Research on Pesticide Adsorption Mechanism of Corn Stalk Biochar Based on Koh Thermal Activation

2020 ◽  
Vol 29 (5) ◽  
Author(s):  
Wang Minghua ◽  
Cai Honglan ◽  
Qiao Qingan ◽  
Zhang Jiang
Keyword(s):  
Thermal Activation ◽  
Adsorption Mechanism ◽  
Corn Stalk ◽  
Pesticide Adsorption

scholarly journals Experimental Investigations on Adsorption of Reactive Toxic Dyes Using Hedyotis umbellate Activated Carbon

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Jayachandran Sheeja ◽  
Krishnan Sampath ◽  
Ramasamy Kesavasamy
Keyword(s):  
Activated Carbon ◽  
Thermal Activation ◽  
Adsorption Mechanism ◽  
Entropy Change ◽  
Experimental Investigations ◽  
Control Parameters ◽  
Gibbs Free Energy Change ◽  
Multilayer Adsorption ◽  
Monolayer Adsorption ◽  
Adsorption Data

Hedyotis umbellate activated carbon (HUAC) was prepared by chemical and thermal activation. The adsorption behavior of Hedyotis umbellate activated carbon in aqueous basic green 4 (BG4) and acid fuchsin (AF) was investigated and characterized by UV-vis, FTIR, and FESEM. The possible mechanism of the adsorption of BG4 and AF dyes on the HUAC surface was framed. The influence of various adsorption control parameters like the initial dye concentration, pH, adsorbent dose, contact time, and temperature was studied. The data confirmed excellent BG4 removal of 97.94% at pH 10 and AF removal of 76.7% at pH 4. The experimental data were fitted using Langmuir, Freundlich, and Temkin isotherms to examine the adsorption mechanism. The adsorption data revealed monolayer adsorption of BG4 with the maximum capacity of 102.38 mg/g and multilayer adsorption of AF with the capacity of 139.33 mg/g. The kinetic data for different initial dye concentrations were computed using pseudofirst order, pseudosecond order, and intraparticle diffusion models. Thermodynamic parameters like Gibbs free energy change ∆ G 0 , enthalpy change ∆ H 0 , and entropy change ∆ S 0 were evaluated. From the values obtained, the negative values of ∆ G 0 and ∆ H 0 indicate that the adsorption of BG4 and AF by HUAC is spontaneous and exothermic.

X- ray diffraction and dielectric properties of PbSe thin films

2019 ◽  
Vol 15 (34) ◽  
pp. 1-14
Author(s):  
Bushra A. Hasan
Keyword(s):  
Thin Films ◽  
Thermal Activation ◽  
Thermal Evaporation ◽  
Thermal Activation Energy ◽  
Dielectric Constants ◽  
Conductivity Measurements ◽  
X Ray Diffraction ◽  
Thermal Evaporation Method ◽  
X Ray ◽  
Glass Substrates

Lead selenide PbSe thin films of different thicknesses (300, 500, and 700 nm) were deposited under vacuum using thermal evaporation method on glass substrates. X-ray diffraction measurements showed that increasing of thickness lead to well crystallize the prepared samples, such that the crystallite size increases while the dislocation density decreases with thickness increasing. A.C conductivity, dielectric constants, and loss tangent are studied as function to thickness, frequency (10kHz-10MHz) and temperatures (293K-493K). The conductivity measurements confirm confirmed that hopping is the mechanism responsible for the conduction process. Increasing of thickness decreases the thermal activation energy estimated from Arhinus equation is found to decrease with thickness increasing. The increase of thickness lead to reduce the polarizability α while the increasing of temperature lead to increase α.

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