scholarly journals Engineering Commercial TiO2 Powder into Tailored Beads for Efficient Water Purification

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 326
Author(s):  
George V. Theodorakopoulos ◽  
Fotios K. Katsaros ◽  
Sergios K. Papageorgiou ◽  
Margarita Beazi-Katsioti ◽  
George Em. Romanos
Keyword(s):  
Adsorption Capacity ◽  
Metal Binding ◽  
Structural Characteristics ◽  
Organic Pollutant ◽  
Pyrolytic Carbon ◽  
Local Concentration ◽  
Batch Experiments ◽  
Treatment Conditions ◽  
Degussa P25 ◽  
Synthesis Procedure

In this study, efficient commercial photocatalyst (Degussa P25) nanoparticles were effectively dispersed and stabilized in alginate, a metal binding biopolymer. Taking advantage of alginate’s superior metal chelating properties, copper nanoparticle-decorated photocatalysts were developed after a pyrolytic or calcination-sintering procedure, yielding ceramic beads with enhanced photocatalytic and mechanical properties, excellent resistance to attrition, and optimized handling compared to powdered photocatalysts. The morphological and structural characteristics were studied using LN2 porosimetry, SEM, and XRD. The abatement of an organic pollutant (Methyl Orange, MO) was explored in the dark and under UV irradiation via batch experiments. The final properties of the photocatalytic beads were defined by both the synthesis procedure and the heat treatment conditions, allowing for their further optimization. It was found that the pyrolytic carbon residuals enabled the adhesion of the TiO2 nanoparticles, acting as binder, and increased the MO adsorption capacity, leading to increased local concentration in the photocatalyst vicinity. Well dispersed Cu nanoparticles were also found to enhance photocatalytic activity. The prepared photocatalysts exhibited increased MO adsorption capacity (up to 3.0 mg/g) and also high photocatalytic efficiency of about 50% MO removal from water solutions, reaching an overall MO rejection of about 80%, at short contact times (3 h). Finally, the prepared photocatalysts kept their efficiency for at least four successive photocatalytic cycles.

scholarly journals Synthesis and characterization of one-dimensional titanate structure

2008 ◽  
Vol 2 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Ljubica Nikolic ◽  
Marija Maletin ◽  
Paula Ferreira ◽  
Paula Vilarinho
Keyword(s):  
Heat Treatment ◽  
Structural Characteristics ◽  
Hydrothermal Process ◽  
Synthesis And Characterization ◽  
One Dimensional ◽  
Treatment Conditions ◽  
Alkaline Conditions ◽  
The Stability ◽  
Simple Hydrothermal Process

One-dimensional titania structures were synthesized trough a simple hydrothermal process in a highly alkaline conditions. The aim of this work was to elucidate the effect of time on the formation of 1D titanates as well on its structural characteristics (morphology, phase composition, surface area). Apart from that, the effect of heat treatment conditions on the stability of titanate based 1D samples has been investigated. The results have revealed that it is possible to form one-dimensional titanates already after 1 hour of hydrothermal synthesis. Although the composition of titanates is still under debate, the results probably correspond to the layered sodium titanates. The 1D prepared structures show a remarkable stability during heating, remaining the basic morphology and composition even up to 700?C.

scholarly journals Innovative Low-Cost Carbon/ZnO Hybrid Materials with Enhanced Photocatalytic Activity towards Organic Pollutant Dyes’ Removal

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1873
Author(s):  
Petronela Pascariu ◽  
Niculae Olaru ◽  
Aurelian Rotaru ◽  
Anton Airinei
Keyword(s):  
Photocatalytic Activity ◽  
Hybrid Materials ◽  
Raw Materials ◽  
Structural Characteristics ◽  
Low Cost ◽  
Organic Pollutant ◽  
Zno Nanostructures ◽  
Zno Nanocrystals ◽  
Electrospinning Method ◽  
New Type

A new type of material based on carbon/ZnO nanostructures that possesses both adsorption and photocatalytic properties was obtained in three stages: cellulose acetate butyrate (CAB) microfiber mats prepared by the electrospinning method, ZnO nanostructures growth by dipping and hydrothermal methods, and finally thermal calcination at 600 °C in N2 for 30 min. X-ray diffraction (XRD) confirmed the structural characteristics. It was found that ZnO possesses a hexagonal wurtzite crystalline structure. The ZnO nanocrystals with star-like and nanorod shapes were evidenced by scanning electron microscopy (SEM) measurements. A significant decrease in Eg value was found for carbon/ZnO hybrid materials (2.51 eV) as compared to ZnO nanostructures (3.21 eV). The photocatalytic activity was evaluated by studying the degradation of three dyes, Methylene Blue (MB), Rhodamine B (RhB) and Congo Red (CR) under visible-light irradiation. Therefore, the maximum color removal efficiency (both adsorption and photocatalytic processes) was: 97.97% of MB (C0 = 10 mg/L), 98.34% of RhB (C0 = 5 mg/L), and 91.93% of CR (C0 = 10 mg/L). Moreover, the value of the rate constant (k) was found to be 0.29 × 10−2 min−1. The novelty of this study relies on obtaining new photocatalysts based on carbon/ZnO using cheap and accessible raw materials, and low-cost preparation techniques.

scholarly journals Catalysis of Organic Pollutants Abatement Based on Pt-Decorated Ag@Cu2O Heterostructures

Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2721
Author(s):  
Xiaolong Zhang ◽  
Bingbing Han ◽  
Yaxin Wang ◽  
Yang Liu ◽  
Lei Chen ◽  
...  
Keyword(s):  
Catalytic Reduction ◽  
Structural Characteristics ◽  
Organic Pollutant ◽  
Pt Nanoparticles ◽  
Catalytic Performance ◽  
Pt Nanoparticle ◽  
Local Surface ◽  
Local Surface Plasmon Resonance ◽  
Cu2o Nanoparticles ◽  
Excellent Catalytic Performance

Pt-decorated Ag@Cu2O heterostructures were successfully synthesized using a simple and convenient method. The Pt nanoparticle density on the Ag@Cu2O can be controlled by changing the concentration of the Pt precursor. The synthesized Ag@Cu2O–Pt nanoparticles exhibited excellent catalytic performance, which was greatly affected by changes in the Ag@Cu2O–Pt structure. To optimize the material’s properties, the synthesized Ag@Cu2O–Pt nanoparticles were used to catalyze toxic pollutants and methyl orange (MO), and nontoxic products were obtained by catalytic reduction. The Pt-decorated Ag@Cu2O nanoparticles showed excellent catalytic activity, which significantly decreased the pollutant concentration when the nanoparticles were used for catalytic reduction. The redistribution of charge transfer is the nanoparticles’ main contribution to the catalytic degradation of an organic pollutant. This Pt-decorated Ag@Cu2O material has unique optical and structural characteristics that make it suitable for photocatalysis, local surface plasmon resonance, and peroxide catalysis.

Use of phytofiltration technologies in the removal of heavy metals: A review

2004 ◽  
Vol 76 (4) ◽  
pp. 801-813 ◽  
Author(s):  
J. L. Gardea-Torresdey ◽  
G. de la Rosa ◽  
J. R. Peralta-Videa
Keyword(s):  
Chemical Modification ◽  
Adsorption Capacity ◽  
Metal Binding ◽  
Precious Metals ◽  
Spectroscopic Studies ◽  
Column Studies ◽  
Biosorption Process ◽  
Removal Of Heavy Metals ◽  
Aqueous Effluents ◽  
Amino Amide

Biosorption is a relatively new process that has proven very promising in the removal of contaminants from aqueous effluents. Microorganisms as well as plant- and animal-derived materials have been used as biosorbents by many researchers. Biomaterial immobilization and chemical modification improves the adsorption capacity and stability of biosorbents. Biosorption experiments over Cu(II), Cd(II), Pb(II), Cr(III), and Ni(II) demonstrated that biomass Cu(II) adsorption ranged from 8.09 to 45.9 mg g−1, while Cd(II) and Cr(VI) adsorption ranged from 0.4 to 10.8 mg g−1 and from 1.47 to 119 mg g−1, respectively. Mechanisms involved in the biosorption process include chemisorption, complexation, surface and pore adsorption-complexation, ion exchange, microprecipitation, hydroxide condensation onto the biosurface, and surface adsorption. Chemical modification and spectroscopic studies have shown that cellular components including carboxyl, hydroxyl, sulfate, sulfhydryl, phosphate, amino, amide, imine, and imidazol moieties have metal binding properties and are therefore the functional groups in the biomass. Column studies using support matrices for biomass immobilization such as silica, agar, polyacrilamide, polysulfone, alginates, cellulase, and different cross-linking agents have been performed to improve the biomass adsorption capacity and reusability. In this review, the salient features of plant-derived materials are highlighted as potential phytofiltration sources in the recovery of toxic heavy and precious metals.

scholarly journals Bioadsorption of lead(II) over the pulp of Acrocomia aculeata

2021 ◽  
Vol 46 (4) ◽  
pp. 38-46
Author(s):  
Alexandra Novak ◽  
F�tima Yubero ◽  
Diana Diez-P�rez-N��ez ◽  
Fernando Luis Fertonani ◽  
Brenda Gisselle Da Silva Britez ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Adsorption Capacity ◽  
Freundlich Isotherm ◽  
Column Experiments ◽  
Maximum Adsorption Capacity ◽  
Batch Experiments ◽  
Adsorption Data ◽  
Acrocomia Aculeata ◽  
Scanning Electron

The adsorption of lead in aqueous solution onto Acrocomia aculeata pulp was examined. The pulp was characterized in the presence and absence of lead using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG-DTA), and scanning electron microscopy (SEM). Sulfur and oxygen bonds were responsible for adsorbing lead onto the pulp surface. The TG-DTA profile proved that adding sodium azide increases the pulp�s thermal stability until 200 �C. Adsorption data in batch and column systems were analyzed to understand the pulp adsorption compared to other biomaterials. In the batch experiments, the removal efficiency reached a maximum of 91.9% when a solution of 50 ppm of lead was placed in contact with the pulp for 30 min and fit Freundlich isotherm behavior. In the column experiments, the theoretical maximum adsorption capacity was found to be 11.97 mg g�1; more column data is needed to compare column results to other studies. Further studies to improve the pulp adsorption capacity are needed for it to be a competitive biomaterial for water treatment.

scholarly journals Noble metal binding on macroporous poly(GMA-co-EGDMA) modified with ethylenediamine

2004 ◽  
Vol 69 (6) ◽  
pp. 455-460 ◽  
Author(s):  
Aleksandra Nastasovic ◽  
Slobodan Jovanovic ◽  
Dragica Jakovljevic ◽  
Slavka Stankovic ◽  
Antonije Onjia
Keyword(s):  
Ethylene Glycol ◽  
Sorption Capacity ◽  
Metal Binding ◽  
Glycidyl Methacrylate ◽  
Sorption Rate ◽  
Glycol Dimethacrylate ◽  
Batch Experiments ◽  
Uptake Capacity ◽  
Epoxy Groups ◽  
Suspension Copolymerization

Macroporous crosslinked poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate), p(GME), was synthesized by suspension copolymerization and modified by reaction of the pendant epoxy groups with ethylenediamine. The sorption rate and capacity of themodified copolymer, p(GME)-en for Rh(III) Au(III) and Pt(IV) ions were determined in batch experiments under non-competitive conditions. The uptake of Rh(III) was faster than those ofAu(III) and Pt(IV). The sorption capacity for Pt(IV)was determined in the pHrange 0.9?6.0. The maximum Pt(IV) uptake capacity onto p(GME)-en at pH 5.5 was 1.30 mmol/g.

scholarly journals ISOTERM ADSORPSI FENOL OLEH LEMPUNG ALAM

2019 ◽  
Vol 7 (1) ◽  
pp. 029
Author(s):  
Nelly Wahyuni ◽  
Imelda H. Silalahi ◽  
Dina Angelina
Keyword(s):  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Contact Time ◽  
Freundlich Isotherm ◽  
Langmuir Adsorption Isotherm ◽  
Batch Experiments ◽  
Natural Clay ◽  
Langmuir Adsorption ◽  
Equilibrium Data ◽  
Initial Phenol Concentration

Abstrak Fenol merupakan polutan yang sangat berbahaya di lingkungan karena bersifat racun dan sulit terdegradasi oleh organisme pengurai. Lempung alam yang berasal dari Kecamatan Capkala, Kabupaten Bengkayang  akan dikaji penggunaannya sebagai adsorben fenol. Adsorpsi dilakukan dengan metoda batch pada variasi waktu kontal dan konsentrasi awal fenol. Data kesetimbangan adsorpsi diuji dengan isoterm Langmuir dan Freundlich. Hasil penelitian menunjukkan waktu kontak optimum adsorpsi adalah 4 jam. Proses adsorpsi fenol  oleh lempung alam  mengikuti model isoterm adsorpsi Langmuir dengan kapasitas adsorpsi sebesar 0,65mg/g. Kata Kunci: fenol, Freundlich, isoterm adsorpsi, Langmuir, lempung alamAbstract Phenol is a pollutant that is very dangerous in the environment because it is toxic and difficult to degrade by decomposing organisms. Natural clay from Capkala District, Bengkayang Regency will be studied as phenol adsorbent. Batch experiments were carried out by varying the parameters like contact time of adsorption and initial phenol concentration. The equilibrium data were tested with Langmuir and Freundlich isotherm. The results showed that the optimum contact time for adsorption was 4 hours. The process of adsorption of phenol by natural clay follows the Langmuir adsorption isotherm model with an adsorption capacity of 0.65mg/g.  Keywords: adsorption isotherm, Freundlich, natural clay, phenol, Langmuir.

scholarly journals Adsorption Characteristics of Oxytetracycline by Different Fractions of the Organic Matter from Humus Soil: Insight from Internal Structure and Composition

2020 ◽  
Vol 17 (3) ◽  
pp. 914
Author(s):  
Mengya Luo ◽  
Shengke Yang ◽  
Siqi Shen ◽  
Yu Li
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Adsorption Capacity ◽  
Internal Structure ◽  
Batch Experiments ◽  
N2 Adsorption ◽  
Sem Images ◽  
Organic Fractions ◽  
Adsorption Desorption ◽  
Humus Soil

For minimizing the transport of antibiotics to groundwater, the migration of antibiotics in soils should be investigated. Soil organic matter can affect the migration of antibiotics. To date, the influence of aromatics and aliphatic content of organic matter on the adsorption of antibiotics has been controversial. To better understand the reaction mechanism of soil organic matter with antibiotics, this study investigated the adsorption of oxytetracycline (OTC) by humus soils (HOS) and their fractions. HOS were sequentially fractionated into four organic fractions, including the removal of dissolved organic matter (HRDOM), removal of minerals (HRM), removal of free fat (HRLF), and nonhydrolyzable organic carbon (HNHC). Moreover, batch experiments revealed that adsorption capacity was ordered by HNHC > HOS > HRDOM > HRLF > HRM. SEM images and N2 adsorption/desorption isotherms indicate that adsorption capacity is independent of the external structure. However, adsorption capacity is related to the internal structure and composition. Combination analysis with elemental composition and infrared spectroscopy showed that the adsorption capacity of HRM, HRLF, and HNHC had a good positive correlation with aromaticity, but a negative correlation with polarity and hydrophilicity. Additionally, the rule of binding affinity between OTC and functional groups with different properties was summarized as aromatic > polarity > hydrophilic.

Graft copolymerization of acrylic acid on kraft lignin to enhance aniline adsorption from aqueous solution

TAPPI Journal ◽  
2019 ◽  
Vol 18 (01) ◽  
pp. 75-84
Author(s):  
Xinyi Jiang ◽  
Guanhua Wang ◽  
Qingjun Liu ◽  
Chuanling Si
Keyword(s):  
Aqueous Solution ◽  
Acrylic Acid ◽  
Adsorption Capacity ◽  
Graft Copolymerization ◽  
Organic Pollutant ◽  
Kraft Lignin ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Copolymer Structure ◽  
Modified Lignin

Kraft lignin from bamboo was modified by grafting with acrylic acid to improve its capacity to adsorb aniline, a typical aromatic organic pollutant. Characterization of the copolymer structure and morphology indicated that lignin was successfully grafted by acrylic acid. Batch experiments showed that after graft copolymerization, the modified lignin had an enhanced aniline adsorption capacity (89.89 mg/g) as compared with the original lignin (6.61 mg/g). A kinetics study showed that the adsorption process followed pseudo-second-order kinetics, and the activation energy (Ea) was 10.22 kJ/mol. The equilibrium data were consistent with the Langmuir equation. The maximum monolayer capacity was 108.7 mg/g, which is higher than those of most reported lignin-based adsorbents. Thermodynamic values indicated that adsorption of aniline on the modified lignin is an exothermic process and spontaneous in nature due to the negative value of ΔH and ΔG. Consequently, graft copolymerization of acrylic acid on lignin appears to be a promising modification process to enhance the aniline adsorption capacity from aqueous solution.

Influence of the Anatase/Rutile Ratio on the TiO2 Photocatalytic Activity for the Photodegradation of Light Hydrocarbons

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
Virginia Collins-Martínez ◽  
Alejandro López Ortiz ◽  
Alfredo Aguilar Elguézabal
Keyword(s):  
Photocatalytic Activity ◽  
Adsorption Capacity ◽  
Reaction Rate ◽  
Water Adsorption ◽  
Rutile Phase ◽  
Reaction Rate Constant ◽  
Light Hydrocarbons ◽  
Different Temperatures ◽  
Degussa P25 ◽  
Intrinsic Reaction Rate

A set of TiO2 samples with different anatase/rutile ratios was prepared by calcinations at different temperatures from commercial photocatalyst Degussa P25. The effects of the two crystalline phases of titanium (IV) oxide on the photocatalytic activity in gaseous phase through oxidation of light hydrocarbons were studied. Crystalline phase transformation from anatase to rutile occurred at 700°C for P25. Results indicate that samples with higher anatase/rutile ratios presented higher intrinsic activities for the photodegradation of a propane/isobutane/butane (40/35/25 %V) mixture. However, the activity did not totally disappear after complete crystalline transformation from anatase to rutile, indicating that the pure rutile phase also presents photoactivity. During the photocatalytic reaction of TiO2 samples, a linear dependence was found between the inverse of the intrinsic reaction rate constant (k intrinsic) and the water adsorption capacity in the surface (WAPS) of the synthesized TiO2 catalyst. The thermal treatment used to induce the formation of rutile by calcination would presumably reduce water adsorption capacity and surface area, leading to a decrease in photocatalytic activity.

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