scholarly journals The Thermal and Radiation Oxidation of Benzene to Phenol in Aqueous Solutions Containing Metal Ions at Elevated Temperatures. IV. The Effect of Impurities in Benzene

1964 ◽  
Vol 37 (2) ◽  
pp. 244-248 ◽  
Author(s):  
Nobutake Suzuki ◽  
Hiroshi Hotta
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Elevated Temperatures ◽  
Effect Of Impurities ◽  
Oxidation Of Benzene

Chitosan-based Magnetic Composites - Efficient Adsorbents for Removal of Pb(II) and Cu(II) from Aqueous Mono and Bicomponent Solutions

2018 ◽  
Vol 69 (9) ◽  
pp. 2323-2330 ◽  
Author(s):  
Daniela C. Culita ◽  
Claudia Maria Simonescu ◽  
Rodica Elena Patescu ◽  
Nicolae Stanica
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Chemical Properties ◽  
Order Kinetic ◽  
Mass Ratio ◽  
Magnetic Adsorbent ◽  
Magnetic Composites ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Physical And Chemical

A series of three chitosan-based magnetic composites was prepared through a simple coprecipitation method. It was investigated the influence of mass ratio between chitosan and magnetite on the physical and chemical properties of the composites in order to establish the optimum conditions for obtaining a composite with good adsorption capacity for Pb(II) and Cu(II) from mono and bicomponent aqueous solutions. It was found that the microspheres prepared using mass ratio chitosan / magnetite 1.25/1, having a saturation magnetization of 15 emu g--1, are the best to be used as adsorbent for the metal ions. The influence of different parameters such as initial pH values, contact time, initial concentration of metal ions, on the adsorption of Pb(II) and Cu(II) onto the chitosan-based magnetic adsorbent was investigated in details. The adsorption process fits the pseudo-second-order kinetic model in both mono and bicomponent systems, and the maximum adsorption capacities calculated on the basis of the Langmuir model were 79.4 mg g--1 for Pb(II) and 48.5 mg g--1 for Cu(II) in monocomponent systems, while in bicomponent systems were 88.3 and 49.5 mg g--1, respectively. The results revealed that the as prepared chitosan-based magnetic adsorbent can be an effective and promising adsorbent for Pb(II) and Cu(II) from mono and bicomponent aqueous solutions.

Comparison of the fixation of several metal ions onto a low-cost biopolymer

2002 ◽  
Vol 2 (5-6) ◽  
pp. 217-224 ◽  
Author(s):  
Z. Reddad ◽  
C. Gérente ◽  
Y. Andrès ◽  
P. Le Cloirec
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Low Cost ◽  
Operating Conditions ◽  
Order Kinetic ◽  
Adsorption Mechanisms ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Beet Pulp ◽  
Removal Of Metal Ions

In the present work, sugar beet pulp, a common waste from the sugar refining industry, was studied in the removal of metal ions from aqueous solutions. The ability of this cheap biopolymer to sorb several metals namely Pb2+, Cu2+, Zn2+, Cd2+ and Ni2+ in aqueous solutions was investigated. The metal fixation capacities of the sorbent were determined according to operating conditions and the fixation mechanisms were identified. The biopolymer has shown high elimination rates and interesting metal fixation capacities. A pseudo-second-order kinetic model was tested to investigate the adsorption mechanisms. The kinetic parameters of the model were calculated and discussed. For 8 × 10-4 M initial metal concentration, the initial sorption rates (v0) ranged from 0.063 mmol.g-1.min-1 for Pb2+ to 0.275 mmol.g-1.min-1 for Ni2+ ions, with the order: Ni2+ > Cd2+ > Zn2+ > Cu2+ > Pb2+. The equilibrium data fitted well with the Langmuir model and showed the following affinity order of the material: Pb2+ > Cu2+ > Zn2+ > Cd2+ > Ni2+. Then, the kinetic and equilibrium parameters calculated qm and v0 were tentatively correlated to the properties of the metals. Finally, equilibrium experiments in multimetallic systems were performed to study the competition of the fixation of Pb2+, Zn2+ and Ni2+ cations. In all cases, the metal fixation onto the biopolymer was found to be favourable in multicomponent systems. Based on these results, it is demonstrated that this biosorbent represents a low-cost solution for the treatment of metal-polluted wastewaters.

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.

Sign in / Sign up

Export Citation Format

Share Document