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Showing papers in "Journal of The Taiwan Institute of Chemical Engineers in 2017"


Journal ArticleDOI
TL;DR: A review of common kinetic models for liquid adsorption can be found in this paper, where the authors discuss their origins, features, modified versions, applicability, and applicability with regard to liquid adaption modeling for both batch and dynamic systems.
Abstract: The past decade has seen a boom in environmental adsorption studies on the adsorptive removal of pollutants from the aqueous phase. A large majority of works treat kinetic modeling as a mere routine to describe the macroscopic trend of adsorptive uptake by using common models, often without careful appraisal of the characteristics and validity of the models. This review compiles common kinetic models and discusses their origins, features, modified versions (if any), and applicability with regard to liquid adsorption modeling for both batch adsorption and dynamic adsorption systems. Indiscriminate applications, ambiguities, and controversies are highlighted and clarified. The appropriateness of linear regression for correlating kinetic data is discussed. This review concludes with a note on the current scenario and the future of kinetics modeling of liquid adsorption.

676 citations


Journal ArticleDOI
TL;DR: In this article, a review of strong metal-support interactions (SMSI) is presented, which are responsible for the catalytic activity, selectivity and stability of various reaction systems, such as heterogeneous catalysis and electrocatalysis.
Abstract: Interactions between metals and supports are of fundamental interest in heterogeneous catalysis. The electronic, geometric and bifunctional effects originating from Strong Metal-Support Interactions (SMSI) that are responsible for the catalyst's activity, selectivity, and stability are key factors that determine performance. Research into SMSI is fast-growing with many revolutionary systems being developed to enhance our understanding of its nature and effects. This review starts with a brief overview of heterogeneous catalysis and SMSI; then three major mechanisms involving electronic, geometric and bifunctional effects are summarized to introduce the fundamental concepts, recent progress and disagreement remained. Subsequently, advanced analytical techniques are introduced as contemporary approaches to the investigation and understanding of SMSI. In addition, the effects of SMSI on the catalytic activity, selectivity and stability of various reaction systems, such as heterogeneous catalysis and electrocatalysis are examined. Additionally, a brief review of various protocols used for the manipulation of interactions between metals and supports is given. Lastly, the future of SMSI with respect to further developments and ongoing challenging issues is addressed.

221 citations


Journal ArticleDOI
TL;DR: In this article, the application of different type of carbon-based nanomaterials in water and wastewater treatment is reviewed, and the role of carbon nanomorphs role in adsorption, disinfection and membrane separation mechanisms is discussed.
Abstract: Advanced science and technology based on carbon-based nanomaterials is experiencing a rapid rate of change in the performance capabilities to substitute or serve as alternative approaches for the existing technologies. One of the major environmental concerns is the water pollution by the heavy metals. Heavy metals in water are the main preoccupation for many years because of the toxicity towards aquatic-life, human beings and also the environment. In the context of water and wastewater treatment, significant numbers of breakthroughs have been achieved to drive accelerated change for ceaseless capability improvements. In this contribution, the unique features of promising carbon-based nanomaterials that have generated tremendous interest among the material researchers are described along with their potential applications in water and wastewater treatment. Carbon-based nanomaterials stand out to be one of the highly efficient nanomaterials due to it is a vast availability and lower production cost compared to other nanomaterials. This paper critically reviewed the application of different type of carbon-based nanomaterials in water and wastewater treatment. The carbon nanomaterials role in adsorption, disinfection and membrane separation mechanisms that enable the applications are discussed. Advantages and limitations as well as barriers and research needs are highlighted. Challenges include technical hurdles, high cost, and environmental and health risk.

202 citations


Journal ArticleDOI
TL;DR: In this paper, a mesoporous high-surface-area zeolite-activated carbon (Z-AC) composite was prepared by chemically facilitated NaOH activation and hydrothermal treatment with oil palm ash as substrate.
Abstract: A mesoporous high-surface-area zeolite–activated carbon (Z–AC) composite was prepared by chemically facilitated NaOH activation and hydrothermal treatment with oil palm ash as substrate. The prepared Z–AC composite was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, BET surface area and pore structural analysis, and scanning electron microscopy. The adsorption performance of Z–AC for methylene blue (MB) removal was examined using a batch method. The effects of initial dye concentration (25–400 mg/L), temperature (30 °C–50 °C), and pH (3–13) on the adsorption of MB on Z–AC were studied. Pseudo-second-order kinetics was found to describe the adsorption process better than pseudo-first-order kinetics. Freundlich and Langmuir isotherms applied on the adsorption data reveal that data best fitted Freundlich model. The maximum adsorption capacity values of the Z–AC composite for MB were 143.47, 199.6, and 285.71 mg/g at 30, 40, and 50 °C, respectively. These results show that the Z–AC composite could provide basis for more low-cost composites to be used as adsorbents for dye removal.

167 citations


Journal ArticleDOI
TL;DR: In this paper, karanj (Pongamia pinnata ) fruit hulls were used as a precursor to prepare low-cost activated carbon with a large surface area through KOH activation.
Abstract: In this study, karanj ( Pongamia pinnata ) fruit hulls were used as a precursor to prepare low-cost activated carbon with a large surface area through KOH activation. The prepared activated carbon (KFHAC) was characterized through pore structural analysis, scanning electron microscopy, and Fourier transform infrared spectroscopy. KFHAC presents a BET surface area of 828.30 m 2 /g, a micropore volume of 0.36 cm 3 /g, and an average pore size of 19.92 A The adsorption performance of KFHAC was evaluated using methylene blue (MB) as the model adsorbate. Adsorption experiments indicated that the pseudo-second-order kinetic and Langmuir adsorption isotherm models can accurately describe the adsorption process. The maximum adsorption capacities ( q m ) of MB were 154.8, 203.4, and 239.4 mg/g at 30 °C, 40 °C, and 50 °C, respectively. This study indicates that karanj fruit hull is a promising precursor for the production of low-cost and efficient activated carbon with a large surface area.

152 citations


Journal ArticleDOI
TL;DR: In this paper, a colloidal suspension consisting of Cu nanoparticles and engine oil has been made by a one-step method known as Electrical Explosion of Wire (E.E.W).
Abstract: In this study, a colloidal suspension consists of Cu nanoparticles and engine oil has been made by a one- step method known as Electrical Explosion of Wire (E.E.W) in three different weight concentrations of 0.2%, 0.5% and 1%. After studying physical properties of the applied nanofluids via high resolution transmission electron microscopy and measuring zeta potential for the stability analysis, thermo-physical properties such as thermal conductivity and viscosity, have been experimentally studied. Measured data of thermal conductivity and viscosity of applied nanofluids have been compared to the predicted ones through the proposed correlations for thermal conductivity and viscosity of oil based nanofluids and acceptable agreements between the two have been achieved. The range of thermal conductivity of higher weight concentration was measured to be from 0.153 to 0.17 (W/m. K) in the temperature range from 40 C to 100 C, while pure engine oil exhibits a decreasing trend in contradictory. Secondly, viscosity variations through capturing Newtonian or non- Newtonian behavior of utilized nanofluids has been investigated. The viscosity range for higher weight concentration nanofluid was observed from 235 cP to 35 cP in the applied temperature range. Finally, thermal conductivity and viscosity enhancements of 49% and 37% were observed for 1% weight fraction of utilized nanofluids.

148 citations


Journal ArticleDOI
TL;DR: In this article, the effects of hybrid nanoparticles on the melting process of a nano-enhanced phase-change material (NEPCM) inside an enclosure were investigated and it was found that increasing the values of the nanoparticles volume fraction, viscosity and conductivity parameters leads to significant variations in the solid-liquid interface for large values of Fourier number.
Abstract: The present study deals with the effects of hybrid nanoparticles on the melting process of a nano-enhanced phase-change material (NEPCM) inside an enclosure. The bottom side of the cavity is isothermal at a hot temperature while the top wall is isothermal at a cold temperature and the left and right walls are insulated. The governing partial differential equations are first non-dimensional form and then solved using the Galerkin finite element method. Some of the dimensionless parameters are kept constant such as the Prandtl number, the Rayleigh number, the Stefan number and the ratio between the thermal diffusivity of the solid and liquid phases while the volume fraction of nanoparticles, the conductivity and viscosity parameters, and the Fourier number are altered. It is found out that increasing the values of the nanoparticles volume fraction, viscosity and conductivity parameters leads to significant variations in the solid-liquid interface for large values of Fourier number. Moreover, increasing the conductivity parameter and decreasing the viscosity parameter at the same time can cause an augmentation in the liquid fraction.

142 citations


Journal ArticleDOI
TL;DR: In this article, the effects of different key parameters such as Ra number (10 3 -10 6 ), aspect ratio of the channel (0.2 -0.6), nano-particle volume fraction of (0 −0.05), position and height of the hot obstacle and nanoparticle diameter (20 −80 nm) on the heat transfer inside an L-shaped enclosure were analyzed.
Abstract: The natural convection heat transfer in an L -shaped enclosure being filled with Al 2 O 3 /water nanofluid and having an internal heating obstacle is presented in this paper by LBM. The combination of the three topics (L-shaped cavity, hot obstacle and nanofluid) is the main novelty of the present study. The statistics focused specifically on the effects of different key parameters same as Ra number (10 3 –10 6 ), aspect ratio of the channel (0.2–0.6), nano-particle volume fraction of (0–0.05), position and height of the hot obstacle and nanoparticle diameter (20–80 nm) on the heat transfer inside the L -shaped enclosure. The average Nusselt numbers were also calculated for the obstacle sides. The obtained results showed that the streamlines and isotherm lines had different patterns at different Ra numbers, aspect ratio and the height of obstacle. The heat transfer phenomena were highly affected by the heating obstacle position. With the nanofluid and the reducing AR, the increasing Ra number, the decreasing nanoparticle diameter and the increasing height of the obstacle, an increase in the heat transfer and the individual Nusselt number appeared. Moreover, the maximum Nusselt number was observed when the heating obstacle was located in the lower position inside the left wall.

135 citations


Journal ArticleDOI
TL;DR: In this paper, the effects of using nanofluids and integrating the solar still with external condenser have been studied numerically, and the performance of the modified desalination system is evaluated and compared with that of the conventional one under the same meteorological conditions.
Abstract: The effects of using nanofluids and integrating the solar still with external condenser have been studied numerically. The performance of the modified desalination system is evaluated and compared with that of the conventional one under the same meteorological conditions. Theoretical analysis of heat and mass transfer mechanisms for the solar stills has been developed. Numerical calculations had been performed on the solar stills in Kafrelsheikh city, Egypt (31.07°N latitude and 30.57°E longitude) for different nanomaterial concentrations and providing low pressure to study the effects of these parameters on the daily productivity of the system. The analyses are conducted in the weight concentrations range from 0.02 to 0.3% for aluminum oxide (Al 2 O 3 ) and cuprous oxide (Cu 2 O) nanoparticles. Thermo-physical properties of the nanofluid are considered by assuming nanofluid is a single-phase fluid. The simulation results are in a good agreement with the published experimental data. The daily efficiency of the modified still is 84.16% and 73.85% when using Cu 2 O and Al 2 O 3 nanoparticles, respectively, with operating the fan. And the daily efficiency when providing low pressure only is 46.23%. In addition, the conventional stills’ daily efficiency was 34%.

135 citations


Journal ArticleDOI
TL;DR: In this article, dithiocarbamate-functionalized graphene oxide (GO-DTC) has been synthesized and applied in removal of cationic dyes; Basic Blue 41 (BB41) and Basic Red 46 (BR46).
Abstract: In this work, dithiocarbamate-functionalized graphene oxide (GO-DTC) has been synthesized and applied in removal of cationic dyes; Basic Blue 41 (BB41) and Basic Red 46 (BR46). Morphology and chemical structure of the prepared GO-DTC were studied by SEM and FTIR analyses. Dye removal from wastewater solutions with variable concentration of dyes, pH, and GO-DTC dosage was evaluated. The experiments suggested a pseudo-second order kinetic model for dye adsorption onto GO-DTC, while dye adsorption isotherm data were found to fit Langmuir model. The adsorption efficiency of synthesized GO-DTC towards BB41 and BR46 was calculated to be 128.5 and 111 mg/g, respectively.

126 citations


Journal ArticleDOI
TL;DR: In this article, a low cost and easily available agricultural waste of coconut shells based activated carbon were utilized as adsorbent to study its viability and efficiency for phenol removal from wastewater.
Abstract: Removal of phenolic pollutants from wastewaters has become mandatory due to stringent environmental regulations and adverse effects on aquatic marine environment. Adsorption process which is most effective process to remove pollutants, hinders its applications in diverse field due to high cost of adsorbents. In this study, a low cost and easily available agricultural waste of coconut shells based activated carbon were utilized as adsorbent to study its viability and efficiency for phenol removal from wastewater. The efficacy of the phenol removal by adsorption process in a batch reactor is evaluated with respect to contact time for effective adsorption and influence of initial phenol concentration on percentage phenol removal. The experimental adsorption data were examined with conventional isotherms models to describe the equilibrium characteristics of adsorption of phenol. The vigorousity and non-linearity inherent in the isotherm models were validated using various traditional linear and non-linear estimation methods namely gradient method, non-linear least square method and hybrid evolutionary optimization. A novel inverse modeling technique based on differential evolution (DE) optimization which is first of this kind for adsorption applications was implemented to estimate the isotherm parameters in their non-linear form. The model predictions from the DE based optimized parameters provided better predictions and closer to experimental values. The percentage removal of phenol from four different adsorbent dosages with constant initial feed concentrations of phenol found to be varying from 63% to 96% as increase in carbon loading at constant liquid flow rate. These experimental results also revealed that coconut shell based activated carbon is a viable cheaper adsorbent for phenols removal from effluent wastewater.

Journal ArticleDOI
TL;DR: In this article, a similarity transformation is used to transmute the governing momentum and energy equations into non-linear ordinary differential equations with appropriate boundary conditions, which are solved by Duan-Rach Approach (DRA).
Abstract: In this work, the unsteady squeezing MHD nanofluid flow and heat transfer between two parallel plates in the attendance of thermal radiation impact and considering Cattaneo–Christov heat flux model instead of conventional Fourier's law of heat conduction are examined. A similarity transformation is used to transmute the governing momentum and energy equations into non-linear ordinary differential equations with the appropriate boundary conditions. The gained non-linear ordinary differential equations are solved by Duan–Rach Approach (DRA). This method allows us to find a solution without using numerical methods to evaluate the undetermined coefficients. This method modifies the standard Adomian Decomposition Method by evaluating the inverse operators at the boundary conditions directly. The impacts of diverse active parameters such as the magnetic parameter, the squeeze number, the volume fraction of nanofluid, the heat source parameter, the thermal relaxation parameter and the radiation parameter on the velocity and temperature profiles are examined. In addition, the value of the Nusselt number is calculated and presented through figures. The outcomes indicate that the temperature distribution is fewer in the case of Cattaneo–Christov heat flux model as compared to Fourier's law. Furthermore, Nusselt number is an incrementing function of heat source parameter, while it is a diminishing function of the thermal relaxation parameter.

Journal ArticleDOI
TL;DR: In this article, mesoporous birnessite-type manganese oxide (δ-MnO2) was synthesized using potassium permanganate and citric acid monohydrate through a simple redox method.
Abstract: In this paper, mesoporous birnessite-type manganese oxide (δ-MnO2) was synthesized using potassium permanganate and citric acid monohydrate through a simple redox method. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET) surface area measurement were employed to characterize the synthetic birnessite. The birnessite was evaluated as an adsorbent for the removal of methylene blue (MB) from the aqueous solution. The effects of birnessite dosage, initial pH, initial concentration and adsorption time, and temperature were investigated by batch experiments, and results showed the mesoporous birnessite possessed high adsorption efficiency and capacity towards MB. Adsorption isotherm and kinetics studies revealed that the equilibrium adsorption data and adsorption kinetics were well-described by Langmuir isotherm model and the pseudo-second-order kinetic model, respectively. Owing to characteristics of low cost, high-efficiency, and energy-saving, the mesoporous birnessite can be used as an efficient adsorbent for dyeing wastewater treatment.

Journal ArticleDOI
TL;DR: In this article, a review of surface microstructure or chemistry of carbonaceous materials as CO 2 adsorbents with emphasis on the reactions of surface functionalization and mechanism on the carbons with different features is presented.
Abstract: Carbon capture and storage is a crucial technology for reducing atmospheric CO 2 emissions from power plants and other industrial facilities. While many technologies have been developed, the high cost and energy requirements of current CO 2 capture methods still are the primary barriers. Adsorption is one of the cost-effective options for CO 2 capture because of its low energy requirement, cost advantage, and ease of applicability over a relatively wide range of temperature and pressure. However, the success of adsorption methods depends on the development of the adsorbents with high CO 2 selectivity and capacity and easy regeneration. Although some adsorbents exhibited good CO 2 adsorption capacity, their adsorption for water vapor is an important issue for this purpose because water usually exists in flue gas streams. Activated carbons are proposed as suitable candidates for CO 2 capture: they do not require moisture removal, present a high CO 2 capacity at ambient pressures, and are easy to regenerate. However, the low selectivity to CO 2 for activated carbons is the restriction. This article reviews recent advances in surface microstructure or chemistry of carbonaceous materials as CO 2 adsorbents with emphasis on the reactions of surface functionalization, CO 2 adsorption performance and mechanism on the carbons with different features.

Journal ArticleDOI
TL;DR: In this article, a crayfish shell was pyrolyzed at 300, 450 and 600 °C (CS600) to identify the optimum temperature for improving the binding capacity of the produced biochar.
Abstract: In this study, crayfish shell was pyrolyzed at 300 (CS300), 450 (CS450) and 600 °C (CS600) to identify the optimum temperature for improving the binding capacity of the produced biochar. The removal efficiency of biochars was assessed following mono-element sorption of Pb(II) under batch sorption and fixed-bed column experiments. The effect of pH and ionic strength on Pb(II) sorption was further investigated on the most efficient biochar type to understand environmental factors affecting sorption onto crayfish biochar. Besides, this most efficient biochar was further investigated in multi-element sorption (Pb(II), Cu(II) and As(III)) trial to assess the effect of competitive sorption on Pb(II) bioavailability. Pyrolysis temperature had different effects on elemental composition, surface area and active functional groups of the produced biochar. CS600 showed the highest sorption capacity (190.7 mg/g) of Pb(II). Sorption mechanisms were identified following FTIR, SEM, XRD and ICP analyses suggested the participation of physisorption. Sorption of Pb(II) onto crayfish biochar was strongly pH- and ionic strength-dependent as the sorption capacity showed significant reductions at low pH and high ionic strength values. The competitive sorption of Pb(II) with other metal ions (Cu(II) and As(III)) showed its superiority to bind with active sorption sites of biochar as compared with other heavy metals.

Journal ArticleDOI
TL;DR: Pt/TiO 2 -ZnO photocatalytic materials were prepared for the generation of hydrogen gas from water splitting in this article, which reached up to the optimum value of 203 −µmolh −1 g −1 on TiO 2 − ZnO (Ti/Zn = 10).
Abstract: Pt/TiO 2 –ZnO photocatalytic materials were prepared for the generation of hydrogen gas from water splitting. The photocatalysts were characterized by X-ray diffraction (XRD), UV-visible spectra (UV–Vis), scanning electron microscope (SEM) and transmission electron microscope (TEM). The absorption wavelength of TiO 2 was shifted to longer wavelength on Pt/TiO 2 –ZnO. A 400 W mercury arc lamp with a cutoff filter which filter out all the wavelengths under 400 nm as the visible light source. It reached up to the optimum value of 203 µmolh −1 g −1 on TiO 2 –ZnO (Ti/Zn = 10). A catalyst of 0.5 wt% Pt/TiO 2 –ZnO (Ti/Zn = 10) was used and a best hydrogen production rate through water splitting was reaching to 2150 µmolh −1 g −1 . The 0.1 wt% Pt/TiO 2 –ZnO showed a satisfying long-term stability, and 88% and 77% of initial hydrogen productivity still remained after 7 days and 14 days, respectively.

Journal ArticleDOI
Yujiao Kan1, Qinyan Yue1, Dong Li1, Yuwei Wu1, Baoyu Gao1 
TL;DR: In this article, the optimum atmosphere condition for preparing waste tea-based activated carbon by H 3 PO 4 activation, activated carbons were prepared under nitrogen (NAC), air (AAC) and steam (SAC) atmospheres, respectively.
Abstract: In order to study the optimum atmosphere condition for preparing waste tea-based activated carbon by H 3 PO 4 activation, activated carbons were prepared under nitrogen (NAC), air (AAC) and steam (SAC) atmospheres, respectively. The physicochemical properties of the three activated carbons were characterized by N 2 adsorption/desorption and Fourier transform infrared spectroscopy (FTIR). AAC exhibited highest values of the Brunauer–Emmett–Teller (BET) surface area (880 m 2 /g) and total pore volume (0.680 cm 3 /g) than that of NAC (824 cm 2 /g and 0.666 cm 3 /g) and SAC (785 cm 2 /g and 0.629 cm 3 /g). Nevertheless, the adsorption results for oxytetracycline (OTC) showed that SAC had the strongest adsorption capacity than NAC and AAC. The adsorption equilibrium data for OTC adsorption onto the three activated carbons agreed well with the Freundlich model, and the adsorption kinetics were well fitted in pseudo-second-order model. Results revealed that activated carbon prepared under air atmosphere showed the largest BET surface area and activated carbon prepared under steam atmosphere showed the best adsorption capacity.

Journal ArticleDOI
TL;DR: In this article, a double hydroxide (LDH) nanoparticle was synthesized through an anion exchange method and characterized by XRD, IR spectroscopy and SEM.
Abstract: Mg-Al-PO 4 3− layered double hydroxide (LDH) nanoparticle was synthesized through an anion exchange method and characterized by XRD, IR spectroscopy and SEM. The phosphate and Mg 2+ release ability of Mg-Al-PO 4 3− LDH in the 3.5 wt. % NaCl solution was measured by inductively coupled plasma-optical emission spectrometer (ICP-OES). Results showed the release of Mg 2+ from the LDH scaffold along with phosphate anion from LDH gallery, illustrating importance of solubility rather than ion-exchange mechanism. Then, the corrosion inhibitive behavior of Mg-Al-PO 4 3− LDH in 3.5 wt. % NaCl solution was assessed by electrochemical measurements and FE-SEM in comparison with the Mg-Al-NO 3 − LDH. The results showed that Mg-Al-PO 4 3− LDH forms inhibitive film on the mild steel and significantly mitigate corrosion compared to Mg-Al-NO 3 − LDH. The LDHs were also employed in a silane primer top-coated by epoxy-polyamide on mild steel. The results of electrochemical measurements showed significant active corrosion protection ability of Mg-Al-PO 4 3− LDH in the coating with an artificial defect. Furthermore, the adhesion strength of the coating including Mg-Al-PO 4 3− LDH to mild steel after exposure to salt spray (5% NaCl solution) was improved.

Journal ArticleDOI
TL;DR: A new aminophosphonic derivative was synthesized and characterized by UV-vis, IR, 1 H NMR, 13 C NMR and MS spectroscopic methods as discussed by the authors.
Abstract: A new aminophosphonic derivative was synthesized and characterized by UV-vis, IR, 1 H NMR, 13 C NMR and MS spectroscopic methods Its inhibitive action on the carbon steel corrosion in a 05 M H 2 SO 4 solution was studied by polarization curves and electrochemical impedance spectroscopy (EIS) The results indicated that the synthesized compound is an efficient mixed-type inhibitor and its inhibition efficiency increased with increasing the inhibitor concentration The adsorption of the inhibitor on the carbon steel surface obeys Langmuir isotherm and the thermodynamic parameters were obtained The surfaces of carbon steel after exposing to test solutions were examined by atomic force microscopy (AFM) The quantum chemical parameters were calculated in gas and aqueous phases using the density functional method (DFT) The interaction between the inhibitor and Fe (100) surface were performed by molecular dynamic simulations

Journal ArticleDOI
TL;DR: In this article, the synthesis of magnetic biochar from sugarcane bagasse and its applications in heavy metals removal is discussed. But the authors do not consider the use of magnetic adsorbents as potential candidates for wastewater treatment.
Abstract: This paper discusses the synthesis of magnetic adsorbents from agricultural waste and their applications in heavy metals removal. The general methods for preparing magnetic adsorbents and the mechanisms of heavy metal sorption are also reviewed in detail. These mechanisms are related to the utilization of magnetic adsorbents, particularly sugarcane bagasse in heavy metals removal, such as nickel, cadmium, lead, and arsenic. Converting sugarcane bagasse into magnetic adsorbents could solve environmental problems, such as agricultural waste and water pollution. A brief summary of the synthesis of magnetic biochar from sugarcane bagasse and its applications in heavy metals removal is also presented. Thus, this study proposes magnetic-based materials as potential candidates for wastewater treatment, and this adds new dimensions to numerous applications of the carbon family.

Journal ArticleDOI
TL;DR: The present finding suggested that the transformation of Cr(VI) to Cr(III) by novel C. funkei is considered as an effective, ecofriendly and attractive strategy for remediation of Cr (VI) polluted sites.
Abstract: A novel Cr(VI) tolerant bacterial strain AR6 was isolated from leather industrial effluent contaminated soil sample sources and it was identified as Cellulosimicrobium funkei following 16S rDNA gene sequencing. Effect of various physicochemical properties on Cr(VI) reducing ability of the strain was also studied. The results showed that the C. funkei strain AR6 was tolerant to very high concentration of Cr(VI) (1200 µg/ml) and capable of reducing Cr(VI), under a wide range of pH (6–8) and temperature (30–40°C) with an optimum at 7.0 and 35 °C. Further, studies verified that the removal of Cr(VI) was mainly achieved by a metabolism depending on the bioreduction process. The C. funkei strain AR6 reduces and accumulates chromium both in and around the cells, with cell walls acting as the major binding sites for chromium. Raman spectroscopy analysis further confirmed that the chromium immobilization by the cells was in the Cr(III) state. Toxic nature of the reduced product was evaluated by toxicity study using zebrafish embryos ( Danio rerio ) model. Interestingly, when embryo exposed Cr(VI) survival (22.19%) and hatching (26.71%) rates were reduced significantly. However, Cr(VI) intoxicated embryos significantly increased the cardiac function (132 ± 2.65 beat/min) at 60 hpf. Conversely, reduced product excreted less teratogenic effects on zebrafish embryos. The present finding suggested that the transformation of Cr(VI) to Cr(III) by novel C. funkei is considered as an effective, ecofriendly and attractive strategy for remediation of Cr(VI) polluted sites.

Journal ArticleDOI
TL;DR: In this paper, a Fe-Mn oxide adsorbent (FMO) with the Fe/Mn molar ratio of 5:1 was combined to remove phosphate in aqueous solution.
Abstract: A Fe–Mn oxide adsorbent (FMO) with the Fe/Mn molar ratio of 5:1 was combined to remove phosphate in aqueous solution. An apparently irregular surface and heterogeneous porous structure were found in the SEM images of FMO. XPS spectra showed that manganese and iron existed mainly in the +IV and +III oxidation states, respectively. Batch experiments were carried out to investigate the effect of contact time, initial phosphate concentration, temperature, pH and coexisting anions on phosphate removal. Kinetic data of phosphate adsorption onto FMO followed the pseudo-second-order kinetic model, indicating that the phosphate adsorption process was chemisorption. The equilibrium data were analyzed by both Freundlich and Langmuir isotherm models and the Langmuir isotherm model fitted better with the maximum adsorption capacity of 18.4 mg/g at 308 K and pH 7.0. Thermodynamic parameters demonstrated that the phosphate adsorption process was nonspontaneous and endothermic. The phosphate adsorption was critically dependent upon pH value with the maximum adsorption amounts occurring under acidic conditions and decreased with the increase of solution pH. Additionally, the terminal pH increased under acidic conditions while decreased under alkaline conditions. Coexisting anions of nitrate, silicate, sulfate and carbonate had no negative effect on the adsorption of phosphate, inferring the inner-sphere surface complexes were involved in the phosphate adsorption process. Phosphate adsorption by FMO was achieved by electrostatic attraction and replacement of hydroxyl groups. FMO, with large adsorption capability, is a promising attractive adsorbent for phosphate removal from water body.

Journal ArticleDOI
TL;DR: In this paper, the influence of both thermal and solutal stratification on magneto-hydrodynamics (MHD) nanofluid flow along an exponentially stretching sheet is examined.
Abstract: The present analysis concentrates to examine the influence of both thermal and solutal stratification on magneto-hydrodynamics (MHD) nanofluid flow along an exponentially stretching sheet. Moreover, simultaneous effects of mixed convection and viscous dissipation are also analyzed to determine the thermal conductivity within the restricted domain. Energy and concentration equation consist of two important slip mechanisms, namely: the Brownian motion of nanoparticles and the thermophoresis due to concentration difference. By the mean of compatible similarity transformed, a system of PDEs is converted into the system of nonlinear ODEs. The resulting nonlinear ODEs are successfully solved via the implicit finite difference method (FDM). Obtained numerical solutions are plotted for each profile for different and converging values of including parameters. To validate the results, numerical values of Nusselt number are compared with the existing literature for a particular case. Obtained results present the significant impact of each parameter on temperature and concentration. Nanofluid flow behaviour is also observed via velocity profile.

Journal ArticleDOI
TL;DR: A water soluble nano-composite was synthesised using radical polymerization method where polymeric chain was grafted on silica nanoparticle surface Chemical structure of polyacrylamide grafted silica particle (PAAGS) was characterised using FTIR, EDX and SEM images as mentioned in this paper.
Abstract: A water soluble nano-composite was synthesised using radical polymerization method where polymeric chain was grafted on silica nanoparticle surface Chemical structure of polyacrylamide grafted silica particle (PAAGS) was characterised using FTIR, EDX and SEM images Nano-composite application for high-temperature reservoir was investigated by characterising surface activity and measuring rheological properties The transport properties were simulated using STARS simulator CMG to check its suitability for polymer flooding operations The result indicates that a modest viscosity for synthesised nano-composite solution and viscosity retention was improved even at higher temperature Improved performance of PAAGS can be attributed to the formation of complex macromolecular structure The surface properties of silica nanoparticle were improved due to presence of polymer chains at the surface which helped in reduction of interfacial tension and changing the wettability of rock surfaces The simulation studies showed that nano-composite was able to mobilise the residual oil left in the sand pack after secondary recovery

Journal ArticleDOI
TL;DR: In this paper, the preparation of activated carbon fiber (ACF) with cotton as raw precursor via microwave assisted H3PO4 activation was explored, where the influence of microwave power, activation time, and acid concentration on the properties of ACF was investigated.
Abstract: The preparation of activated carbon fiber (ACF) with cotton as raw precursor via microwave assisted H3PO4 activation was explored in the present study. The influence of microwave power, activation time and acid concentration on the properties of activated carbon fiber was investigated. The ACF with maximum surface area and total pore volume of 1370 m2/g and 0.98 cm3 was prepared at microwave input power of 640 W, activation time of 10 min and H3PO4 concentration of 50% (Wt.). The ACF was tested with methylene blue (MB) dye adsorption and the equilibrium adsorption capacity was 476 mg/g, with the adsorption isotherm following the Langmuir isotherm model. The adsorption kinetic followed the pseudo-second-order kinetic model, while the adsorption mechanism was well described by the film diffusion model. The experimental results indicated the potential of cotton as good precursor for the preparation of ACF with promising adsorption capacity by microwave heating.

Journal ArticleDOI
TL;DR: In this paper, the problem of oblique stagnation point flow using Jeffery nanofluid as a rheological fluid model was investigated and the effects of thermophoresis and Brownian motion were taken into account.
Abstract: This study investigates the problem of oblique stagnation point flow using Jeffery nanofluid as a rheological fluid model. Effects of thermophoresis and Brownian motion are taken into account. The governing nonlinear partial differential equations for the flow field are obtained and then converted to ordinary differential equations via suitable transformations. Consequential highly non-linear system of differential equations is solved numerically through mid-point integration as a basic scheme along with Richardson's extrapolation as an enhancement scheme and analytical results are also obtained using optimal homotopy analysis Method (OHAM). Non-dimensional velocities, temperature and concentration profiles are expressed through graphs. Numerical values of local skin friction coefficients, local heat and mass flux are tabulated numerically as well as analytically for various physical parameters emerging in our flow problem. The obtained results revealed that both normal and tangential skin friction coefficients decrease with an increase in Jeffery fluid parameter. It is also observed that an enhancement in Thermophoresis and Brownian motion parameters leads to a reduction in heat flux at the wall. Comparison of numerical data is made with previous existing literature to confirm accuracy of present study for the case of Newtonian fluid.

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TL;DR: In this paper, a review of membrane processes that may be used in zero liquid discharge (ZLD) approaches is presented, as well as potential solutions and innovative technologies for improving their performance.
Abstract: The environmental impacts of brine disposal from seawater desalination plants and wastewater treatment plants represent a subject of growing concern; thus, determining the potential applicability of zero liquid discharge (ZLD) for water treatment is crucial. Membrane-based technologies are a potentially attractive strategy that can be used to reach this goal. Recent studies have highlighted that integrating a series of membrane processes is a viable approach to achieving ZLD for industrial use. However, a relatively limited number of reports have been published on the challenging problems encountered with ZLD approaches. Here, we provide a review of membrane processes that may be used in ZLD approaches and describe their problems as well as potential solutions and innovative technologies for improving their performance. Furthermore, the energy consumption of the different approaches is calculated and analyzed because it represents a major contributor to the total cost, and investments in innovative technologies are discussed. Finally, the prospects for membrane-based ZLD and further research are highlighted.

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TL;DR: In this article, the textile wastewater concentration, pH effects and phosphorus and nitrogen source effects on microalgae growth and lipid accumulation in Chlorella sp. G23 were investigated.
Abstract: The organic materials, nitrogen and phosphate nutrients in industrial textile wastewater could be utilized for algal growth. In order to increase algal wastewater treatment processing cost efficiency, microalgae collected in Taiwan could be grown using these wastewaters to produce biodiesel. The textile wastewater concentration, pH effects and phosphorus and nitrogen source effects on microalgae growth and lipid accumulation in Chlorella sp. G23 were investigated. The results showed the highest total fatty acid methyl ester content (20 ± 4%) when microalgae G23 was cultivated using textile wastewater, K2HPO4 (4 mg/L) and urea (1 g/L) at pH 10 with aeration (carbon dioxide sparging). The nitrogen source type had no effect on the overall NH4+-N and COD removal efficiency (75 ± 3%).

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TL;DR: In this article, a facile and inexpensive electrochemical method was used to synthesize magnetite nanoparticles (MNPs) using X-Ray diffraction pattern (XRD), Fourier transform infrared (FTIR), field emission scanning electron microscope (FESEM), dynamic light scattering (DLS) and vibrating sample magnetometer (VSM) analysis.
Abstract: Ferro magnetic iron oxide (Fe3O4) nanoparticles (NPs) were prepared through a facile and inexpensive electrochemical method. Characterization studies on the generated magnetite nanoparticles (MNPs) was carried out using X-Ray diffraction pattern (XRD), Fourier transform infrared (FTIR), field emission scanning electron microscope (FESEM), dynamic light scattering (DLS) and vibrating sample magnetometer (VSM) analysis. The synthesized material was used as a heterogeneous electro-Fenton catalyst in order to decolorize C.I. Acid Red 14 and C.I. Acid Blue 92 solutions. Graphite electrode Modified with carbon nanotubes (CNTs) were used as cathode in both synthesis and electro-Fenton processes. The effect of operational factors like pH range, initial dye concentration, Fe3O4 loading, current intensity and electrolyte (NaCl) dosage on dye removal efficiency was investigated. Remarkable discoloration in wide range of pH illustrated the superior catalytic potential of MNPs. Furthermore, the recyclability of Fe3O4 NPs after magnetic separation, the prevention of their entrance into the environment as a secondary pollutant and the promoted electro generation of hydrogen peroxide at the surface of cathode due to the presence of CNTs are the additional advantages of this study.

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TL;DR: In this article, an anionic biodegradable surfactant for application in chemical enhanced oil recovery (EOR) process was synthesized from palm oil via trans-esterification process.
Abstract: The present work deals with synthesis of an anionic biodegradable surfactant for application in chemical enhanced oil recovery (EOR) process. Alpha sulfonated ethyl ester (α-SEE) was synthesized from palm oil via trans-esterification process. The surfactant was characterized by FTIR, GC, TGA, FE-SEM and EDX analyses. Critical micelle concentration (CMC) was determined by surface tension measurement at air–aqueous interface. The efficiency of α-SEE was studied by calculating the interfacial tension (IFT) between crude oil and surfactant solution, and by investigating the ability of the surfactant to alter the wettability nature of carbonate and quartz surfaces. Salt effect was studied at CMC of surfactant to obtain an ultra-low IFT value of the order of 10−3 mN/m at optimal salinity. Addition of organic alkali also showed synergistic effect on IFT between crude oil and surfactant solution. The surfactant favorably altered the wettability of oil-wet carbonate and quartz surfaces to water-wet, which is desirable for oil recovery. The surfactant showed potential application in EOR owing to its enhanced interfacial properties and rock-wetting characteristics. Flooding experiments were conducted with surfactant slugs at different α-SEE concentrations to achieve about 25%–27% additional oil recoveries after conventional flooding.