethyl)phenyl]-4-(1H)-pyridinone} on prepared clays and organic matter were studied in unbuffered and buffered aqueous solutions. In unbuffered aqueous solution the adsorption of fluridone decreased in the order: H-saturated organic matter (H-OM) > Ca-saturated montmorillonite (Ca-mont) > Ca-saturated organic matter (Ca-OM) > kaolinite. Based on the chemistry of fluridone, the nature of the adsorbent, and previously reported studies, the major adsorption mechanisms appear to be pH-dependent adsorption of protonated fluridone and direct protonation of the herbicide at acidic surfaces, supplemented by physical adsorption forces such as van der Waals attractions and charge transfer bonds. The adsorption of fluridone on Norfolk sand (Typic Paleudult; fine-loamy, siliceous, thermic), unmodified (CK), or amended with montmorillonite (HC) or organic matter (HM) at pH 4.0, 5.2, and 7.0 was also studied. Over all adsorption was greatest on HC soil, least on CK soil, and intermediate on the HM soil. In each system adsorption was inversely related to pH. These results were interpreted by comparison with adsorption observed on prepared clay minerals and organic matter.


2009 ◽  
Vol 166 (2-3) ◽  
pp. 925-930 ◽  
Author(s):  
A. Ahmadpour ◽  
M. Tahmasbi ◽  
T. Rohani Bastami ◽  
J. Amel Besharati

2020 ◽  
Vol 58 (5A) ◽  
pp. 170
Author(s):  
Bạch Long Giang ◽  
Lam Van Tan ◽  
To-Uyen T. Dao ◽  
Hong-Tham T Nguyen ◽  
Trinh Duy Nguyen

Recent interest in wastewater treatment has shifted to the use of agricultural waste to treat antibiotics in aqueous solutions due the economic efficiency the technique brings. This study focuses on the synthesis, properties and study of the kinetic mechanism of activated carbon and its potential application to remove antibiotics from aqueous solutions. Activated carbon is synthesized from sugarcane bagasse by activated method with active substance of ZnCl2. With a specific surface area of about 980.84 m2/g and high porosity, the product could absorb a large amount of ciprofloxacin (CIP) antibiotics. The properties of materials are characterized by relevant analytical techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET). The behavior of CIP adsorption was studied under the effect of adsorption dose, initial CIP concentration and pH value. The adsorption and isothermal mechanisms are also studied. The results show that the adsorption adhered to the second kinetic model and the experimental data was found to be reasonably fitted to the Langmuir isotherm. Therefore, activated carbon manufactured from sugarcane bagasse could be used as a potential adsorbent to effectively remove antibiotics from aqueous solution.


TAPPI Journal ◽  
2014 ◽  
Vol 13 (9) ◽  
pp. 51-60
Author(s):  
DENNIS VOSS ◽  
HANS-JOACHIM PUTZ ◽  
SAMUEL SCHABEL

The need for deinking mills to reduce their fresh water consumption has resulted in higher loads of various contaminants in the process water. Lower recovered paper quality also leads to higher contamination levels in the mills. This higher load has an influence on achievable target brightness. The objective of the work was to determine and explain the main reasons for relatively poor deinked pulp quality or poor deinking potential based on the influence of recovered paper composition and process water quality. The process water parameters significantly affect the deinking potential of recovered paper. The test results showed the negative effects of increased water hardness. For standard recovered paper mixtures, flotation selectivity is higher with increasing flotation pH-value. Good results were realized for standard recovered paper with low hardness, low surface tension, and high pH-value. The results for recovered paper containing flexo newsprint could be slightly improved with low hardness, low surface tension, and low pH-value. The results of the test program using design of experiments showed interacting effects of pH-value and surface tension on luminosity and flotation selectivity.


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