scholarly journals Photocatalytic Phenol Degradation by Silica-Modified Titanium Dioxide

2021 ◽  
Vol 11 (19) ◽  
pp. 9033
Author(s):  
Diana Rakhmawaty Eddy ◽  
Soraya Nur Ishmah ◽  
Muhamad Diki Permana ◽  
M. Lutfi Firdaus ◽  
Iman Rahayu ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Anatase Phase ◽  
Phenol Degradation ◽  
High Photocatalytic Activity ◽  
Beach Sand ◽  
Order Kinetic ◽  
Particle Size Analyzer ◽  
Bet Analysis ◽  
Order Kinetic Model ◽  
Supporting Material

Titanium dioxide (TiO2) has been widely applied as a photocatalyst for wastewater treatment due to its high photocatalytic activity and it can remove various harmful organic pollutants effectively. Under heated system, however, TiO2 is prone to agglomeration that decrease its abilities as a photocatalyst. In order to overcome the agglomeration and increase its thermal resistance, addition of silica (SiO2) as supporting material is proposed in this research. Silica or silicon dioxide can be extracted from natural resources such as beach sand. Here, we report the application of a composite photocatalyst of TiO2/SiO2 to remove phenolic compounds in wastewater. The photocatalyst was synthesized by adding SiO2 from beach sand onto TiO2 through impregnation methods. The results of the X-ray diffraction (XRD) showed that TiO2 was present in the anatase phase. The highest crystallinity was obtained by TiO2/SiO2 ratios of 7:1. SEM results showed that the shape of the particles was spherical. Further characterizations were conducted using Fourier-transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) analysis, and a particle size analyzer (PSA). By using the optimized condition, 96.05% phenol was degraded by the synthesized photocatalyst of TiO2/SiO2, under UV irradiation for 120 min. The efficiency of the TiO2/SiO2 is 3.5 times better than commercial TiO2 P25 for the Langmuir–Hinshelwood first-order kinetic model.

Synthesis of Functionalized Magnetite Titanium Dioxide Nanocomposite for Removal of Acid Fuchsine Dye

2018 ◽  
Vol 21 (8) ◽  
pp. 583-593 ◽  
Author(s):  
Sara Rahnama ◽  
Shahab Shariati ◽  
Faten Divsar
Keyword(s):  
Titanium Dioxide ◽  
Removal Efficiency ◽  
Magnetic Core ◽  
Fractional Factorial ◽  
Order Kinetic ◽  
Sorption Data ◽  
Salt Addition ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Ft Ir

Objective: In this research, a novel magnetite titanium dioxide nanocomposite functionalized by amine groups (Fe3O4@SiO2@TiO2-NH2) was synthesized and its ability for efficient removal of Acid Fuchsine as an anionic dye from aqueous solutions was investigated. Method: The core-shell structure of Fe3O4@SiO2@TiO2 was prepared using Fe3O4 as magnetic core, tetra ethyl orthosilicate as silica and tetra butyl titanate as titanium source for shell. The synthesized nanocomposites (particle size lower than 44 nm) were characterized by FT-IR, XRD, DRS, SEM and TGA instruments. The various experimental parameters affecting dye removal efficiency were investigated and optimized using Taguchi fractional factorial design. Results: The synthesized adsorbent showed the highest removal efficiency of Acid Fuchsine (99 %) at pH= 3.5, without salt addition and during stirring at contact times less than 10 minutes. The study of kinetic models at two concentration levels showed the fast dye sorption on the surface of proposed nanocomposites with pseudo second order kinetic model (R2=1). Also, the fitting of Acid Fuchsine sorption data to Freundlich, Langmuir and Temkin isotherms suggested that Freundlich model gave a better fitting than other models (R2=0.9936, n=2). Conclusion: Good chemical stability, excellent magnetic properties, very fast adsorption kinetics and high removal efficiency make the synthesized nanocomposite as a proper recoverable sorbent for removal of Acid Fuchsine dye from wastewaters.

scholarly journals Decolourization of malachite green dye by mentha plant biochar (MPB): a combined action of adsorption and electrochemical reduction processes

2018 ◽  
Vol 77 (6) ◽  
pp. 1734-1743 ◽  
Author(s):  
Abhay Prakash Rawat ◽  
D. P. Singh
Keyword(s):  
Malachite Green ◽  
Electron Transfer Reaction ◽  
Order Kinetic ◽  
Voltammetric Analysis ◽  
Malachite Green Dye ◽  
Type Iv ◽  
Bet Analysis ◽  
Order Kinetic Model ◽  
Combined Action ◽  
Adsorption Desorption

Abstract Adsorption behavior of mentha (mint) plant biochar (MPB) in removal of malachite green (MG) dye from aqueous solution was analyzed as a function of different pH (4.0–10.0), initial dye concentration (20–100 mg/L), contact time (0–45 min) and dose of adsorbent (0.05–0.3 g/100 mL). The zeta potential of the MPB particles was found to be −37.9 mV, indicating a negatively charged sorption surface of MPB particles. MPB was found to be more effective in removal of MG dye at pH 6.0 due to combined action of physico-chemisorption and a reductive electron transfer reaction. Results on the Brunauer–Emmett–Teller (BET) analysis of the N2 adsorption–desorption isotherm of MPB as adsorbent showed sigmoidal shape similar to the type IV isotherm and mesoporous nature. The cyclic voltammetric analysis of MG dye showed a reversible, coupled redox reaction at the interface of dye molecules and MPB particles. The maximum monolayer adsorption capacity (qmax) of MPB was found to be 322.58 mg g−1. The separation factor (RL) value was between 0 and 1, indicating a favourable adsorption of MG dye onto MPB. The results fitted well to a pseudo-second-order kinetic model. Further results from desorption experiments showed recovery of MG dye by about 50% in the presence of 1 N HCl.

scholarly journals A novel activated carbon prepared from grapefruit peel and its application in removal of phenolic compounds

2018 ◽  
Vol 77 (10) ◽  
pp. 2517-2527 ◽  
Author(s):  
Xiao Liu ◽  
Yibei Wan ◽  
Penglei Liu ◽  
Yanzhen Fu ◽  
Weihua Zou
Keyword(s):  
Activated Carbon ◽  
Phenolic Compounds ◽  
Contact Time ◽  
Order Kinetic ◽  
Initial Concentration ◽  
Bet Analysis ◽  
Order Kinetic Model ◽  
Grapefruit Peel ◽  
Pseudo Second Order ◽  
Activating Agent

Abstract The most ideal conditions for preparing activated carbon from grapefruit peel (GPAC) were studied using NH4H2PO4 as a chemical activating agent and the obtained material was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Brunauer–Emmett–Teller (BET) analysis. The adsorption capacity of the resulting material has been checked using three phenolic compounds (pyrocatechol (CA), 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP)). The adsorption characteristics of phenolic compounds from aqueous solution by GPAC have been investigated as a function of contact time, pH, initial concentration and temperature. The equilibrium experimental data fitted well with Freundlich and Koble–Corrigan isotherms. The adsorption of the three phenolic compounds on GPAC fitted well with pseudo-second-order kinetic model. Different thermodynamic parameters were also evaluated and it was found that the adsorption was spontaneous, feasible and endothermic in nature. Adsorbents were regenerated by 0.1 mol/L NaOH and GPAC could be reused in phenolic compounds removal.

scholarly journals Chitosan/Phosphate Rock-Derived Natural Polymeric Composite to Sequester Divalent Copper Ions from Water

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2028
Author(s):  
Rachid El Kaim Billah ◽  
Moonis Ali Khan ◽  
Saikh Mohammad Wabaidur ◽  
Byong-Hun Jeon ◽  
Amira AM ◽  
...  
Keyword(s):  
Phosphate Rock ◽  
Copper Ions ◽  
Polymeric Composite ◽  
Ternary Systems ◽  
Order Kinetic ◽  
Divalent Copper ◽  
Significant Drop ◽  
Bet Analysis ◽  
Adsorption Data ◽  
Order Kinetic Model

Herein, a chitosan (CH) and fluroapatite (TNP) based CH-TNP composite was synthesized by utilizing seafood waste and phosphate rock and was tested for divalent copper (Cu(II)) adsorptive removal from water. The XRD and FT-IR data affirmed the formation of a CH-TNP composite, while BET analysis showed that the surface area of the CH-TNP composite (35.5 m2/g) was twice that of CH (16.7 m2/g). Mechanistically, electrostatic, van der Waals, and co-ordinate interactions were primarily responsible for the binding of Cu(II) with the CH-TNP composite. The maximum Cu(II) uptake of both CH and CH-TNP composite was recorded in the pH range 3–4. Monolayer Cu(II) coverage over both CH and CH-TNP surfaces was confirmed by the fitting of adsorption data to a Langmuir isotherm model. The chemical nature of the adsorption process was confirmed by the fitting of a pseudo-second-order kinetic model to adsorption data. About 82% of Cu(II) from saturated CH-TNP was recovered by 0.5 M NaOH. A significant drop in Cu(II) uptake was observed after four consecutive regeneration cycles. The co-existing ions (in binary and ternary systems) significantly reduced the Cu(II) removal efficacy of CH-TNP.

scholarly journals Facile Controlling of the Physical Properties of Zinc Oxide and Its Application to Enhanced Photocatalysis

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Tuan Vu Anh ◽  
Thi Anh Tuyet Pham ◽  
Van Hung Mac ◽  
Thanh Hung Nguyen
Keyword(s):  
Physical Properties ◽  
Synthesis Method ◽  
Catalytic Performance ◽  
High Photocatalytic Activity ◽  
Spherical Particles ◽  
Bandgap Energy ◽  
Order Kinetic ◽  
The Hierarchical Structure ◽  
Order Kinetic Model ◽  
Carnation Flower

In this study, the physical properties of ZnO were facile controlled by the synthesis method with the addition of capping and precipitation agents. As-prepared ZnO samples had different morphologies such as carnation flower-like ZnO (CF-ZnO), rose-flower-like ZnO (RF-ZnO), rod-like ZnO (R-ZnO), and nanoparticle ZnO (N-ZnO) and were characterized by SEM, XRD, N2 adsorption/desorption isotherms, FT-IR, and DR/UV-vis. All samples had a crystallite structure of hexagonal wurtzite type. The CF-ZnO and RF-ZnO samples had the hierarchical structure like a carnation flower and a beautiful rose, respectively. R-ZnO was composed of many hexagonal rods and few spherical particles, while N-ZnO microstructures were made up of nanoparticles with approximately 20–30 nm, exhibiting the largest surface area, pore volume, and pore width among as-prepared samples, and their crystal size and bandgap energy were 17.8 nm and 3.207 eV, respectively. The catalytic performances of ZnO samples were evaluated by degradation of Tartrazine (TA) and Caffeine (CAF) under low UV irradiation (15 W). N-ZnO showed a high photocatalytic activity compared to other samples. Besides, the reaction kinetics was investigated by the first-order kinetic model, and the catalytic performance of ZnO was evaluated through several organic pollutants.

scholarly journals Adsorption of Sb (III) on Oxidized Exfoliated Graphite Nanoplatelets

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 992 ◽  
Author(s):  
Luiza Capra ◽  
Mihaela Manolache ◽  
Ion Ion ◽  
Rusandica Stoica ◽  
Gabriela Stinga ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Contact Time ◽  
Exfoliated Graphite ◽  
Order Kinetic ◽  
Graphite Nanoplatelets ◽  
Adsorption Parameters ◽  
Transmission Electron ◽  
Bet Analysis ◽  
Order Kinetic Model ◽  
Exfoliated Graphite Nanoplatelets

In this work, Sb (III) adsorption on oxidized exfoliated graphite nanoplatelets (ox-xGnP) was evaluated for the first time, to the best of our knowledge. The ox-xGnP were characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), Brunauer–Emmet–Teller (BET) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM) equipped with energy-dispersive X-ray spectroscopy (EDX), and Zeta potential analysis. The adsorption parameters, such as pH and contact time, were optimized, and the best adsorption capacity obtained was 8.91 mg g−1 at pH = 7.0, 1.0 mg ox-xGnP/100 mL solution, T = 293 K, 1.0 mg L−1, Sb (III), 25 min contact time. The best correlation of the kinetic data was described by a pseudo-first-order kinetic model, with R2 = 0.999. The adsorption isotherms of Sb (III) onto ox-xGnP were best described by the Langmuir isotherm model. The thermodynamic parameters showed that the adsorption process was exothermic and spontaneous.

scholarly journals Adsorption Performance of Amino Functionalized Magnetic Molecular Sieve Adsorbent for Effective Removal of Lead Ion from Aqueous Solution

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2353
Author(s):  
Chuanen Guo ◽  
Yingying Wang ◽  
Fangzheng Wang ◽  
Yaoguang Wang
Keyword(s):  
Aqueous Solution ◽  
Lead Ion ◽  
Order Kinetic ◽  
Freundlich Model ◽  
X Ray ◽  
First Order ◽  
Effective Removal ◽  
Layer Adsorption ◽  
Bet Analysis ◽  
Order Kinetic Model

Lead ion (Pb2+) has high toxicity and brings great harm to human body. It is very important to find an effective method to address lead ion pollution. In this work, amino functionalized CoFe2O4/SBA–15 nanocomposite (NH2–CoFe2O4/SBA–15) was prepared for the effective removal of Pb2+ from aqueous solution. The prepared NH2–CoFe2O4/SBA–15 adsorbent was manifested by using scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectrum (FTIR), X-ray powder diffraction (XRD), and Brunauer-Emmett-Teller (BET) analysis. In the meantime, the adsorption conditions, including pH, adsorbent dosage, and adsorption time, were studied. The investigation of adsorption kinetics revealed that the adsorption results conform to the pseudo-first-order kinetic model. The adsorption isotherms research displayed that the adsorption was consistent with the Freundlich model, demonstrating that the adsorption for Pb2+ with the prepared adsorbent was a multimolecular layer adsorption process. In addition, the thermodynamic investigations (ΔG < 0, ΔH > 0, ΔS > 0) demonstrated that the adsorption for Pb2+ with the prepared adsorbent was endothermic and spontaneous. Moreover, the prepared adsorbent showed superior anti-interference performance and reusability, implying the potential application of the adsorbent in actual water treatment. Furthermore, this research may provide a reference and basis for the study of other heavy metal ions.

scholarly journals The degradation of phenol in water solution by TiO2 photocatalysis in a helical reactor

2013 ◽  
Vol 10 (3) ◽  
pp. 404-418 ◽  
Keyword(s):  
Titanium Dioxide ◽  
Light Intensity ◽  
Uv Irradiation ◽  
Photocatalytic Oxidation ◽  
Irradiation Time ◽  
Water Solution ◽  
Phenol Degradation ◽  
Flow Mode ◽  
Order Kinetic ◽  
Wide Range

Heterogeneous photocatalysis is an advanced oxidation process (AOP) which has been widely studied by numerous researchers in the world and is used to degrade or remove a wide range of pollutants in water and air. The photocatalytic oxidation and mineralization of phenol in aqueous catalyst suspensions of titanium dioxide (TiO2) Degussa P25 (80% anatase, 20% rutile) has been carried out in a helical reactor. The photodegradation was investigated using two kinds of high pressure mercury irradiation lamps one emitting at 254 nm (15 Watts) and the other emitting at 365 nm (400 Watts). The effects of the recirculation flow, source of withdrawal, initial phenol concentration, amount of catalyst, suspension pH and light intensity on photodegradation of phenol were investigated. These parameters were studied to find the optimal conditions for a complete and fast oxidation of this organic compound. Kinetic experiments were performed at 32 oC over a range of phenol concentrations from 2.5 to 25 mg l-1, a range of TiO2 concentrations from 0.1 to 1 g l1, a range of suspensions pH from 3 to 9. The helical reactor was operated under a continuous flow-mode. Results showed that photodegradation is an effective method for the removal of phenol from wastewaters. The efficiency of the process depends strongly on the experimental conditions. The amount of catalyst, UV irradiation time, pH and light intensity were important parameters in the degradation process. The rate constants for the different parameters (TiO2, phenol concentration) were evaluated. Kinetic studies showed that titanium dioxide photocatalyst P25 was very active in phenol degradation; we observed that 99% of pollutant was degraded after 6 hours of UV irradiation; furthermore, we observed that phenol degradation was more effective under acidic conditions than alkaline. The kinetics were described by the Langmuir- Hinshelwood (L-H) kinetic model. An overall pseudo-first order kinetic constant has been calculated for phenol conversion and values obtained in acidic pH are higher than those calculated for basic pH media.

scholarly journals Equilibrium and Isotherm Modeling of Toxic dye Adsorption onto Modified Apricot Stone

2018 ◽  
Vol 1 (1) ◽  
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Dye Adsorption ◽  
Acid Activation ◽  
Order Kinetic ◽  
Bet Analysis ◽  
Effects Of Ph ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Ft Ir

In the present study, adsorption of toxic dye Diret red 28 (acid benzidinediazo-bis-1- naphtylamine - 4- sulfonique) from aqueous solution was investigated using activated carbon synthesized with Phosphoric Acid activation. The synthesized adsorbent was analyzed using BET, FT-IR and SEM techniques. The BET analysis showed that the area provided by the synthesized activated carbon was 88.01 m2 g-1. The adsorption isotherms of Toxic dye onto ASAC are determined and correlated with common isotherms equations. The smaller RMSE values obtained for the Langmuir and Dubinin-R models indicate the better curves fitting, the monolayer adsorption capacity of toxic dye is found to be 32.85 mg.g-1 at temperature 25 o C and 23.42 mg.g-1 at temperature 65 o C at pH 13. The adsorption of toxic dye was carried out using a batch system and the effects of pH, contact time, adsorbent dosage, initial concentration and temperature on the adsorption capacity of synthesized adsorbent were investigated. Kinetics studies proved that for both metals, the kinetic data follows the pseudo second order kinetic model. In addition, the thermodynamics studies proved that the adsorption process of toxic dye could be considered spontaneous and endothermic.

Preparation of Titanium-Oxide-Coated Polypropylene Granules for Photooxidation of Organic Pollutant

2013 ◽  
Vol 717 ◽  
pp. 101-107
Author(s):  
H.S. Shin ◽  
D.S. Rhee
Keyword(s):  
Methylene Blue ◽  
Titanium Dioxide ◽  
Organic Pollutant ◽  
Solar Irradiation ◽  
Order Kinetic ◽  
First Order ◽  
Degradation Rates ◽  
Order Kinetic Model ◽  
Flow Through ◽  
Pseudo First Order

Titanium dioxide was coated onto buoyant polypropylene granules. Titanium dioxide coated polypropylene granules (TCPG) had high mechanical and attritional stability as well as appreciable photocatalytic activity under solar irradiation. Chosen model pollutant, Methylene Blue (MB) could be totally decolorized and partially mineralized within 3 h of treatment. TCPG might successfully be applied as suspended in the column flow-through system. Degradation rates depended strongly on pH, initial dye concentration, and optimal media dosage, following pseudo-first-order kinetic model.

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