scholarly journals Magnetic-Based Coreshell Nanoparticles as Potential Adsorbents for the Removal of Cu2+ Under Ultraviolet (UV) Light

2021 ◽  
Vol 2080 (1) ◽  
pp. 012032
Author(s):  
Hazreen Nadihah Husni ◽  
Norsuria Mahmed ◽  
Yanling Ge ◽  
Mohd Natashah Norizan ◽  
Dewi Suriyani Che Halin ◽  
...  
Keyword(s):  
Active Sites ◽  
Adsorption Process ◽  
Copper Ions ◽  
Silver Chloride ◽  
Uv Light ◽  
Copper Ion ◽  
Magnetic Core ◽  
Lower Percentage ◽  
Wet Chemistry ◽  
Maximum Removal

Abstract The magnetite (Fe3O4) and maghemite (γFe2O3) nanopartides, magnetite-silica-silver chloride (Fe3O4-SiO2-AgCl) and maghemite-silica-silver chloride (γFe2O3-SiO2-AgCl) coreshell structures have successfully been synthesized by using a simple wet chemistry method. The efficiency of these particles as the adsorbents for the removal of copper ion, Cu2+ in aqueous solution under UV light was investigated. Two different parameters were studied, namely the adsorbents contact time (60, 120, 180, 240 and 300s) and the solution-stirring rate (100, 200 and 300 rpm). From the results, the removal percentage of the copper ions from the solution were above 90% after 5 hours of adsorption process at 300 rpm by using Fe3O4 (94%) and γFe2O3 (92%) nanoparticles. The maximum removal of copper ions was nearly 100% when yFe2O3-SiO2-AgCl & Fe3O4-SiO2-AgCl coreshell particles were used. The samples that were prepared without magnetic core such as AgCl-SiO2, AgCl and SiO2 particles, showed lower percentage of the copper ions removal (78%, 60% and 20%, respectively). This situation shows that the magnetic nanoparticles plays and important role during the adsorption process due to their large active sites for the adsorption to occur.

Active Site Structure in Zeolite-Supported Lean NOx Catalysts

1997 ◽  
Vol 492 ◽  
Author(s):  
Richard J. Blint
Keyword(s):  
Homogeneous Catalysis ◽  
Active Site ◽  
Active Sites ◽  
Catalytic Mechanism ◽  
Copper Ions ◽  
Hydration Shell ◽  
Copper Ion ◽  
Acid Sites ◽  
Reduction Of No ◽  
Dynamics Simulations

AbstractCopper ions exchanged into the zeolite, ZSM-5, are known to catalyze the reduction of NO to N2 in the oxidizing environment of lean automotive exhaust, but do require trace hydrocarbons. The interface of this catalyst provides a locally reducing environment even when the surrounding exhaust has molecular oxygen concentrations as high as 10%. The mechanism of this reduction is still unclear; however, structure calculations of the active sites and dynamics simulations of species diffusion within the zeolite pores provide insight into the mechanism of reduction. One active site is proposed to be Cu++ ionically bound to a bridge oxygen in a nonsymmetric site within a zeolitic pore. Another proposed site has the copper ion centrally (symmetrically) bound within a six member zeolitic ring. Evidence suggests that the copper ions cycle between Cu++ and Cu+ during the reduction of NO to N2. The nonsymmetric copper ions are shown here to be hydrated ions attached to the Brønsted acid sites in the zeolite. The calculations here show a four member, first hydration shell for Cu++ and a first shell of 2–3 oxygens for the Cu+ ion. An examination of the pore size in ZSM-5 indicates sufficient room for a first and second hydration shell for most of the possible acid sites. The conclusion that the copper ions are typically hydrated suggests that the catalytic mechanism may have much in common with homogeneous catalysis which is sometimes termed heterogenized homogeneous catalysis.

scholarly journals Performance of Silica Adsorbent Material for Removing Copper Ions from Produced Water

2020 ◽  
Vol 2 (1) ◽  
pp. 8-11
Author(s):  
Z Karm ◽  
R. Sehud ◽  
A. Dhahir
Keyword(s):  
Removal Efficiency ◽  
Contact Time ◽  
Adsorption Process ◽  
Produced Water ◽  
Copper Ions ◽  
Adsorbent Dosage ◽  
Silica Adsorbent ◽  
Efficiency Conditions ◽  
Maximum Removal

In this study investigation , the utilization silica for removal of copper ions from produced water by the adsorption process. Examination was carried out by studying several parameters like pH solution, adsorbent dosage and contact time. Experiments of adsorption were done at 25 ˚C . Copper ions adsorption was very influenced by the pH of solution . The maximum removal efficiency reached (99.99) when the pH was 7. The optimum removal efficiency conditions for Cu2+ using silica are pH 7, contact time 60 min, and dose of silica adsorbent 0.4 mg.

scholarly journals Study on antibacterial and copper ion removal of chitosan fiber/acetate fiber and yarn for water purification

2021 ◽  
Vol 16 ◽  
pp. 155892502110613
Author(s):  
Yating Zhang ◽  
Shujie Zhang ◽  
Lisong Fu ◽  
Mengke Jing
Keyword(s):  
Cellulose Acetate ◽  
Adsorption Process ◽  
Copper Ions ◽  
Copper Ion ◽  
Filtration Efficiency ◽  
Mixing Ratio ◽  
Obvious Effect ◽  
Mixing Ratios ◽  
Adsorption Performance ◽  
Chitosan Fiber

Use chitosan (CS) fiber and cellulose acetate (CA) fiber with different mixing ratios as raw materials, the kinetic and thermodynamic characteristics of the adsorption process of chitosan fiber/cellulose acetate fiber (CS/CA) ratio of 90:10 are explored, and the adsorption process conforms to the quasi-second-order kinetic equation. It can be fitted by Langmuir isotherm. The adsorption process is a spontaneous thermal reaction with both physical adsorption and chemical adsorption. The best adsorption time is 30 min, the time to reach adsorption equilibrium is 180 min, and the best adsorption pH is 5, the most suitable temperature is 35°C, and rising the temperature is conducive to the fibers adsorption. The materials before and after the CS/CA blended yarn adsorbed copper ions were characterized by XRD, DSC, FT-IR, and the adsorption mechanism was analyzed. In the orthogonal experiment, the copper ions concentration has the most obvious effect on the adsorption capacity, and the temperature has the most obvious effect on the adsorption efficiency. The optimal adsorption combination is that the mixing ratio of chitosan fiber/cellulose acetate (CS/CA) is 80:20, the pH is 5, the temperature is 35°C, and the copper ion concentration is 100 mg L−1. Comparing the adsorption performance of fibers with different mixing ratios, the adsorption performance of CS/CA ratio of 90:10 is the best. The filtration efficiency of the filter material, made of fibers with different mixing ratios, to copper ions is tested, and the filtration performance with a mixing ratio of 90:10 is the best, and the filtration efficiency is 64.33%.

scholarly journals Anchoring zinc-doped carbon dots on a paper-based chip for highly sensitive fluorescence detection of copper ions

The Analyst ◽  
2021 ◽  
Vol 146 (20) ◽  
pp. 6297-6305
Author(s):  
Qinglan Miao ◽  
Ji Qi ◽  
Yuanyuan Li ◽  
Xinxia Fan ◽  
Dongmei Deng ◽  
...  
Keyword(s):  
Fluorescence Detection ◽  
Carbon Dots ◽  
Active Sites ◽  
Copper Ions ◽  
Fluorescent Detection ◽  
Zn Doping ◽  
Highly Sensitive ◽  
Doped Carbon Dots

A novel paper-based chip that anchored zinc-doped carbon dots was constructed for sensitive and stable fluorescent detection of Cu2+. Zn doping increased the active sites for simplifying the modification of carbon dots.

scholarly journals An Investigation on Design and Characterization of a Highly Selective LED Optical Sensor for Copper Ions in Aqueous Solutions

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1099
Author(s):  
Sheng-Chun Hung ◽  
Chih-Cheng Lu ◽  
Yu-Ting Wu
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Copper Ions ◽  
Incident Light ◽  
Copper Ion ◽  
Intensity Change ◽  
Optical Absorbance ◽  
Sensing System ◽  
Optic Sensor ◽  
Cu Ions

The optical characteristics of copper ion detection, such as the photometric absorbance of specific wavelengths, exhibit significant intensity change upon incident light into the aqueous solutions with different concentrations of metal ions due to the electron transition in the orbit. In this study, we developed a low-cost, small-size and fast-response photoelectric sensing prototype as an optic sensor for copper (Cu) ions detection by utilizing the principle of optical absorption. We quantified the change of optical absorbance from infra-red (IR) light emitting diodes (LEDs) upon different concentrations of copper ions and the transmitted optical signals were transferred to the corresponding output voltage through a phototransistor and circuit integrated in the photoelectric sensing system. The optic sensor for copper (Cu) ions demonstrated not only excellent specificity with other metal ions such as cadmium (Cd), nickel (Ni), iron (Fe) and chloride (Cl) ions in the same aqueous solution but also satisfactory linearity and reproducibility. The sensitivity of the preliminary sensing system for copper ions was 29 mV/ppm from 0 to 1000 ppm. In addition, significant ion-selective characteristics and anti-interference capability were also observed in the experiments by the proposed approach.

scholarly journals Eggshell Powder as an Adsorbent for Removal of Fluoride from Aqueous Solution: Equilibrium, Kinetic and Thermodynamic Studies

2012 ◽  
Vol 9 (3) ◽  
pp. 1457-1480 ◽  
Author(s):  
R. Bhaumik ◽  
N. K. Mondal ◽  
B. Das ◽  
P. Roy ◽  
K. C. Pal ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Adsorption Process ◽  
Low Cost ◽  
Fluoride Removal ◽  
Contaminated Water ◽  
Fluoride Adsorption ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Kinetic And Thermodynamic Studies ◽  
Maximum Removal

A new medium, eggshell powder has been developed for fluoride removal from aqueous solution. Fluoride adsorption was studied in a batch system where adsorption was found to be pH dependent with maximum removal efficiency at 6.0. The experimental data was more satisfactorily fitted with Langmuir isotherm model. The kinetics and the factor controlling adsorption process fully accepted by pseudo-second-order model were also discussed. Eawas found to be 45.98 kJmol-1by using Arrhenius equation, indicating chemisorption nature of fluoride onto eggshell powder. Thermodynamic study showed spontaneous nature and feasibility of the adsorption process with negative enthalpy (∆H0) value also supported the exothermic nature. Batch experiments were performed to study the applicability of the adsorbent by using fluoride contaminated water collected from affected areas. These results indicate that eggshell powder can be used as an effective, low-cost adsorbent to remove fluoride from aqueous solution as well as groundwater.

scholarly journals Removal of toxic metals from aqueous solution by biochars derived from long-root Eichhornia crassipes

2018 ◽  
Vol 5 (10) ◽  
pp. 180966 ◽  
Author(s):  
Qiang Li ◽  
Lizhou Tang ◽  
Jiang Hu ◽  
Ming Jiang ◽  
Xiaodong Shi ◽  
...  
Keyword(s):  
Toxic Metals ◽  
Eichhornia Crassipes ◽  
Adsorption Process ◽  
Correlation Coefficients ◽  
Sorption Ability ◽  
Different Temperatures ◽  
Lead Zinc ◽  
Pseudo Second Order ◽  
Cyano Groups ◽  
Maximum Removal

Biochars were produced from long-root Eichhornia crassipes at four temperatures: 200, 300, 400 and 500°C, referred to as LEC200, LEC300, LEC400 and LEC500, respectively. The sorption ability of lead, zinc, copper and cadmium from aqueous solutions by four kinds of biochars was investigated. All the biochars had lower values of CEC and higher values of pH. LEC500 was the best one to bind toxic metals which can be reflected in the results of SEM, BET and elemental analyser. It was also found that alkyl, carboxyl, phosphate and cyano groups in the biochars can play a role in binding metals. In addition, the sorption processes of four metals by the biochars in different metal concentration were all excellently represented by the pseudo-second-order model with all correlation coefficients R 2 > 0.95. And the sorption processes of four metals in different temperatures could be described satisfactorily by the Langmuir isotherms. According to calculated results by the Langmuir equation, the maximum removal capacities of Pb(II), Zn(II), Cu(II) and Cd(II) at 298 K were 39.09 mg g −1 , 45.40 mg g −1 , 48.20 mg g −1 and 44.04 mg g −1 , respectively. The positive value of the Δ H 0 confirmed the adsorption process was endothermic and the negative value of Δ G 0 confirmed the adsorption process was spontaneous. The sorption capacities were compared with several other lignocellulosic materials which implied the potential of long-root Eichhornia crassipes waste as an economic and excellent biosorbent for eliminating metal ions from contaminated waters.

Biomimetic synthesis of needle-like fluorescent calcium phosphate/carbon dot hybrid composites for cell labeling and copper ion detection

2016 ◽  
Vol 45 (18) ◽  
pp. 7665-7671 ◽  
Author(s):  
Shanshan Guo ◽  
Shousi Lu ◽  
Pingxiang Xu ◽  
Yi Ma ◽  
Liang Zhao ◽  
...  
Keyword(s):  
Drinking Water ◽  
Calcium Phosphate ◽  
Copper Ions ◽  
Hybrid Composites ◽  
Copper Ion ◽  
Cell Labeling ◽  
Biomimetic Synthesis ◽  
Selective Detection ◽  
Sodium Carboxymethylcellulose ◽  
Biomimetic Method

We report a biomimetic method to synthesize needle-like calcium phosphate (CaP) using carbon dots (CDs) and sodium carboxymethylcellulose as dual templates. The CaP/CDs were capable of cell labeling and selective detection of copper ions in drinking water.

scholarly journals Experimental studies on equilibrium adsorption isosteres and determination of the thermodynamic quantities of polar media on alumina Al2O3

2017 ◽  
Vol 4 (1) ◽  
pp. 34-45 ◽  
Author(s):  
Albena Yonova
Keyword(s):  
Active Sites ◽  
Adsorption Process ◽  
Surface Acidity ◽  
Experimental Studies ◽  
Isosteric Heat ◽  
Heat Of Adsorption ◽  
Equilibrium Adsorption ◽  
Thermodynamic Quantities ◽  
Isosteric Heat Of Adsorption ◽  
Adsorption Isosteres

Abstract The present work is a revieif of theoretical and experimental study on the adsorption performance of the adsorbent Alumina (Al2O3) used in the adsorption system. An experimental investigation on the equilibrium adsorption isosteres at low pressure (< 1 atm) of working pairs Al2O3/H2O and Al2O3/C2H6O2 is carried out. The isovolume measurement method is adopted in the test setup to directly measure the saturated vapor pressures of working pairs at vapor-liquid equilibrium (dG=0 and dμi=0). Quantity adsorbed is determined from pressure, volume and temperature using gas law. The isosteric heat of adsorption is calculated from the slope of the plot of lnP versus 1/T different amounts of adsorbate onto adsorbent as follows: 0,01 vol% Al2O3/H2O; 0,03 vol% Al2O3/H2O; 0,1 vol% Al2O3/H2O; 0,01 vol% Al2O3/C2H6O2; 0,03 vol% Al2O3/C2H6O2; 0,1 vol% Al2O3/C2H6O2. This study shows that adsorption working pair Al2O3 C2H6O2 has better adsorption performances than those of the A2O3/H2O. Surface acidity! is a most important property! far both adsorption and catalysis and therefore is examined structure of active sites of alumina surface. Thermodynamic parameters such as isosteric heat of adsorption, isosteric enthalpy and entropy of adsorption are critical design variables in estimating the performance and predicting the mechanism of an adsorption process and are also one of the basic requirements for the characterization and optimization of an adsorption process

A REVERSIBLE OPTICAL SENSOR BASED ON CHITOSAN FILM FOR THE SELECTIVE DETECTION OF COPPER IONS

2012 ◽  
Vol 24 (05) ◽  
pp. 453-459 ◽  
Author(s):  
Shenhsiung Lin ◽  
Chia-Chen Chang ◽  
Chii-Wann Lin
Keyword(s):  
Functional Groups ◽  
Inductively Coupled Plasma ◽  
Copper Ions ◽  
Three Dimensional ◽  
Copper Ion ◽  
Chitosan Film ◽  
Detection Limits ◽  
Dimensional Structure ◽  
Optical Detectors ◽  
Inductively Coupled

Heavy metals greatly influence animal physiology, even at small doses. Among these metals, the copper ion is of great concern due to its effects on humans and wide applications in industry. Compared to atomic absorption spectroscopy and inductively coupled plasma-mass spectrometry, which destroy the samples that are analyzed, optical techniques do not decompose the analyte and have become a popular field of recent research. In this paper, we combined a novel optical detector that did not require sample-labeling, called surface plasmon resonance (SPR), with chitosan to detect copper ions by modifying the functional groups of chitosan through pH modification. Compared to other optical detectors, the SPR system was relatively fast and involved fewer experimental confounding factors. The three-dimensional structure of chitosan was used to obtain lower detection limits. Moreover, modification of the chitosan functional groups resulted in efficient regeneration by controlling the pH. A detection limit of 0.1 μM was obtained (linear range: 0.5–10 μM, R2 = 0.976), and the specificity was certified by comparing the copper ion with six other ions. Additionally, we successfully regenerated the SPR chips by modifying the functional groups. In conclusion, the chitosan–SPR system detected copper ions with improved detection limits using a quick and simple regeneration method.

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