Janusz A. Kozinski

Biosorption of heavy metal ions using wheat based biosorbents – A review of the recent literature

Conventional technologies for the removal/remediation of toxic metal ions from wastewaters are proving expensive due to non-regenerable materials used and high costs. Biosorption is emerging as a technique offering the use of economical alternate biological materials for the purpose. Functional groups like carboxyl, hydroxyl, sulphydryl and amido present in these biomaterials, make it possible for them to attach metal ions from waters. Every year, large amounts of straw and bran from Triticum aestivum (wheat), a major food crop of the world, are produced as by-products/waste materials. The purpose of this article is to review rather scattered information on the utilization of straw and bran for the removal/minimization of metal ions from waters. High efficiency, high biosorption capacity, cost-effectiveness and renewability are the important parameters making these materials as economical alternatives for metal removal and waste remediation. Applications of available adsorption and kinetic models as well as influences of change in temperature and pH of medium on metal biosorption by wheat straw and wheat bran are reviewed. The biosorption mechanism has been found to be quite complex. It comprises a number of phenomena including adsorption, surface precipitation, ion-exchange and complexation.

Preparation and sorption studies of glutaraldehyde cross-linked chitosan copolymers.

Chitosan-glutaraldehyde copolymer sorbents were synthesized by reacting variable weight ratios (low, medium, and high) of glutaraldehyde with fixed amounts of chitosan. Two commercially available chitosan polymers with low (L) and high (H) relative molecular weights were investigated. The chitosan-glutaraldehyde (Chi-Glu) copolymer sorbents are denoted as CPL-X or CPH-X where X denotes the incremental level (X=-1, -2, -3) of glutaraldehyde. The copolymers were characterized using FT-IR spectroscopy and TGA. The solid-solution sorption isotherms in alkaline aqueous solution for the copolymers were characterized using absorbance and emission based spectroscopic methods for p-nitrophenol (PNP) and the arsenate oxoanion HAsO4(2-) species, respectively. The Sips isotherm model was utilized to obtain sorption parameters at pH 8.5 and 295K (i.e. sorbent surface area, sorption capacity and removal efficiency) for each copolymer sorbent. The sorbent surface areas for the low molecular weight chitosan copolymers are listed in parentheses (m(2)g(-1)), as follows: CPL-1 (124), CPL-2 (46.7) and CPL-3 (31.6). The high molecular weight chitosan copolymers are as follows: CPH-1 (79.8), CPH-2 (64.7) and CPH-3 (96.3). The removal efficiencies depend on the pH, temperature, and the relative amounts of sorbate and sorbent. The sorbent removal efficiencies for p-nitrophenol ranged between 7.1% and 49%, and the values for H2AsO4(2-) ranged between 31% to 93% for the low and high molecular weight copolymers.

Contaminant source identification within a building: Toward design of immune buildings

Abstract The level of protection of a building against the intentional or accidental release of chemical agents is crucial. Both scenarios could endanger life and safety of the buildings occupants. Equipping buildings with appropriate chemical sensors can alert the building occupants about the contaminant release. The readings of these sensors can be employed to trace the location of release, and help to take the appropriate actions to minimize the casualties. However, only a limited number of them can be installed due to their initial and operating cost. Moreover, there is no information about the source strength, release time and possible source location. This paper reports the development of a methodology to identify the source location using sensors reading from limited locations. The methodology uses the artificial neural network (ANN) as a statistical analysis integrated with a multi-zone airborne contaminant transport model, CONTAM. To evaluate the applicability of this method, the contaminant dispersion within a building was modeled and the results were integrated to an ANN for the source identification. The prediction made by the trained ANN was then evaluated by predicting the source of the contaminant in 40 extra cases, which had not been seen by the network during the training session. The model was able to predict the source location in more than 90% of the cases when the building was monitored by three or more sensors. The results show that the method can be used to help building designers decide the optimum configuration of the sensors required for a space based on the accuracy level of the source detection.

Microarchitecture for a three-dimensional wrinkled surface platform.

Dr. M. Li, N. Hakimi, Dr. R. Perez, Prof. S. Waldman, Prof. D. K. Hwang Department of Chemical Engineering Ryerson University 350 Victoria Street , Toronto , Ontario M5B 2K3 , Canada E-mail: dkhwang@ryerson.ca Dr. R. Perez Department of Nanobiomedical Science Dankook University Cheonan 330–714 , South Korea Prof. S. Waldman Li Ka Shing Knowledge Institute St. Michael’s Hospital 30 Bond Street , Toronto , Ontario M5B 1W8 , Canada Prof. J. A. Kozinski Lassonde School of Engineering York University 4700 Keele Street , Toronto , Ontario M3J 1P3 , Canada

Preparation and sorption studies of β-cyclodextrin–chitosan–glutaraldehyde terpolymers

β-Cyclodextrin-chitosan-glutaraldehyde terpolymers were synthesized by reacting variable weight fractions of β-cyclodextrin (β-CD) and chitosan (Chi), with a constant amount of crosslinker (glutaraldehyde). The β-CD:Chi:Glu terpolymer sorbents were characterized by FT-IR spectroscopy and TGA. The solid-solution sorption isotherms in aqueous solution for the copolymers were characterized using two spectroscopic methods (UV-Vis and ICAP-OES) for p-nitrophenol (PNP) and the arsenate oxoanion (HAsO(4)(2-)) at alkaline pH conditions. The Sips isotherm model was utilized to obtain sorption parameters at pH 8.5 and 295 K (i.e. sorbent surface area, sorption capacity and removal efficiency) for each copolymer sorbent. The sorbent surface area estimates for the terpolymers at low (T1), medium (T2), and high (T3) weight fractions of β-CD are listed in parentheses (m(2) g(-1)), as follows: T1 (161), T2 (51.2) and T3 (275). The removal efficiencies are dependent on the relative weight fraction of the polysaccharide components (i.e. β-CD and Chi); whereas the removal efficiencies for p-nitrophenolate ranged between 7.3% and 28%, and H(2)AsO(4)(2-) ranged between 23% and 55%.

Valorization of horse manure through catalytic supercritical water gasification.

The organic wastes such as lignocellulosic biomass, municipal solid waste, sewage sludge and livestock manure have attracted attention as alternative sources of energy. Cattle manure, a waste generated in surplus amounts from the feedlot, has always been a chief environmental concern. This study is focused on identifying the candidacy of horse manure as a next generation feedstock for biofuel production through supercritical water gasification. The horse manure was gasified in supercritical water to examine the effects of temperature (400-600°C), biomass-to-water ratio (1:5 and 1:10) and reaction time (15-45min) at a pressure range of 23-25MPa. The horse manure and resulting biochar were characterized through carbon-hydrogen-nitrogen-sulfur (CHNS), inductively coupled plasma-mass spectrometry (ICP-MS), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy and scanning electron microscopy (SEM). The effects of alkali catalysts such as NaOH, Na2CO3 and K2CO3 at variable concentrations (1-2wt%) were investigated to maximize the hydrogen yields. Supercritical water gasification of horse manure with 2wt% Na2CO3 at 600°C and 1:10 biomass-to-water ratio for 45min revealed maximum hydrogen yields (5.31mmol/g), total gas yields (20.8mmol/g) with greater carbon conversion efficiency (43.1%) and enhanced lower heating value of gas products (2920kJ/Nm(3)). The manure-derived biochars generated at temperatures higher than 500°C also demonstrated higher thermal stability (weight loss <34%) and larger carbon content (>70wt%) suggesting their application in enhancing soil fertility and carbon sequestration. The results propose that supercritical water gasification could be a proficient remediation technology for horse manure to generate hydrogen-rich gas products.

Fermentative production of butanol: Perspectives on synthetic biology

Apprehensions relating to global warming, climate change, pollution, rising energy demands as well as fluctuating crude oil prices and supply are leading to a shift in global interest to find suitable alternatives to fossil fuels. This review aims to highlight the many different facets of butanol as an advanced next-generation transportation biofuel. Butanol has fuel properties almost on a par with gasoline, such as high energy content, low vapor pressure, non-hygroscopic nature, less volatility, flexible fuel blends and high octane number. The paper reviews some recent advances in acetone-butanol-ethanol fermentation with special emphasis on the primary challenges encountered in butanol fermentation, including butanol toxicity, solvent intolerance and bacteriophage contamination. The mechanisms for butanol recovery techniques have been covered along with their benefits and limitations. A comprehensive discussion of genetic and metabolic engineering of butanol-producing microorganisms is made for the prospective development of industrially-relevant strains that can overcome the technical challenges involved in efficient butanol production.

Functional polymer sheet patterning using microfluidics.

Poly(dimethylsiloxane) (PDMS)-based microfluidics provide a novel approach to advanced material synthesis. While PDMS has been successfully used in a wide range of industrial applications, due to the weak mechanical property channels generally possess low aspect ratios (AR) and thus produce microparticles with similarly low ARs. By increasing the channel width to nearly 1 cm, AR to 267, and implementing flow lithography, we were able to establish the slit-channel lithography. Not only does this allow us to synthesize sheet materials bearing multiscale features and tunable chemical anisotropy but it also allows us to fabricate functional layered sheet structures in a one-step, high-throughput fashion. We showcased the techniques potential role in various applications, such as the synthesis of planar material with micro- and nanoscale features, surface morphologies, construction of tubular and 3D layered hydrogel tissue scaffolds, and one-step formation of radio frequency identification (RFID) tags. The method introduced offers a novel route to functional sheet material synthesis and sheet system fabrication.

PACs formation and interaction in semipractical flames of liquid fuels

Abstract Results of experiments carried out in semipractical turbulent diffusion flames of heavy fuel oil and its water-emulsion (E10) doped with 10% water are reported. Variations in axial and radial concentrations of Polycyclic Aromatic Compounds (PACs) and their interactions with soot particles were studied. PACs were identified/determined by GC-MS, while soot particles were subjected to particle size analysis by electron microscopy and quantitative image analysis. Thirty-eight PACs were identified in oil and 22 in emulsion flames. High concentrations of some of the PACs detected in the flame (e.g., naphthalene, pyrene) are attributed to their presence in the fuel. Other compounds (e.g., fluorene) were formed very quickly in the initial combustion stages due to pyrosynthesis and decomposition of higher hydrocarbons. Apart from PACs containing only carbon and hydrogen elements, PACs containing heteroatoms of nitrogen, sulfur and oxygen were also found (e.g., 10-azabenzo(a)pyrene, dibenzo(b,d)thiophene, anthraquinone). PACs were mainly formed in the high-temperature fuel-rich region (0.2–0.3 m from the burner nozzle). At a distance over 0.5 m from the burner, PAC destruction predominated. This was caused by their direct transformation to soot and decomposition due to oxidation and dehydrogenation (one-ring aromatic species and aliphatic hydrocarbons from C8 to C24 were mainly formed). Distinctly higher PAC concentrations were found during the combustion of oil, especially in the high-temperature flame zones. This was connected with more intensive pyrolysis/pyrosynthesis processes in fuel oil flames and then the faster PAC formation. The explosive burning of water-emulsion droplets also influences this behavior. The results indicated that the fuel oil combustion in the form of water-emulsion lowers PAC formation in flames and their emissions to the atmosphere. An evident decrease in pyrene and fluorene concentrations was observed, in particular in water-emulsion flames where microexplosion of droplets in the fuel-atomized stream intensified droplet evaporation and fuel vapor mixing with oxidizer, and thus the oxidation process. Although fluorene decomposition was significant in the radial direction, this process was more intensive with the growth of the distance along the flame axis. It was confirmed that the temperature-time history that the pyrolyzing fuel undergoes is a very important physical parameter affecting PAC formation/destruction in semipractical oil flames. It was also showed that PACs can fulfill the role of precursors for soot particles formed in turbulent diffusion heavy liquid hydrocarbon-air flames, playing an essential part in their formation and growth during combustion.

Synthesis of erbium hydroxide microflowers and nanostructures in subcritical water

The effects of temperature, pressure, pH, residence time and reactant concentrations, as well as the presence or absence of CO(2), on the size and morphology of erbium hydroxide particles synthesized in a hydrothermal batch reactor and a diamond-anvil cell (DAC) reactor have been investigated. Several new erbium-based microstructures and nanostructures were obtained that encompass different phases and shapes, including crystalline microflowers, hexagonal microlayers, microsticks and microspheres made from nanoparticles, as well as nanofibers, nanorods and nanolayers. The Er(2)OCO(3)(OH)(2) microflowers are pure, structurally uniform, and mostly free from dislocations. Their crystallinity, morphology, optical properties and structural features have been examined and compared with those of the other phases by field-emission scanning electron microscopy (SEM), x-ray diffraction (XRD), and energy-dispersive x-ray (EDX) analysis, and by Raman, infrared, UV-visible and fluorescence spectroscopy.