Pseudo-second Order Mechanism Research Articles

Fabrication of Novel Agrowaste (Banana and Potato Peels)-Based Biochar/TiO2 Nanocomposite for Adsorption of Cr(VI), Statistical Optimization via RSM Approach.

In this research work, a simple, efficient, and eco-friendly procedure for the biosorption of Cr(VI) ions was studied. A detailed comparative study was performed to check the adsorption efficiency of agrowaste (banana and potato peels)-based adsorbents. Firstly, mixed biosorbent was washed, dried and ground into powder, secondly, biosorbent was pyrolyzed into biochar and thirdly TiO2 nanocomposite (TiO2 NC) biosorbent was made by sonicating using prepared biochar and TiO2 NPs. Titanium dioxide nanoparticles (TiO2 NPs) were synthesized by a green method using Psidium guajava leaf extract. The synthesized adsorbents were characterized by SEM, EDX FT-IR, XRD and UV-visible analysis. The effect of four different factors, i.e., pH of the synthetic metallic solution, time, concentration and adsorbent dosage was studied. The optimum conditions were time (120 min), pH (3), concentration (10 ppm) and adsorbent dosage (1.0 g). The kinetic modeling showed that the adsorption of Cr(VI) ion follows a pseudo second-order mechanism and the Langmuir isotherm model was found to fit better for this study. Response surface methodology (RSM)-based optimized parameters provided optimal parameter sets that better represent the adsorption rate models. The uptake capacity of Cr(VI) from aqueous solution was found to be biomass (76.49 mg/L) ˂ biochar (86.51 mg/L) ˂ TiO2 NC (92.89 mg/L). It can be suggested that the produced TiO2 NC could possibly be an efficient biosorbent for the removal of Cr(IV).

Carbon Double Coated Fe3O4@C@C Nanoparticles: Morphology Features, Magnetic Properties, Dye Adsorption.

This work is devoted to the study of magnetic Fe3O4 nanoparticles doubly coated with carbon. First, Fe3O4@C nanoparticles were synthesized by thermal decomposition. Then these synthesized nanoparticles, 20–30 nm in size were processed in a solution of glucose at 200 °C during 12 h. The morphology and features of the magnetic properties of the obtained hybrid nanoparticles were characterized by transmission electron microscopy, differential thermo-gravimetric analysis, vibrating sample magnetometer, magnetic circular dichroism and Mössbauer spectroscopy. It was shown that the magnetic core of Fe3O4@C nanoparticles was nano-crystalline, corresponding to the Fe3O4 phase. The Fe3O4@C@C nanoparticles presumably contain Fe3O4 phase (80%) with admixture of maghemite (20%), the thickness of the carbon shell in the first case was of about 2–4 nm. The formation of very large nanoparticle conglomerates with a linear size up to 300 nm and of the same regular shape is a remarkable peculiarity of the Fe3O4@C@C nanoparticles. Adsorption of organic dyes from water by the studied nanoparticles was also studied. The best candidates for the removal of dyes were Fe3O4@C@C nanoparticles. The kinetic data showed that the adsorption processes were associated with the pseudo-second order mechanism for cationic dye methylene blue (MB) and anionic dye Congo red (CR). The equilibrium data were more consistent with the Langmuir isotherm and were perfectly described by the Langmuir–Freundlich model.

Prosopis Juliflora (Kikar) pods as adsorbent for removal of Cd(II) ions from aqueous streams

Cadmium Cd(II) is a heavy metal, the presence of which in an aqueous ecosystem is detrimental to human beings, animals and vegetation due to its mobile, toxic and non-biodegradable nature. Different treatment techniques like neutralization, coagulation and flocculation, oxidation, ion exchange, ozonation, membrane separation and disinfection have been employed, but eco-friendly techniques involving adsorption on natural and bio-degradable adsorbents is the most favourable one as it is the least costly, flexible in design and possesses large removal efficiencies. The present work is based on the adsorptive removal of Cd(II) ions from wastewater streams employing biosorbent prepared from Prosopis Juliflora (kikar) pods. To determine the parametric sensitivity of the adsorptive removal, batch experiments have been carried out by varying the dosage of the adsorbent, initial Cd(II) concentration, pH and the time of contact. The chemical/microstructural composition of adsorbent prepared from raw and carbonized kikar pods has been examined by its proximate analysis, SEM and FTIR. The carbonized kikar pods can act as an economical, eco-friendly and practical adsorbent for Cd(II) from wastewater streams as they displayed a maximum removal efficiency of 82% and a maximum metal uptake capacity of 16 mg g−1 of biosorbent. Further, to comprehend the kinetic data for the adsorptive removal, a pseudo-second order mechanism has been proposed.

Amino-Functionalized Fe3O4@SiO2 Core-Shell Magnetic Nanoparticles for Dye Adsorption.

Fe3O4@SiO2 core-shell nanoparticles (NPs) were synthesized with the co-precipitation method and functionalized with NH2 amino-groups. The nanoparticles were characterized by X-ray, FT-IR spectroscopy, transmission electron microscopy, selected area electron diffraction, and vibrating sample magnetometry. The magnetic core of all the nanoparticles was shown to be nanocrystalline with the crystal parameters corresponding only to the Fe3O4 phase covered with a homogeneous amorphous silica (SiO2) shell of about 6 nm in thickness. The FT-IR spectra confirmed the appearance of chemical bonds at amino functionalization. The magnetic measurements revealed unusually high saturation magnetization of the initial Fe3O4 nanoparticles, which was presumably associated with the deviations in the Fe ion distribution between the tetrahedral and octahedral positions in the nanocrystals as compared to the bulk stoichiometric magnetite. The fluorescent spectrum of eosin Y-doped NPs dispersed in water solution was obtained and a red shift and line broadening (in comparison with the dye molecules being free in water) were revealed and explained. Most attention was paid to the adsorption properties of the nanoparticles with respect to three dyes: methylene blue, Congo red, and eosin Y. The kinetic data showed that the adsorption processes were associated with the pseudo-second order mechanism for all three dyes. The equilibrium data were more compatible with the Langmuir isotherm and the maximum adsorption capacity was reached for Congo red.

Methylene blue adsorption by activated carbon, nickel alginate/activated carbon aerogel, and nickel alginate/graphene oxide aerogel: a comparison study

Three adsorbents, trichosanthes kirilowii maxim shell activated carbon (TKAC), nickel alginate/activated carbon (NA/AC) aerogel and nickel alginate/graphene oxide (NA/GO) aerogel were prepared in the present study. The three-dimensional network structure of the NA/AC aerogel and NA/GO aerogel was found to effectively control the dispersion state of TKAC and GO. The adsorption behavior was systematically investigated in terms of adsorption temperature and time, initial adsorbate pH and concentration, as well as the dose of adsorbents. The methylene blue (MB) adsorption process of TKAC was in accordance with the Langmuir isotherm model and followed a pseudo-second order mechanism. The adsorbing capacity of TKAC was 505.050mg/g at 303K while the BET surface area was 349.400m2/g. Thermodynamic analysis demonstrated the spontaneous and endothermic properties of the entire adsorption process. The MB adsorption of the NA/AC aerogel satisfied the Langmuir isotherm and Freundlich isotherm models. Moreover, the MB adsorption on the NA/AC aerogel followed a pseudo-second order mechanism. The adsorbing capacity of the NA/AC aerogel was observed to be 465.120mg/g at 303K while the BET surface area was 100.690m2/g. Thermodynamic investigation demonstrated a spontaneous and exothermic nature of the overall adsorption process. The MB adsorption of the NA/GO aerogel aligned with the Langmuir isotherm model and followed pseudo-second order mechanism. The adsorbing capacity of NA/GO aerogel was found to be 537.630mg/g at 303K, while the BET surface area was 5.050m2/g. Furthermore, thermodynamic studies exhibited spontaneous and exothermic properties of the entire adsorption process.

Adsorption of Copper (II) from Aqueous Solution by Using Carbonized Peanut Hull: Determination of the Equilibrium, Kinetic and Thermodynamic Parameters

In this study, the effect of temperature, pH, initial metal concentration and adsorbent dosage on Cu(II) adsorption onto carbonized peanut hull (PHC) was investigated. Activated carbon was prepared from peanut hull. It was produced by carbonization in carbon diokside atmosphere at 500 °C for 1.0 h. The maximum Cu (II) adsorption capacity was obtained as 168.16 mg/g for 500 mg/L initial Cu (II) at pH = 4.0 and 60 °C. The Freundlich and Langmuir adsorption models were used for the mathematical description of the adsorption equilibrium. The best interpretation for the experimental data was given by the Freundlich isotherm and the maximum adsorption capacity was obtained. Batch adsorption models, based on the assumption of the pseudo-first and pseudo-second order mechanism, were applied to examine the kinetics of the adsorption. Kinetic data fitted the pseudo-second kinetic order model. Thermodynamic functions, the change of free energy (Go), enthalpy (Ho) and entropy (So) of copper adsorption on PHC were calculated as -23.21 kjmol-1 (at 60 oC), 15.94 kjmol-1 and 117.59 kjmol-1 K-1, respectively, indicating the spontaneous, endothermic and the increased randomness nature of Cu2+ adsorption. The results show that adsorption of Cu (II) on PHC is an.

Synthesis and characterisation of zinc hydroxides nitrates–sodium dodecyl sulphate fluazinam nano hosts for release properties

A new nano host-fungicide, namely zinc hydroxide nitrate–sodium dodecyl sulphate–fluazinam (ZHN–SDS–FZ) was successfully synthesised using an ion exchange method. The intercalation of fluazinam (FZ) in the interlayer gallery of ZHN–SDS was confirmed by PXRD pattern with the basal spacing of 32.7 A. The FTIR confirmed that FZ exist in the interlayer gallery. The elemental analysis also supported the presence of FZ in the interlayer ZHN–SDS where the percentages of nitrogen, which contributed by FZ was 65.6%. Meanwhile, the percentages of Zn in the nano host-fungicides was estimated to be 11.5%. Furthermore, TGA/DTG pattern showed that the nano host-fungicide ZHN–SDS–FZ has better thermal stability compared to pure FZ. The intercalation of FZ leads to the change of morphology, surface area and also the porosity. The classification of porosity of ZHN–SDS is mesoporous, meanwhile ZHN–SDS–FZ is non-porous. The BET-BJH surface area shows that ZHN–SDS and ZHN–SDS–FZ is of Type IV and Type III respectively. The controlled release of FZ from the ZHN–SDS–FZ nano host showed that phosphate and carbonate solutions yield the higher percentages of release compared to chloride solutions. The controlled release of FZ was found to be governed by a pseudo-second order mechanism for all medium. In this research, FZ can act as a good guest anion to be intercalated in the interlayer ZHN–SDS to be further used in agricultural sector due to the slowest release of FZ in the phosphate, carbonate and chloride solutions as a release medium.

Adsorption of 3-Aminopyridine (3AP) from aqueous solution using sugarcane bagasse activated carbon (SBAC)

Abstract Adsorption of 3-Aminopyridine (3AP) from simulated effluent using sugarcane bagasse activated carbon (SBAC) was studied based on batch and continuous operations. Characterization of synthesized SBAC was performed initially using BET and SEM analysis. Different batch experiments were performed to understand the effect of operating parameters such as initial concentration, pH, SBAC dose, time and temperature to understand the effect on the extent of adsorption. The maximum adsorption capacity for batch adsorption was established as 54.4 mg/g whereas the maximum extent of removal was 97.6 % under optimized conditions. The observed data at equilibrium was found to be best fitted to Freundlich and Langmuir adsorption isotherms. Kinetic study revealed that pseudo-second order mechanism prevailed. Desorption of 3AP using ethanol showed good reuse efficacy for five cycles. Column adsorption experiments were also performed under varying SBAC bed height, concentration of 3AP and volumetric flow rate of 3AP solution to determine the breakthrough parameters. The fitting of the Yoon–Nelson and Thomas adsorption models to the obtained breakthrough data was studied and found to be satisfactory. Maximum adsorption capacity of SBAC for adsorption of 3AP in continuous operation was established as 65.6 mg/g. The obtained results demonstrated very good performance of SBAC for effective removal of 3AP in both batch and column operations.

INFLUÊNCIA DO FÓSFORO INORGÂNICO E VALOR DE PH NA REMOÇÃO DE FORMULAÇÃO À BASE DE GLIFOSATO EM AMBIENTE AQUOSO POR ADSORÇÃO

A degradação dos recursos hídricos provocada pelas atividades antrópicas tem alterado as características físico-químicas de águas superficiais, o que, por sua vez, interfere na mobilidade de compostos capazes de se fixarem em sedimentos. Dessa forma, o presente trabalho avaliou a influência da concentração de fósforo edo valor de potencial hidrogeniônico (pH) na cinética e na capacidade de adsorção do glifosato (solução comercial) em argila expandida, utilizando sistema constituído de coluna de leito fixo operado em regime hidrodinâmico fechado com circulação contínua do adsorbato. Utilizou-se o modelo de planejamento experimental para três concentrações de fósforo, 0,8, 8 e 16 mg L-1 e três valores de pH, 4, 7 e 10, totalizando nove ensaios. Verificou-se que o aumento do pH e da concentração de fósforo levou à diminuição na velocidade de adsorção, enquanto o mecanismo cinético foi afetado somente pela concentração de fósforo, prevalecendo o mecanismo de pseudossegunda ordem nas concentrações de 0,8 e de 8 mg L-1 eo intrapartícula para a maior concentração. A capacidade de adsorção foi afetada por ambos os parâmetros. A cada aumento de 0,16 no valor de pH e 0,22 mg L-1 na concentração de fósforo, a massa adsorvida de glifosato diminuiu em 0,000385 mg g-1 e 0,000205 mg g-1, respectivamente. Dessa forma, concluiu-se que o aumento do pH e da concentração de fósforo diminuiu tanto a capacidade quanto a velocidadede adsorção do glifosato (formulação comercial), enquanto o mecanismo cinético somente foi alterado para a concentração de fósforo de 16 mgL-1.

Adsorption kinetics models in clay systems. The critical analysis of pseudo-second order mechanism

The research topics involving adsorption kinetics of chemical substances on clays and related materials include hundreds of papers over the last decades. In many of them, it is concluded that the adsorption is governed by the so-called pseudo-second order (PSO) mechanism. These conclusions mostly come from regression analysis of adsorption data using the simplified linearized form of the model. The in-depth analysis presented in this paper shows the unsuitability of the linearized function to evaluate the goodness of the PSO model for adsorption data. This paper presents more accurate ways of testing adsorption data using original non-linear models. The results have a significant impact on the reassessment of the interpretations published in earlier studies aimed at adsorption kinetics for the systems based on clays, as well as other adsorbents and materials.

Adsorption of enhanced oil recovery polymer, schizophyllan, over carbonate minerals

Schizophyllan is a natural polysaccharide that has shown great potential as enhanced oil recovery (EOR) polymer for high-temperature, high-salinity reservoirs. Nevertheless, the adsorption behavior of schizophyllan over carbonate minerals remains ambiguous element towards its EOR applications. Here, we investigate the adsorption of schizophyllan on different carbonate minerals. The effect of mineral type, salinity, and background ions on adsorption is analyzed. Our results indicate the adsorption capacity is higher on calcite and dolomite compared to silica and kaolin and the adsorption capacity decreases with salinity. Moreover, the adsorption kinetics follows pseudo-second order mechanism regardless of the mineral type. Adsorption over calcite is diminished in presence of water structure making ions and enhanced in presence of structure breaking ion and in presence of urea. Gel permeation chromatography results reveal the preferential adsorption of longer chains. The adsorption over carbonate minerals proceed via complex formation between polymer molecule and mineral surface.

Molecularly imprinted cryogel beads for cholesterol removal from milk samples

This study presents the development of a cholesterol-selective adsorbent that can be easily produced for the highly efficient removal of cholesterol from milk. A fundamental affinity separation technology which was combined with the specific recognition property of molecular imprinting with a high flow rate and the resulting cryogel was used to separate cholesterol separation from milk samples. The proposed material offers a reasonable pore size and structure, high surface area, and mechanical and chemical stability. To separation the cholesterol from milk, poly(2-hyroxyethyl methacrylate-N-methacryloyl-l-tryptophan methylester) cryogel beads were prepared using a functional monomer that allowed the formation of cholesterol-selective binding sites and enhanced the selective removal of cholesterol from milk. Characterization studies of the cholesterol-imprinted cryogel beads (CHO-MIPs) were carried out by attenuated total reflectance-Fourier transform infrared spectroscopy, scanning electron microscopy, elemental analysis, water-uptake tests and surface area measurements. The interactions between CHO-MIP and cholesterol were investigated and the factors affecting the adsorption of cholesterol were determined to find optimum conditions. Reusability as a measure of the continuity of the prepared CHO-MIPs was also investigated. The selectivity of the CHO-MIP beads was determined by using competing molecules (estradiol and progesterone), which are cholesterol analogues. The experimental data showed that the specific areas of the CHO-MIP and non-imprinted (NIP) cryogel beads were 17.6 and 14.7 m2/g, respectively. The CHO-MIP cryogel beads were 4.77 and 2.76 fold more selective for cholesterol compared to estradiol and progesterone respectively. The cholesterol adsorption capacity of the CHO-MIP beads was 288.72 mg/g when the cholesterol concentration in solution was 3.0 mg/mL. After eight adsorption-desorption cycles, the adsorption capacity of the CHO-MIP beads decreased by 9.21 %. The Langmuir-Freundlich isotherm model was well fitted as compare to Langmuir and Freundlich isotherms. The obtained kinetics data showed that a pseudo-second order mechanism was predominant for the CHO-MIP cryogel bead adsorption.

Adsorption of Acidol Red 2BE-NW Dye from Aqueous Solutions on Carboxymethyl Cellulose/Organo-Bentonite Composite: Characterization, Kinetic and Thermodynamic Studies

The combination of biopolymers and clay minerals to form new composite materials offers new horizons and promises to reveal a great potential in the efficient removal of hazardous pollutants from wastewater. The adsorptive removal of Acidol Red 2BE-NW (AR42) with carboxymethyl cellulose/organo-bentonite (CMC/OBent) composite is investigated. The composite is characterized by means of Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), thermal gravimetric (TG) analysis, Brunauer–Emmett–Teller (BET) specific surface area and Barret–Johner–Halenda (BJH) pore size distribution analyses. The adsorption of AR42 anionic dye from aqueous solution onto the CMC/OBent composites is assessed by varying parameters such as the mass ratio of CMC to organo-bentonite, the pH value of the dye solution, the temperature, the contact time and the initial dye concentration. The organic modification of bentonite stimulates the intercalation of CMC molecules into the interlayer space of organo-bentonite. An intermolecular as well as an intramolecular linkage (interaction) among CMC molecules and organo-bentonite platelets is observed as evidenced by the FT-IR analysis. Dye equilibrium uptake is reached within 60 min, yielding a maximum dye sorption of 91.14% at a pH of 5.2, with an adsorption capacity of 29.16 mg/g at 25 °C. Adsorption kinetics of AR42 onto the CMC/OBent composite is best described by a pseudo second-order mechanism, while its adsorption isotherm fits well into the Freundlich equation. The potential for AR42 dye removal with CMC/OBent composite is discussed.

Adsorption of light green and brilliant yellow anionic dyes using amino functionalized magnetic silica (Fe3O4@SiO2@NH2) nanocomposite

Fe3O4@SiO2@NH2 nanocomposite was prepared for highly effective adsorption of two anionic dyes one of which is triarylmethane dye (light green, LG) and the other is azo dye (brilliant yellow, BY). The characterization results demonstrated that superparamagnetic Fe3O4 nanoparticles were covered with silica and functionalized with amino groups successfully without losing magnetic character. The effects of adsorbent dosage, contact time, pH, temperature, and dye molecular structure on the adsorption were investigated. Acidic pH was better for both LG and BY, on the other hand, alkaline pH was favorable to some extent for LG in comparison with BY due to the contribution of stacking effect in addition to electrostatic attraction. Kinetic data demonstrated that the driving force for adsorption process could be explained by pseudo-second order mechanism in both systems. The equilibrium data were more compatible with Langmuir isotherm than those of Freundlich isotherm and the maximum adsorption capacities of Fe3O4@SiO2@NH2 calculated from Langmuir isotherm model for LG and BY at 30 °C and natural pH of the solution were 40.2 and 35.5 mg g−1. Thermodynamic calculations related to temperature dependence demonstrated that the adsorption process was spontaneous and exothermic.

Investigation on effects of ion exchangers structure and functional groups on the Re(VII) ions adsorption behavior from aqueous solution

ABSTRACTAlteration adsorption properties of Re(VII) on two resins with different functional groups and structure, weak base/macroporous and strong base/gel type, Purolite A170 (A170) and Dowex 21K (21K) respectively, were investigated experimentally and interpreted by isotherm, kinetic and thermodynamic modeling. Following the comparison of coefficient of determination values, the Freundlich and D-R isotherm models were found to be more suitable for description of investigated systems (R2 > 0.99). The Langmuir isotherm capacities (qm) were indicated that the perrhenate ions (ReO4−) adsorption is higher for weak base/macroporous type resin rather than the other at pH 3 in the presence of 50–250 mg L−1 Re (166.67 and 142.86 mg g−1, respectively). Also, the results from EDX studies corroborated this phenomenon. The adsorption reaction on both adsorbents was found to be chemically with mean free energy, E, as 12.18 and 13.62 kJ mol−1 for A170 and 21K, respectively. Kinetics of adsorption was studied by fitting the data into different mechanisms, among which the pseudo-second order mechanism was found successful for both used resins, but in case of 21K, the rate of perrhenate ions uptake was more rapid than A170. That is possibly attributed to the presence of strong base (quaternary amine) in functional groups. ΔG values obtained were all negative for both resins indicating a spontaneous adsorption process. The positive values of both ΔH (3.34 kJ mol−1) and ΔS (27.31 J mol−1 K−1) obtained suggest an endothermic reaction and in increase in randomness at the solid–liquid interface during the adsorption onto the A170 resin while for 21K, the negative changes in enthalpy and entropy provide an indication that the process is endothermic as well as it follows associative mechanism.

Boron doped graphene oxide with enhanced photocatalytic activity for organic pollutants

In present study, boron doped reduced graphene oxide (BR-GO) is synthesized by reducing graphene oxide (GO) in the presence of boric acid, and employed as a photocatalyst for the degradation of organic pollutants methyl orange (MO) and methylene blue (MB). GO and BR-GO are systematically characterized by X-ray diffraction, Raman spectroscopy, high resolution transmission electron microscopy, X-ray photoelectron spectroscopy and UV–vis spectroscopy. The modifications in the structure of GO are confirmed. The BR-GO has sheet structure with various graphene islands and disordered regions. The electrical conductivity has been measured using two-probe method. The conductance is explained by two-dimensional variable range hopping model. The photocatalytic activity of GO is enhanced on doping with boron due to increase in the density of states value near Fermi level. The adsorption mechanism and kinetic studies for the degradation of MB and MO dyes suggest that the photocatalytic degradation follows a pseudo-second order mechanism.

Uranium sorption from aqueous solutions using polyacrylamide-based chelating sorbents

ABSTRACTThis article introduces an investigation on the sorption power of two polyacrylamide-based chelating sorbents for uranium ion removal from aqueous solutions. The studied sorption parameters involved pH, contact time, initial uranium concentration, and polymer dosage. The results revealed that a maximum uptake percentage of 65.3 mg/g and 20.1 mg/g for polymers I and II, respectively, could be obtained at pH 4 with 120 min shaking time. Based on isotherm, kinetic, and thermodynamic studies, the sorption process of uranium on the chelating polymers is said to follow Langmuir isotherm model with pseudo second-order mechanism and exothermic nature.

Removal of pyrene and benzo(a)pyrene micropollutant from water via adsorption by green synthesized iron oxide nanoparticles

Polycyclic aromatic hydrocarbons (PAHs) in water are classified as organic micropollutants, which are carcinogenic even in very low concentration (ppb). In this study the green synthesized iron oxide nanoparticles (IONPs) were green synthesized at room temperature by using pomegranate peel extract. The green synthesized IONPs were used for adsorbing benzo(a)pyrene and pyrene (PAHs) from water. Factors affecting the adsorption were investigated. These factors are: nanoparticles dose, pH, temperature, and initial concentration of PAHs. The overall results showed that the maximum adsorption capacities of IONPs towards pyrene and benzo(a)pyrene were 2.8 and 0.029 mg g−1, respectively. The thermodynamic study indicated an exothermic adsorption process of pyrene and benzo(a)pyrene. The kinetic and isotherm studies were carried out. The obtained data revealed that the adsorption process follows a pseudo-second order mechanism and obeys Langmuir isotherm model. In addition, the IONPs proved to be a potential candidate for the adsorption of pyrene and benzo(a)pyrene even after five cycles of use and regeneration. The investigation was extended using semi-pilot plant to remove the studied PAHs from artificially contaminated water. The results showed that the IONPs was capable to remove the pyrene and benzo (a) pyrene at the rate of 98.5 and 99%, respectively. It also can be used as disinfectant.

Sorption Characteristics of Iron, Fluoride and Phosphate from Wastewater of Phosphate Fertilizer Plant using Natural Sodium Bentonite

The phosphate fertilizer industry generates a highly hazardous and acidic wastewater. Effluent samples were obtained from wastewater streams produced in Abu Zaabal for Fertilizer and Chemicals Company (AZFC). The present study reports a process for iron, fluoride, and phosphate sorption from the wastewater samples using natural sodium bentonite. Accordingly, a series of batch experiments were performed to study the influence of various experimental parameters, such as solution shaking time, solution pH, and clay amount of addition, temperature, and mechanical stirring speed. The obtained results clear that, the sorption preferred conditions were; shaking time of 60 mts, solution pH of 4, room temperature, and bentonite amount of addition of 1.0 g/L. Based on kinetic and thermodynamic studies, the sorption process of iron, fluoride and phosphate on Na-bentonite is said to follow pseudo-second order mechanism and endothermic nature.

Kinetic and thermodynamic study of adsorptive removal of sodium dodecyl benzene sulfonate using adsorbent based on thermo-chemical activation of coconut shell

Adsorptive separation of Sodium dodecyl benzene sulfonate (SDBS) using thermo-chemically and chemically activated coconut shell based adsorbent as well as using waste graphite powder has been investigated. The dependency of the extent of SDBS removal on pH, concentration, adsorbent dose and temperature has been demonstrated. Under optimized conditions, 92.84%, 39.41% and 34.23% SDBS could be removed in 3h using Phosphoric Acid Activated Coconut Shell-I (PAACS-I), Phosphoric Acid Activated Coconut Shell-II (PAACS-II) and graphite powder respectively. Adsorption kinetics was established to follow pseudo-second order mechanism and isotherm data fitted well with the Langmuir isotherm. Maximum adsorption capacity was estimated to be 28.57mg/g under optimized conditions of pH as 2, adsorbent dose of 3g/L and temperature of 293K. It was also established that adsorption was spontaneous and exothermic. Appreciable activity till 5th reuse cycle confirmed promising nature of the adsorbent.