Photocatalytic Treatment of Wastewater Containing Simultaneous Organic and Inorganic Pollution: Competition and Operating Parameters Effects

In the present study, methylene blue (MB) removal from aqueous solutions via the photocatalytic process using TiO2 as a catalyst in the presence of external ultra-violet light (UV) was investigated. The results of adsorption in the absence of UV radiation showed that adsorption reached an equilibrium state at 60 min. The experimental kinetic data were found to be well fitted by the pseudo-second-order model. Furthermore, the isotherm study suggested that dye uptake by TiO2 is a chemisorption process with a maximum retention capacity of 34.0 mg/g. The photodegradation of MB was then assessed under various experimental conditions. The related data showed that dye mineralization decreased when dye concentrations were increased and was favored at high pH values and low salt concentrations. The simultaneous presence of organic and inorganic pollution (Zinc) was also evaluated. The effect of the molar ratio Zn2+/MB+ in the solution at different pH values and NaCl concentrations was also monitored. The corresponding experimental results showed that at low values of Zn2+ in the solution (30 mg/L), the kinetic of the MB removal became faster until reaching an optimum at Zn2+/MB+ concentrations of 60/60 mg/L; it then slowed down for higher concentrations. The solutions’ carbon contents were measured during the degradation process and showed total mineralization after about 5 h for the optimal Zn2+/MB+ condition.

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Pulverized river shellfish shells as a 904 cheap adsorbent for removing of malathion from water: Examination of the isotherms, kinetics, thermodynamics and optimization of the experimental conditions by the response surface method

Vojnotehnicki glasnik ◽

10.5937/vojtehg69-32844 ◽

2021 ◽

Vol 69 (4) ◽

pp. 871-904

Author(s):

Zlate Veličković ◽

Bogdan Vujičić ◽

Vladica Stojanović ◽

Predrag Stojisavljević ◽

Zoran Bajić ◽

...

Keyword(s):

Response Surface ◽

Response Surface Method ◽

Organophosphorus Pesticide ◽

Isothermal Model ◽

Experimental Conditions ◽

Langmuir Adsorption ◽

Ph Values ◽

Surface Method ◽

Adsorption Data ◽

Pseudo Second Order

Introduction/purpose: In this study, we investigated the possibility of removing the organophosphorus pesticide malathion from water using a new adsorbent based on the biowaste of river shell shards from the Anodonta Sinadonta woodiane family, a material that accumulates in large quantities as waste on the banks of large rivers. Two adsorbents were tested - mechanically comminuted river shells (MRM) and mechanosynthetic hydroxyapatite from comminuted river shells (RMHAp). Methods: The obtained adsorbents were characterized and tested for the removal of the organophosphorus pesticide malathion from water. In order to predict the optimal adsorption conditions using the Response Surface Method (RSM), the authors investigated the influence of variable factors (adsorption conditions), pH values, adsorbent doses, contact times, and temperatures on the adsorbent capacity. Results: The best adsorption of malathion was achieved at mean pH values between 6.0 and 7.0. The adsorption data for malathion at 25, 35, and 45 °C were compared using the Langmuir, Freundlich, DubininRadushkevich (DR), and Temkin isothermal models, as well as pseudofirst order, pseudo-second order and Elovic kinetic models for modeling adsorption kinetics. The maximum Langmuir adsorption capacity for MRM and RMHAp at 25 °C was 46,462 mg g-1 and 78,311 mg g-1 , respectively. Conclusion: The results have showed that malathion adsorption on both adsorbents follows the pseudo-second kinetic model and the Freundlich isothermal model. The thermodynamic parameters indicate the endothermic, feasible, and spontaneous nature of the adsorption process.

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Use of Lignite as a Low-Cost Material for Cadmium and Copper Removal from Aqueous Solutions: Assessment of Adsorption Characteristics and Exploration of Involved Mechanisms

Water ◽

10.3390/w13020164 ◽

2021 ◽

Vol 13 (2) ◽

pp. 164

Author(s):

Salah Jellali ◽

Ahmed Amine Azzaz ◽

Mejdi Jeguirim ◽

Helmi Hamdi ◽

Ammar Mlayah

Keyword(s):

Aqueous Solutions ◽

Low Cost ◽

X Ray Diffraction ◽

High Adsorption ◽

Experimental Conditions ◽

X Ray ◽

Ph Values ◽

Adsorption Capacities ◽

Or Groups ◽

Pseudo Second Order

Lignite, as an available and low-cost material, was tested for cadmium (Cd) and copper (Cu) removal from aqueous solutions under various static experimental conditions. Experimental results showed that the removal efficiency of both metals was improved by increasing their initial concentrations, adsorbent dosage and aqueous pH values. The adsorption kinetic was very rapid for Cd since about 78% of the totally adsorbed amounts were removed after a contact time of only 1 min. For Cd and Cu, the kinetic and isothermal data were well fitted with pseudo-second order and Freundlich models, respectively, which suggests that Cd/Cu removal by lignite occurs heterogeneously on multilayers surfaces. The maximum Langmuir’s adsorption capacities of Cd and Cu were assessed to 38.0 and 21.4 mg g−1 and are relatively important compared to some other lignites and raw natural materials. Results of proximate, scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS), Fourier transform infrared spectroscopy (FTIR) and X-Ray diffraction (XRD) showed that the removal of these metals occurs most likely through a combination of cation exchange and complexation with specific functional groups. The relatively high adsorption capacity of the used lignite promotes its future use as a low cost material for Cd and Cu removal from effluents, and possibly for other heavy metals or groups of pollutants.

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Zeolite NaP1 Functionalization for the Sorption of Metal Complexes with Biodegradable N-(1,2-dicarboxyethyl)-D,L-aspartic Acid

Materials ◽

10.3390/ma14102518 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2518

Author(s):

Dorota Kołodyńska ◽

Yongming Ju ◽

Małgorzata Franus ◽

Wojciech Franus

Keyword(s):

Experimental Data ◽

Aspartic Acid ◽

Ph Value ◽

Complexing Agents ◽

X Ray Diffraction ◽

Experimental Conditions ◽

Modified Zeolite ◽

X Ray ◽

Slow Release Fertilizers ◽

Pseudo Second Order

The possibility of application of chitosan-modified zeolite as sorbent for Cu(II), Zn(II), Mn(II), and Fe(III) ions and their mixtures in the presence of N-(1,2-dicarboxyethyl)-D,L-aspartic acid, IDHA) under different experimental conditions were investigated. Chitosan-modified zeolite belongs to the group of biodegradable complexing agents used in fertilizer production. NaP1CS as a carrier forms a barrier to the spontaneous release of the fertilizer into soil. The obtained materials were characterized by Fourier transform infrared spectroscopy (FTIR); surface area determination (ASAP); scanning electron microscopy (SEM-EDS); X-ray fluorescence (XRF); X-ray diffraction (XRD); and carbon, hydrogen, and nitrogen (CHN), as well as thermogravimetric (TGA) methods. The concentrations of Cu(II), Zn(II), Mn(II), and Fe(III) complexes with IDHA varied from 5–20 mg/dm3 for Cu(II), 10–40 mg/dm3 for Fe(III), 20–80 mg/dm3 for Mn(II), and 10–40 mg/dm3 for Zn(II), respectively; pH value (3–6), time (1–120 min), and temperature (293–333 K) on the sorption efficiency were tested. The Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin adsorption models were applied to describe experimental data. The pH 5 proved to be appropriate for adsorption. The pseudo-second order and Langmuir models were consistent with the experimental data. The thermodynamic parameters indicate that adsorption is spontaneous and endothermic. The highest desorption percentage was achieved using the HCl solution, therefore, proving that method can be used to design slow-release fertilizers.

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Grafting of (3-Chloropropyl)-Trimethoxy Silane on Halloysite Nanotubes Surface

Applied Sciences ◽

10.3390/app11125534 ◽

2021 ◽

Vol 11 (12) ◽

pp. 5534

Author(s):

Asmaa M. Abu El-Soad ◽

Giuseppe Lazzara ◽

Alexander V. Pestov ◽

Daria P. Tambasova ◽

Denis O. Antonov ◽

...

Keyword(s):

Active Site ◽

Chemical Engineering ◽

Coupling Reaction ◽

Ammonium Hydroxide ◽

Halloysite Nanotubes ◽

Chemical Activity ◽

Molar Ratio ◽

New Materials ◽

Experimental Conditions ◽

Trimethoxy Silane

Modified halloysite nanotubes (HNTs-Cl) were synthesized by a coupling reaction with (3-chloropropyl) trimethoxysilane (CPTMS). The incorporation of chloro-silane onto HNTs surface creates HNTs-Cl, which has great chemical activity and is considered a good candidate as an active site that reacts with other active molecules in order to create new materials with great applications in chemical engineering and nanotechnology. The value of this work lies in the fact that improving the degree of grafting of chloro-silane onto the HNT’s surface has been accomplished by incorporation of HNTs with CPTMS under different experimental conditions. Many parameters, such as the dispersing media, the molar ratio of HNTs/CPTMS/H2O, refluxing time, and the type of catalyst were studied. The greatest degree of grafting was accomplished by using toluene as a medium for the grafting process, with a molar ratio of HNTs/CPTMS/H2O of 1:1:3, and a refluxing time of 4 h. The addition of 7.169 mmol of triethylamine (Et3N) and 25.97 mmol of ammonium hydroxide (NH4OH) led to an increase in the degree of grafting of CPTMS onto the HNT’s surface.

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Reaktive E=C(p–p)π Systeme, XXXIV Addition von Alkoholen oder primären Aminen an Phosphaalkene F3CP=C(F)OR. Neue Trifluormethylphosphane und -phosphaalkene/Reactive E = C( p – p ) π-Systems, XXXIV Addition of Alcohols or Primary Amines to Phosphaalkenes F3CP= C(F)OR . Novel Trifluoromethylphosphanes and Phosphaalkenes

Zeitschrift für Naturforschung B ◽

10.1515/znb-1993-0114 ◽

1993 ◽

Vol 48 (1) ◽

pp. 58-67 ◽

Cited By ~ 10

Author(s):

Joseph Grobe ◽

Duc Le Van ◽

Gudrun Lange

Keyword(s):

High Resolution Mass Spectrometry ◽

Molar Ratio ◽

Primary Amines ◽

The Novel ◽

Experimental Conditions ◽

Pull System ◽

Fragment Ions ◽

New Compounds ◽

C Nmr

The course of the reactions o f fluorophosphaalkenes F3CP = C (F)OR [R = Me (1), Et (2)] with methanol or ethanol strongly depends on the experimental conditions. Thus at 70 °C a mixture of the 2-phosphapropionic acid ester F3CP (H )CO2R [R = Me (3), Et (4)] and trifluoromethylphosphane H2PCF3 is formed [molar ratio: 3 or 4 /H2 CF3 ≈1/1]. If the precursors F3CP (H )CO2R [R = Me (3), Et) are used as starting materials, the reaction with ROH under the same conditions affords 3 and 4, respectively, (90 to 95% yield) with only traces of H2PCF 3. In the presence o f iPr2NH these precursors react with R′OH to give the novel trifluoromethylphosphaalkenes F3CP = C (OR )OR [R /R′: Me/Me (6); E t/E t (7); Me/Et (8)]. With Et2NH , 3 undergoes an addition/elimination process yielding the interesting push/pull system Et2N(F)C = P-CO2Me (5). 1 and 2 react with primary amines R′NH2 (R′= tBu, Me) with stereoselective formation of the fairly labile phosphaalkenes F3CP = C(OR)NHR′ [R /R′: Me/tBu (9), Et/tBu(10), Me/Me (11)] with trans-positions for CF3 and NHR′.The new compounds 3 -11 were characterized by spectroscopic investigations (1H , 19F, 31P, 13C NMR ; IR, MS) and determination of M+ or typical fragment ions [M+ -OR ] by high resolution mass spectrometry.

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Phosphorus removal from aqueous solution using a novel granular material developed from building waste

Water Science & Technology ◽

10.2166/wst.2017.019 ◽

2017 ◽

Vol 75 (6) ◽

pp. 1500-1511 ◽

Cited By ~ 3

Author(s):

Shengjiong Yang ◽

Pengkang Jin ◽

Xiaochang C. Wang ◽

Qionghua Zhang ◽

Xiaotian Chen

Keyword(s):

Granular Material ◽

Chemical Precipitation ◽

Phosphate Removal ◽

Precipitation Process ◽

Order Kinetic ◽

Solution Ph ◽

Experimental Conditions ◽

Removal Capacity ◽

Order Kinetic Model ◽

Pseudo Second Order

In this study, a granular material (GM) developed from building waste was used for phosphate removal from phosphorus-containing wastewater. Batch experiments were executed to investigate the phosphate removal capacity of this material. The mechanism of removal proved to be a chemical precipitation process. The characteristics of the material and resulting precipitates, the kinetics of the precipitation and Ca2+ liberation processes, and the effects of dosage and pH were investigated. The phosphate precipitation and Ca2+ liberation processes were both well described by a pseudo-second-order kinetic model. A maximum precipitation capacity of 0.51 ± 0.06 mg g−1 and a liberation capacity of 6.79 ± 0.77 mg g−1 were measured under the experimental conditions. The processes reached equilibrium in 60 min. The initial solution pH strongly affected phosphate removal under extreme conditions (pH <4 and pH >10). The precipitates comprised hydroxyapatite and brushite. This novel GM can be considered a promising material for phosphate removal from wastewater.

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Preparation of cationic waste paper and its application in poisonous dye removal

Water Science & Technology ◽

10.2166/wst.2013.140 ◽

2013 ◽

Vol 67 (11) ◽

pp. 2560-2567 ◽

Cited By ~ 8

Author(s):

Fan Yang ◽

Xiaojie Song ◽

Lifeng Yan

Keyword(s):

Low Cost ◽

Aqueous Suspension ◽

Order Kinetic ◽

Acid Orange 7 ◽

Anionic Dyes ◽

Experimental Conditions ◽

Adsorption Models ◽

Acid Orange ◽

Initial Ph ◽

Pseudo Second Order

Cationic paper was prepared by reaction of paper with 2,3-epoxypropyltrimethylammonium chloride in aqueous suspension, and tested as low-cost adsorbent for wastewater treatment. The experimental results revealed that anionic dyes (Acid Orange 7, Acid Red 18, and Acid Blue 92) were adsorbed on the cationic paper nicely. The maximum amount of dye Acid Orange 7 adsorbed on cationic paper was 337.2 mg/g in experimental conditions. The effects of initial dye concentration, temperature, and initial pH of dye solution on adsorption capacity of cationic paper were studied. The pseudo-first-order and pseudo-second-order kinetic models were applied to describe the kinetic data. The Freundlich and Langmuir adsorption models were used to describe adsorption equilibrium. The thermodynamic data indicated that the adsorption process of dye on cationic paper occurred spontaneously.

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Synthesis, Analysis, and Testing of BiOBr-Bi2WO6Photocatalytic Heterojunction Semiconductors

International Journal of Photoenergy ◽

10.1155/2015/630476 ◽

2015 ◽

Vol 2015 ◽

pp. 1-12 ◽

Cited By ~ 21

Author(s):

Xiangchao Meng ◽

Zisheng Zhang

Keyword(s):

Visible Light ◽

Visible Light Irradiation ◽

Degradation Process ◽

Light Irradiation ◽

Enhancement Effect ◽

Electron Hole ◽

Experimental Conditions ◽

Synthesis Conditions ◽

Optimum Synthesis ◽

Photocatalytic Activities

In photocatalysis, the recombination of electron-hole pairs is generally regarded as one of its most serious drawbacks. The synthesis of various composites with heterojunction structures has increasingly shed light on preventing this recombination. In this work, a BiOBr-Bi2WO6photocatalytic heterojunction semiconductor was synthesized by the facile hydrothermal method and applied in the photocatalytic degradation process. It was determined that both reaction time and temperature significantly affected the crystal structure and morphologies of the photocatalysts. BiOBr (50 at%)-Bi2WO6composites were prepared under optimum synthesis conditions (120°C for 6 h) and by theoretically analyzing the DRS results, it was determined that they possessed the suitable band gap (2.61 eV) to be stimulated by visible-light irradiation. The photocatalytic activities of the as-prepared photocatalysts were evaluated by the degradation ofRhodamine B (RhB)under visible-light irradiation. The experimental conditions, including initial concentration, pH, and catalyst dosage, were explored and the photocatalysts in this system were proven stable enough to be reused for several runs. Moreover, the interpreted mechanism of the heterojunction enhancement effect proved that the synthesis of a heterojunction structure provided an effective method to decrease the recombination rate of the electron-hole pairs, thereby improving the photocatalytic activity.

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Phosphorus extracted by ion exchange resins and mehlich-1 from oxisols (latosols) treated with different phosphorus rates and sources for varied soil-source contact periods

Revista Brasileira de Ciência do Solo ◽

10.1590/s0100-06832013000300013 ◽

2013 ◽

Vol 37 (3) ◽

pp. 667-677 ◽

Cited By ~ 17

Author(s):

Irio Fernando de Freitas ◽

Roberto Ferreira Novais ◽

Ecila Mercês de Albuquerque Villani ◽

Sarah Vieira Novais

Keyword(s):

Sandy Loam ◽

Extraction Methods ◽

Available P ◽

Molar Ratio ◽

P Availability ◽

Triple Superphosphate ◽

Experimental Conditions ◽

Reactive Phosphate ◽

Exchange Resins ◽

P Sources

Despite the large number of studies addressing the quantification of phosphorus (P) availability by different extraction methods, many questions remain unanswered. The aim of this paper was to compare the effectiveness of the extractors Mehlich-1, Anionic Resin (AR) and Mixed Resin (MR), to determine the availability of P under different experimental conditions. The laboratory study was arranged in randomized blocks in a [(3 x 3 x 2) + 3] x 4 factorial design, with four replications, testing the response of three soils with different texture: a very clayey Red Latosol (LV), a sandy clay loam Red Yellow Latosol (LVA), and a sandy loam Yellow Latosol (LA), to three sources (triple superphosphate, reactive phosphate rock from Gafsa-Tunisia; and natural phosphate from Araxá-Minas Gerais) at two P rates (75 and 150 mg dm-3), plus three control treatments (each soil without P application) after four contact periods (15, 30, 60, and 120 days) of the P sources with soil. The soil acidity of LV and LVA was adjusted by raising base saturation to 60 % with the application of CaCO3 and MgCO3 at a 4:1 molar ratio (LA required no correction). These samples were maintained at field moisture capacity for 30 days. After the contact periods, the samples were collected to quantify the available P concentrations by the three extractants. In general, all three indicated that the available P-content in soils was reduced after longer contact periods with the P sources. Of the three sources, this reduction was most pronounced for triple superphosphate, intermediate for reactive phosphate, while Araxá phosphate was least sensitive to the effect of time. It was observed that AR extracted lower P levels from all three soils when the sources were phosphate rocks, while MR extracted values close to Mehlich-1 in LV (clay) and LVA (medium texture) for reactive phosphate. For Araxá phosphate, much higher P values were determined by Mehlich-1 than by the resins, because of the acidity of the extractor. For triple superphosphate, both resins extracted higher P levels than Mehlich-1, due to the consumption of this extractor, particularly when used for LV and LVA.

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Utilization of Non-Living Microalgae Biomass from Two Different Strains for the Adsorptive Removal of Diclofenac from Water

Water ◽

10.3390/w10101401 ◽

2018 ◽

Vol 10 (10) ◽

pp. 1401 ◽

Cited By ~ 11

Author(s):

Ricardo Coimbra ◽

Carla Escapa ◽

Nadyr Vázquez ◽

Guillermo Noriega-Hevia ◽

Marta Otero

Keyword(s):

Activated Carbon ◽

Experimental Conditions ◽

Biomass Waste ◽

Adsorptive Removal ◽

Microalgae Biomass ◽

Langmuir Isotherm Model ◽

Pseudo Second Order ◽

Equilibrium Concentrations ◽

Different Strains ◽

Synechocystis Sp

In the present work, the adsorptive removal of diclofenac from water by biosorption onto non-living microalgae biomass was assessed. Kinetic and equilibrium experiments were carried out using biomass of two different microalgae strains, namely Synechocystis sp. and Scenedesmus sp. Also, for comparison purposes, a commercial activated carbon was used under identical experimental conditions. The kinetics of the diclofenac adsorption fitted the pseudo-second order equation, and the corresponding kinetic constants indicating that adsorption was faster onto microalgae biomass than onto the activated carbon. Regarding the equilibrium results, which mostly fitted the Langmuir isotherm model, these pointed to significant differences between the adsorbent materials. The Langmuir maximum capacity (Qmax) of the activated carbon (232 mg∙g−1) was higher than that of Scenedesmus sp. (28 mg∙g−1) and of Synechocystis sp. (20 mg∙g−1). In any case, the Qmax values determined here were within the values published in the recent scientific literature on the utilization of different adsorbents for the removal of diclofenac from water. Still, Synechocystis sp. showed the largest KL fitted values, which points to the affinity of this strain for diclofenac at relative low equilibrium concentrations in solution. Overall, the results obtained point to the possible utilization of microalgae biomass waste in the treatment of water, namely for the adsorption of pharmaceuticals.

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