Investigations of nickel (II) removal from aqueous effluents using electric arc furnace slag

The tendency of electric arc furnace (EAF) slag to the adsorb nickel(II) from aqueous solution has been investigated through batch experiments. Scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and Energy Dispersive X-Ray (EDX) Analysis. Analysis was characterized in order to give inside to the properties of electric arc furnace slag (EAFS). The adsorption result revealed that the maximum up take by the EAFS was 160.92mg/g at an equilibrium time of 216hr. The pseudo-second order kinetic fitted well with the kinetic data, showing a high determination coefficient (R2) of over 0.996. The adsorption isotherms of nickel(II) on this adsorbent for both linear and non linear isotherms were well described by Langmuir model, this is because it shown a good fitting to the experimental data when compared to other isotherm models. Moreover the nickel(II) adsorption was found to be dependent on the adsorbent dosage, contact time and initial metal ion concentration. From the result it can be deduced that EAFS could be used to effectively adsorb nickel(II) from aqueous solution

Surface Modification Effects on CNTs Adsorption of Methylene Blue and Phenol

This study compares the adsorption capacity of modified CNTs using acid and heat treatment. The CNTs were synthesized from acetone and ethanol as carbon sources, using floating catalyst chemical vapor deposition (FC-CVD) method. energy-dispersive X-ray spectroscopy (EDX) and Boehm method revealed the existence of oxygen functional group on the surface of CNTs. Heat modification increases the adsorption capacity of as-synthesized CNTs for methylene blue (MB) and phenol by approximately 76% and 50%, respectively. However, acid modification decreases the adsorption capacity. The equilibrium adsorption data fitted the Redlich-Peterson isotherm. For the adsorption kinetic study, the experimental data obeyed the pseudo-second-order model. Both modifications methods reduced the surface area and pore volume. The studies show that the adsorption of MB and phenol onto modified CNTs is much more influenced by their surface functional group than their surface area and pore volume

Recent trends in biodiesel production from commonly used animal fats

Changes in climate due to the enormous amount of carbon dioxide emissions have really encouraged the development of energy sources that are renewable, sustainable, and eco-friendly. The development of alternative energy sources can also be attributed to the rapid decrease in resources of fossil energy. Biodiesel has gained significant interest in recent years due to its fossil fuel–like properties and sustainable and eco-friendly characteristics. However, most biodiesels are expensive because of the high cost of feedstock largely based on edible vegetable oil sources. The use of animal fats waste as cost effective feedstock in biodiesel production has gained considerable attention in recent years. Although, most studies regarding the use of animal wastes as feedstock in biodiesel production are still in the early stages, the advantages of this type of feedstock have been highlighted in the literature. However, most studies have not focus on the recent advances in the use of animal fats waste. The studies on the use of novel approach have been reported in isolation. Therefore, this current study attempts to highlight recent developments of the most commonly used animal fats waste in the production of biodiesel. In addition, emphasis was given to the most appropriate production technique, catalyst, energy requirement, and optimum reaction conditions

Synthesis of poly(acrylonitrile-co-divinylbenzene-co-vinylbenzyl chloride)-derived hypercrosslinked polymer microspheres and a preliminary evaluation of their potential for the solid-phase capture of pharmaceuticals

Poly[acrylonitrile (AN)‐co‐divinylbenzene (DVB)‐co‐vinylbenzyl chloride (VBC)] terpolymers were synthesized by precipitation polymerization in the form of porous polymer microspheres. The poly(AN‐co‐DVB‐co‐VBC) polymers were then hypercrosslinked, via a Friedel‐Crafts reaction with FeCl3 in nitrobenzene, to provide a significant uplift in the specific surface areas of the polymers. FTIR spectra of the hypercrosslinked poly(AN‐co‐DVB‐co‐VBC)s showed that the chloromethyl groups derived from VBC were consumed by the Friedel‐Crafts reactions, which was consistent with successful hypercrosslinking. Hypercrosslinking installed a number of new, small pores into the polymers, as evidenced by a dramatic increase in the specific surface areas upon hypercrosslinking (from ∼530 to 1080 m2 g−1). The hypercrosslinked polymers are very interesting for a range of applications, not least of all for solid‐phase extraction (SPE) work, where the convenient physical form of the polymers (beaded format), their low mean particle diameters, and narrow particle size distributions, as well as their high specific surface areas and polar character (arising from the AN residues), make them attractive candidates as SPE sorbents. In this regard, in a preliminary study one of the hypercrosslinked polymers was utilized as an SPE sorbent for the capture of the polar pharmaceutical diclofenac from a polar environment

Effect of solvents on the extraction of Kacip Fatimah (Labisia pumila) leaves

This study aimed to ascertain the effect of solvents on the extraction of some bioactive compound from Kacip Fatimah (Labisia pumila) leaves was investigated. The main compound identified using High Performance Liquid Chromatography was gallic acid. Thus, the solvents tested were water (H2O), ethanol (EtOH), ethyl acetate (EA) and hexane (Hex) as the extraction solvents with 40 °C temperature and four hour extraction time using Solid Liquid Extraction (SLE). Result showed that water was the best solvent for extraction of Kacip Fatimah (Labisia pumila) gave higher yield (13.42 wt. %) followed by ethanol (5.96 wt. %), ethyl acetate (2.46 wt. %) and hexane (1.29 wt. %). This is believed to give good information for particular extraction processes in different polarities of solvents

The synthesis and characterisation of porous thioamide-sulfonated-modified poly(acrylonitrile-co-divinylbenzene-80) as a potential sorbent to capture polar analytes

Pharmaceuticals contain biologically active components that can pollute water courses as a result of the excretions from individuals and/or uncontrolled release of residues from chemical plants, and they can pose a hazard to health. Pharmaceutical residues can persist at low concentrations in the environment, and thus may be potentially harmful to aquatic animals and to humans. Controlling and monitoring such residues are therefore a prime interest, for example, a solid-phase extraction uses solid sorbents to purify and preconcentrate the residues prior to their chemical analysis. In the present study, poly (acrylonitrile-co-divinylbenzene-80) sorbents are synthesised by varying the comonomer feed ratios under precipitation polymerisation conditions to deliver a family of porous polymer microspheres. Acrylonitrile confers polar characters onto the sorbents, and the acrylonitrile-derived nitrile groups can be chemically transformed via polymer-analogous reactions into thioamide and sulfonated residues which make the sorbents even more suitable for the capture of polar analytes, including selected pharmaceuticals. The utility of the porous thioamide-sulfonated containing sorbents is demonstrated via the dispersion-solid phase extraction of mefenamic acid from aqueous media; mefenamic acid is an anthranilic acid derivative which is a potent, non-steroidal anti-inflammatory drug which is found in environmental waters at low concentrations

The synthesis and characterisation of porous and monodisperse, chemically modified hypercrosslinked poly(acrylonitrile)-based terpolymer as a sorbent for the adsorption of acidic pharmaceuticals

The synthesis and characterization of porous poly(acrylonitrile(AN)-co-divinylbenzene-80 (DVB-80)-co-vinylbenzylchloride (VBC)) polymers with high specific surface areas and weak anion-exchange character have been successfully researched. The hypercrosslinked (HXL) microspheres were chemically modified with 1,2-ethylenediamine (EDA) to enhance the adsorption selectivity of the HXL materials. The zeta potential of EDA-modified HXL poly(AN-co-DVB-80-co-VBC) revealed that the surface of the modified terpolymer was positively charged. The FT-IR spectra of the chemically modified hypercrosslinked poly(AN-co-DVB-80-co-VBC) showed that the nitrile groups derived from the AN unit were utilised by the presence of diamine groups. The BET-specific surface areas of the EDA-modified hypercrosslinked poly(AN-co-DVB-80-co-VBC) was 503 m2 g-1; meanwhile, the specific surface area of the HXL terpolymer was 983 m2 g-1. The adsorption isotherm data were well fitted by both the Langmuir and Freundlich models, whereas the adsorption kinetics followed the pseudo-second-order kinetic model. This study confirms that the EDA-modified hypercrosslinked poly(AN-co-DVB-80-co-VBC) terpolymer is a potential adsorbent for the adsorption of acidic pharmaceuticals

Effect of dilution and operating parameters on ammonia removal from scheduled waste landfill leachate in a lab-scale ammonia stripping reactor

A lab-scale ammonia stripping reactor was used to treat raw and diluted (1:1) scheduled waste landfill (SWL) leachate containing ammonia-nitrogen (NH3-N). Operating parameters such as air-liquid ratio, hydrated lime [Ca(OH)2] dosage, types of packing materials and packing heights were investigated with central composite design (CCD) of response surface methodology (RSM) was used to optimize the parameters affecting NH3-N removal from the leachate. The percentage removal on turbidity, colour and phosphate were also evaluated in this study. It was observed that the optimal conditions obtained from desirable response (NH3-N removal) for raw leachate were predicted at air–liquid ratio of 70, Ca(OH)2 dosage of 5 gL-1, packing height of 60 cm and types of packing material was number 3 (nonwoven polyester) while for diluted leachate these were 70, 6 gL-1, 60 cm and Type 3 (nonwoven polyester), respectively. Quadratic RSM predicted the maximum NH3-N removal to be 78% for raw leachate and 81% for diluted leachate at these optimal conditions concurred with the experiment which successfully removed 76% and 80% of NH3-N, respectively. However, higher removal efficiencies of turbidity (97%), colour (88%) and phosphate (93%) was observed in the treatment with diluted leachate compared to raw leachate merely up to 55%, 34% and 49%, respectively. The finding showed that the difference in the removal of NH3-N in diluted and raw SWL leachate was insignificant. However, turbidity, colour and phosphate showed a significant reduction in the diluted leachate during the treatment. The study suggests that the dilution of SWL leachate does not present a significant effect on the removal of ammonia in the stripping reactor

Effect of synthesis condition on the growth of SWCNTs via catalytic chemical vapor deposition

Single-walled carbon nanotubes (SWCNTs) were synthesized by catalytic chemical vapor deposition (CCVD) of ethanol (C2H5OH) over Fe-Mo-MgO catalyst by using argon as a carrier gas. The reaction conditions are important factors that influence the yield and quality of carbon nanotubes. The effects of temperature and flow rate of carrier gas were investigated to increase the yield of carbon nanotubes. The synthesized carbon nanotubes were characterized by scanning electron microscopy, transmission electron microscopy, X-Ray diffraction and thermo-gravimetric analysis. The results showed that the growth of carbon nanotubes wass effectively influenced by the reaction ambience and the synthesis condition. The temperature and flow rate of carrier gas played a key role in the yield and quality of synthesized CNTs. The estimated yield of synthesized carbon nanotubes was almost over 70%

A CFD analysis on the effect of vortex finder and cylindrical length on cyclone hydrodynamics and centrifugal forces

The article presents a Computational Fluid Dynamics (CFD) calculation to predict and to evaluate the flow field and centrifugal forces of gas cyclones. The numerical solutions were carried out using commercial CFD code FLUENT 6.0. The problem of modelling highly swirling flow is overcame by means of an algebraic turbulence model, and all the features of the experimentally observed gas flow in a cyclone are shown to be computationally reproduced. It was found that CFD simulations predict excellently the axial and tangential velocity with an average deviation of ± 0.5 m/s from the presented experimental data. The physical mechanism for prolonged cyclone cylindrical body and vortex finder has also been successfully elucidated. Specifically, results obtained from the computer modelling exercise have demonstrated that CFD with RSM turbulence model is suitable for modelling a flow field and hydrodynamic of cyclone