Photocatalytic removal of cyanide with illuminated TiO2

2011 ◽  
Vol 64 (7) ◽  
pp. 1383-1387 ◽  
Author(s):  
M. Shirzad Siboni ◽  
M. R. Samarghandi ◽  
J.-K. Yang ◽  
S.-M. Lee
Keyword(s):  
Aqueous Solutions ◽  
Langmuir Isotherm ◽  
Industrial Wastewater ◽  
Photocatalytic Oxidation ◽  
Maximum Adsorption Capacity ◽  
Photocatalytic Reaction ◽  
Solution Ph ◽  
Cyanide Concentration ◽  
Photocatalytic Removal ◽  
Oxidation Efficiency

Effects of TiO2 dosage, pH and initial cyanide concentration on the removal efficiency of cyanide from aqueous solutions with illuminated TiO2 have been investigated. Adsorption and oxidation were recognized as significant processes for the elimination of cyanide. From the Langmuir isotherm, the maximum adsorption capacity was determined as 17.24 mg/g at pH 7. Adsorbed amount of cyanide slightly increased as the TiO2 dosage increased. However, as no significant increase was observed above 1 g/L TiO2, an optimum TiO2 dosage was determined as 1 g/L. Photocatalytic oxidation efficiency of cyanide was greatly affected by the solution pH. It increased as the solution pH decreased. The photocatalytic oxidation efficiency after 120 min was 80.4% at pH 3 while it was only 20.4% at pH 11. Photocatalytic oxidation of cyanide was well described by the second-order kinetics. Photocatalytic reaction with illuminated TiO2 can be effectively applied to treat industrial wastewater contaminated with cyanide.

scholarly journals Fabrication of Carboxymethylcellulose/Metal-Organic Framework Beads for Removal of Pb(II) from Aqueous Solution

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 942 ◽  
Author(s):  
Huo-Xi Jin ◽  
Hong Xu ◽  
Nan Wang ◽  
Li-Ye Yang ◽  
Yang-Guang Wang ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Photoelectron Spectroscopy ◽  
Langmuir Isotherm ◽  
Adsorption Equilibrium ◽  
Isotherm Model ◽  
Maximum Adsorption Capacity ◽  
X Ray ◽  
Metal Organic ◽  
Langmuir Isotherm Model

The ability to remove toxic heavy metals, such as Pb(II), from the environment is an important objective from both human-health and ecological perspectives. Herein, we describe the fabrication of a novel carboxymethylcellulose-coated metal organic material (MOF-5–CMC) adsorbent that removed lead ions from aqueous solutions. The adsorption material was characterized by Fourier-transform infrared spectroscopy, X-ray diffractometry, scanning electron microscopy, and X-ray photoelectron spectroscopy. We studied the functions of the contact time, pH, the original concentration of the Pb(II) solution, and adsorption temperature on adsorption capacity. MOF-5–CMC beads exhibit good adsorption performance; the maximum adsorption capacity obtained from the Langmuir isotherm-model is 322.58 mg/g, and the adsorption equilibrium was reached in 120 min at a concentration of 300 mg/L. The adsorption kinetics is well described by pseudo-second-order kinetics, and the adsorption equilibrium data are well fitted to the Langmuir isotherm model (R2 = 0.988). Thermodynamics experiments indicate that the adsorption process is both spontaneous and endothermic. In addition, the adsorbent is reusable. We conclude that MOF-5–CMC is a good adsorbent that can be used to remove Pb(II) from aqueous solutions.

scholarly journals The Removal of Uranium and Thorium from Their Aqueous Solutions by 8-Hydroxyquinoline Immobilized Bentonite

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 626 ◽  
Author(s):  
Salah ◽  
Gaber ◽  
Kandil
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Langmuir Isotherm ◽  
Freundlich Isotherm ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
Solution Ph ◽  
X Ray ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The sorption of uranium and thorium from their aqueous solutions by using 8-hydroxyquinoline modified Na-bentonite (HQ-bentonite) was investigated by the batch technique. Na-bentonite and HQ-bentonite were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier Transform Infrared (FTIR) spectroscopy. Factors that influence the sorption of uranium and thorium onto HQ-bentonite such as solution pH, contact time, initial metal ions concentration, HQ-bentonite mass, and temperature were tested. Sorption experiments were expressed by Freundlich and Langmuir isotherms and the sorption results demonstrated that the sorption of uranium and thorium onto HQ-bentonite correlated better with the Langmuir isotherm than the Freundlich isotherm. Kinetics studies showed that the sorption followed the pseudo-second-order kinetic model. Thermodynamic parameters such as ΔH°, ΔS°, and ΔG° indicated that the sorption of uranium and thorium onto HQ-bentonite was endothermic, feasible, spontaneous, and physical in nature. The maximum adsorption capacities of HQ-bentonite were calculated from the Langmuir isotherm at 303 K and were found to be 63.90 and 65.44 for U(VI) and Th(IV) metal ions, respectively.

scholarly journals Adsorption isotherm and thermodynamic studies of As(III) removal from aqueous solutions using used cigarette filter ash

2019 ◽  
Vol 9 (8) ◽  
Author(s):  
Pezhman Zein Al-Salehin ◽  
Farid Moeinpour ◽  
Fatemeh S. Mohseni-Shahri
Keyword(s):  
Aqueous Solutions ◽  
Langmuir Isotherm ◽  
Adsorption Equilibrium ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Cigarette Filter ◽  
Electron Microscopy Analysis ◽  
Equilibrium Data ◽  
Thermodynamic Variables ◽  
Adsorption Equilibrium Data

Abstract In the present paper, used cigarette filter ash was prepared and used as an active adsorbent to remove As(III) ions from aqueous solutions. The prepared adsorbent structure was identified by scanning electron microscopy analysis, Brunauer–Emmett–Teller method and energy-dispersive X-ray spectroscopy analysis. The influence of contact time, pH, adsorbent dose and initial concentration of As(III) on the removal of As(III) was assessed. Several isotherm models were checked to illustrate the adsorption equilibrium. The adsorption equilibrium data adapted well with the Langmuir isotherm model. The maximum adsorption capacity of 33.33 mg/g was acquired from the Langmuir isotherm. The calculated thermodynamic variables verified that the adsorption process is spontaneous and endothermic.

Synthesis of NH2-Functionalized Nano-Fe3O4 Magnetic Polymer Adsorbent and its Application for the Removal of Cr (VI) from Industrial Wastewater

2009 ◽  
Vol 79-82 ◽  
pp. 1883-1886 ◽  
Author(s):  
Yong Gang Zhao ◽  
Hao Yu Shen ◽  
Mei Qin Hu ◽  
Feng Wei ◽  
Yun Jie Luo ◽  
...  
Keyword(s):  
Langmuir Isotherm ◽  
Industrial Wastewater ◽  
Ph Value ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Adsorption Efficiency ◽  
Mechanism Study ◽  
Study Results ◽  
Isotherm Adsorption ◽  
Effects Of Ph

In this study, a novel NH2-functionalized nano-sized magnetic polymer (TEPA-NMP) adsorbent coupling with tetraethylenepentamine (TEPA) had been prepared. Its application for the removal of Cr(VI) from industrial wastewater was investigated. Batch adsorption studies were carried out to evaluate the effects of pH value, initial concentration, adsorption isotherm, adsorption kinetics, and desorption characters etc. The adsorption of Cr(VI) reached equilibrium rapidly within 30 mins. The adsorption efficiency of the TEPA-NMP on Cr(VI) was dependent on pH value and the initial Cr(VI) concentration. The adsorption efficiency of Cr(VI) decreased with the increasing of the initial Cr(VI) concentration and pH value. The adsorption data were well fitted with the Langmuir isotherm. The maximum adsorption capacity calculated from the Langmuir isotherm was 370.4 mg/g at temperature of 35 °C and pH of 2.0. Regeneration studies indicated that the adsorbent could be reused for 8 times with only 3.4 % lost of adsorption efficiency. The adsorption mechanism study results suggested that the adsorption of Cr(VI) could be related with electrostatic attraction, ion exchange and coordination interactions.

scholarly journals Core-Shell Structured Magnetic Carboxymethyl Cellulose-Based Hydrogel Nanosorbents for Effective Adsorption of Methylene Blue from Aqueous Solution

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3054
Author(s):  
Yiming Zhou ◽  
Te Li ◽  
Juanli Shen ◽  
Yu Meng ◽  
Shuhua Tong ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Carboxymethyl Cellulose ◽  
Chemical Properties ◽  
Polymer Nanocomposite ◽  
Core Shell ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Solution Ph

This article reports effective removal of methylene blue (MB) dyes from aqueous solutions using a novel magnetic polymer nanocomposite. The core-shell structured nanosorbents was fabricated via coating Fe3O4 nanoparticles with a layer of hydrogel material, that synthesized by carboxymethyl cellulose cross-linked with poly(acrylic acid-co-acrylamide). Some physico-chemical properties of the nanosorbents were characterized by various testing methods. The nanosorbent could be easily separated from aqueous solutions by an external magnetic field and the mass fraction of outer hydrogel shell was 20.3 wt%. The adsorption performance was investigated as the effects of solution pH, adsorbent content, initial dye concentration, and contact time. The maximum adsorption capacity was obtained at neutral pH of 7 with a sorbent dose of 1.5 g L−1. The experimental data of MB adsorption were fit to Langmuir isotherm model and Pseudo-second-order kinetic model with maximum adsorption of 34.3 mg g−1. XPS technique was applied to study the mechanism of adsorption, electrostatic attraction and physically adsorption may control the adsorption behavior of the composite nanosorbents. In addition, a good reusability of 83.5% MB recovering with adsorption capacity decreasing by 16.5% over five cycles of sorption/desorption was observed.

MgO Functionalized Magnetic Activated Carbon Material for Efficient Removal of Malachite Green from Aqueous Solutions

NANO ◽  
2021 ◽  
pp. 2150054
Author(s):  
Zongli Ren ◽  
Zhao Yang ◽  
Zhongwei Zhao ◽  
Xuan Yang
Keyword(s):  
Activated Carbon ◽  
Aqueous Solutions ◽  
Malachite Green ◽  
Contact Time ◽  
Negative Impact ◽  
Synthesis Method ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Magnetic Activated Carbon ◽  
The Cost

Malachite green (MG) pollution has a negative impact on human health. At present, the method of removing it is inconvenient to operate and the cost is high, which has aroused widespread concern. In this study, MgO functionalized magnetic activated carbon (MgO-mAC) prepared by the sol–gel method was used to remove MG in water. The physical and chemical properties of MgO-mAC were tested by SEM, TEM, FTIR, XRD, BET and VSM. The effects of adsorbent dosage, solution pH, contact time, initial MG concentration and temperature on adsorption were studied by batch experiments. The adsorption kinetics data is well described by a pseudo-second-order model. The equilibrium data fits the Langmuir isotherm well. When the pH is 8 and the contact time is 360[Formula: see text]min, the maximum adsorption capacity of MG is 3809[Formula: see text]mg[Formula: see text]g[Formula: see text]. In thermodynamic studies, [Formula: see text], [Formula: see text], [Formula: see text], MG adsorption is an endothermic and spontaneous adsorption process. The current synthesis method is simple in operation and cheap in raw materials, which can greatly reduce the cost of synthesis. Hence, the MgO-mAC material will be an effective adsorbent for removing MG from aqueous solutions.

scholarly journals Enhanced adsorption removal of anionic dyes via a facile preparation of amino-functionalized magnetic silica

2017 ◽  
Vol 75 (6) ◽  
pp. 1399-1409 ◽  
Author(s):  
Xiao-Shui Li ◽  
Yu-Han Fan ◽  
Shou-Wen Zhang ◽  
Shi-Hua Qi
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Maximum Adsorption Capacity ◽  
Reactive Black 5 ◽  
Order Kinetic ◽  
Step Method ◽  
Anionic Dyes ◽  
Solution Ph ◽  
Experimental Conditions ◽  
Magnetic Silica

A novel amino-functionalized magnetic silica (Fe3O4@SiO2-NH2) was easily prepared via a one-step method integrating the immobilization of 3-aminopropyltriethoxysilane with a sol-gel process of tetraethyl orthosilicate into a single process. This showed significant improvement in the adsorption capacity of anionic dyes. The product (Fe3O4@SiO2-NH2) was characterized with scanning electron microscopy, Fourier transform infrared spectroscopy, energy dispersive X-ray spectrometry, zeta potential and vibrating sample magnetometry. The adsorption performance of Fe3O4@SiO2-NH2 was then tested by removing acid orange 10 (AO10) and reactive black 5 (RB5) from the aqueous solutions under various experimental conditions including initial solution pH, initial dye concentrations, reaction time and temperature. The results indicated that the maximum adsorption capacity of AO10 and RB5 on Fe3O4@SiO2-NH2 was 621.9 and 919.1 mg g−1 at pH 2, respectively. The sorption isotherms fit the Langmuir model nicely. Similarly, the sorption kinetic data were better fitted into the pseudo-second order kinetic model than the pseudo-first order model. In addition, the thermodynamic data demonstrated that the adsorption process was endothermic, spontaneous and physical. Furthermore, Fe3O4@SiO2-NH2 could be easily separated from aqueous solutions by an external magnetic field, and the preparation was reproducible.

scholarly journals Application of date palm trunk fibers as adsorbents for removal of Cd+2 ions from aqueous solutions

2013 ◽  
Vol 3 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Ahmed Al-Ghamdi ◽  
Hosam Altaher ◽  
Waid Omar
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Date Palm ◽  
Agricultural Waste ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Adsorption Method ◽  
Mixing Rate ◽  
Date Palm Fibers

In this research raw date palm trunk fibers were used to adsorb cadmium ions from aqueous solutions. The date palm trunk fibers are considered as agricultural waste which is available in huge quantities in the Kingdom of Saudi Arabia. In order to assess the feasibility and the efficiency of using this as an adsorbent, a series of experiments were conducted in a batch adsorption method. The effects of the process variables such as fiber size, mixing rate, mixing time, temperature, solution pH and adsorbent dose on the adsorption capacity of date palm fibers were studied. The results obtained indicated that the adsorption capacity of Cd2+ increased from 29.06 to 51.1 mg/g as the particle size decreased from 875 to 100 μm. It was found that the adsorption capacity of Cd2+ decreased in the strong acidic medium and increased rapidly as the solution pH increased from 1.69 to 3.71. The adsorption capacity was observed to have an insignificant change on raising the temperature from 12 to 34 °C and increasing of mixing speed from 100 to 500 rpm. Also, one very important finding of this research is that the equilibrium time of the adsorption process is very short. The maximum adsorption capacity was obtained after 10 minutes.

Removal of Cu(II) Ions from Aqueous Solutions by Adsorption onto Natural Bentonites

2015 ◽  
Vol 244 ◽  
pp. 205-212 ◽  
Author(s):  
Zuzana Melichová ◽  
Michaela Handzušová
Keyword(s):  
Aqueous Solutions ◽  
Langmuir Isotherm ◽  
Standard Free Energy ◽  
Batch Process ◽  
Effect Of Temperature ◽  
Maximum Adsorption Capacity ◽  
Standard Entropy ◽  
Order Kinetic ◽  
Copper Adsorption ◽  
Flame Atomic Absorption

The removal of Cu (II) ions from aqueous solutions using the adsorption process onto natural Slovak bentonites from deposits Jelšový potok, Hliník nad Hronom and Lieskovec has been investigated in this study. The adsorption experiments were carried out under batch process with initial concentration Cu (II) ions, time and temperature as the variables. A flame atomic absorption spectrometer was used for measuring the copper concentration before and after adsorption. Adsorption was very fast at low coverage and equilibrium was approached within 30 min. The results best fitted the pseudo-second order kinetic model. Langmuir and Freundlich isotherms were applied and isotherm coefficients were computed. The Langmuir isotherm was found to fit better the experimental data measured for used bentonites. The Langmuir maximum adsorption capacity of the adsorbents was from 13.4 to 43.1 mg g−1. The effect of temperature on the equilibrium adsorption of copper from aqueous solution using natural bentonites was investigated at three different temperatures (293, 303 and 313 K). Thermodynamic parameters, such as standard free energy changes (ΔGo), standard enthalpy change (ΔHo) and standard entropy change (ΔSo), were calculated using adsorption equilibrium constant obtained from the Langmuir isotherm. The copper adsorption on bentonite was a spontaneous and endothermic process. The results suggested that natural bentonites are suitable as a adsorbent material for recovery and adsorption of Cu (II) ions from aqueous solutions. Comparing the measured results for used bentonites is evident that for the removal of Cu (II) ions from aqueous solutions is more suitable the bentonite from Jelšový potok.

Synthesis, Characterization and Use of Supported Co/gama-Al2O3 for the Removal of Reactive Blue 19 from Aqueous Solutions

2018 ◽  
Vol 69 (1) ◽  
pp. 228-231
Author(s):  
Maria Larion ◽  
Emil Ioan Muresan ◽  
Cezar Doru Radu ◽  
Ion Sandu ◽  
Angela Cerempei ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Diffuse Reflectance ◽  
Adsorption Process ◽  
Maximum Adsorption Capacity ◽  
Visible Spectroscopy ◽  
Solution Ph ◽  
X Ray ◽  
Reactive Blue 19 ◽  
Uv Visible

In this study, systematic adsorption tests were carried out using Co/gama-Al2O3 adsorbents of different compositions for removal of Reactive Blue 19 dye from aqueous solutions. The adsorbent was characterized by scanning electron microscopy, X-Ray powder diffraction, diffuse reflectance UV-visible spectroscopy and EDX analysis. The influences of several parameters such as pH, adsorbent concentration, adsorption time and dye concentration on the adsorption capacity of g-Al2O3 and Co/g-Al2O3 were investigated. The obtained results indicate that the adsorption is strongly dependent on the solution pH. The maximum adsorption capacity of the Reactive blue 19 dye onto Co/gama-Al2O3 takes place at around pH 2. The adsorption process is fast in the first minutes (95% from the amount of dye being removed after 6 minutes).

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