Chil-Hung Cheng

Ryerson University · Department of Chemical Engineering

Permanganate (MnO–4 ) ions were adsorbed on carbonate intercalated Co-Al-layered double hydroxide (Co-Al-LDH) and MoS2 and after a while the adsorbed MnO–4 ions were reduced to MnO2. Reduction of adsorbed MnO–4 ion was catalyzed on the surface of carbonate intercalated Co-Al-LDH but MnO–4 ions reacted with MoS2 surface. Adsorption kinetic tests wer...

Permanganate MnO4−) ions were catalytically reduced to MnO2 by water molecules after adsorption on the surface of carbonate intercalated Co–Al-LDH. This reaction was very slow under experimental conditions in the absence of catalyst and was catalyzed by Co–Al-LDH and Co(II) ion had a key role in this process in the pH range of 2.8–13. But, at pH =...

Adsorption of Alizarin Red S (ARS) on graphene oxide/poly(amidoamine) (GO/PAMAM) was studied at different ARS initial concentrations, temperatures, pHs, shaking rates and contact times. Adsorption sites of GO/PAMAM were phenolic –OH (Ph) group of GO and amine groups (–NH2, –NH+ 3 and –NHR+2) of PAMAM dendrimer moieties of GO/PAMAM. At pH = 2 and 31...

Biomimetic and bioinspired membranes are the efficient membrane technology when it comes to multiple usage scenarios, including next generations of biomaterials within the commercial separation applications, as well as, water and wastewater treatment technologies. In recent years, aquaporin biomimetic membranes for water separation have raised cons...

The main objective of this study was to evaluate the effectiveness of various backwash scenarios on fouling cleaning for flux restoration in ultra filtration of simulated latex effluent. The effects of water and injected air flow rates, backwash duration, and transmembrane pressure on the flux restoration were examined. Polycarbonate and Polysulfon...

Graphene oxide/poly(amidoamine) (GO/PAMAM) nanocomposite adsorbed high quantities of congo red (CR) anionic dye in 0.1 M NaCl solution, with the maximum adsorption capacity of 198 mg·g−1. The kinetics and thermodynamics of adsorption were investigated to elucidate the effects of pH, temperature, shaking rate, ionic strength, and contact time. Kinet...

The goal of the current research was to critically examine the role of the shape and the size of contaminated particles for an accurate prediction of membrane fouling phenomenon. Polycarbonate flat membranes (PC) with uniform pore sizes of 0.05 µm and 0.1 µm, in addition to Polysulfone membranes (PS) with molecular weight cut off (MWCO) of 60,000 k...

Zeolites are fascinating and versatile materials which are vital for a wide range of industries, due to their unique structural and chemical properties, which are the basis of applications in gas separation, ion exchange, and catalysis. Given their economic impact, there is a powerful incentive for smart design of new materials with enhanced functi...

The goal of the current research study was to critically examine the role of the shape of contaminated particles for an accurate prediction of membrane fouling phenomenon. Polycarbonate flat membranes with uniform pore sizes of 0.05 µm and 0.1 µm, in addition to Polysulfone membranes with molecular weight cut of 60,000, were used under a constant f...

The goal of the present study was to investigate the influence of latex particle aggregation on membrane fouling attachments and the ultrafiltration performance of simulated latex effluent using Cetyltrimethyl Ammonium Bromide (CTAB) as a cationic surfactant. Hydrophilic polysulfone and ultrafilic flat heterogeneous membranes, with molecular weight...

In this study, graphene oxide was covalently immobilized on silica-coated magnetite and then modified with 2-phenylethylamine to give a nanocomposite of type Fe 3 O 4 @SiO 2 @GO–PEA that can be applied to the magnetic solid-phase extraction of polycyclic aromatic hydrocarbons (PAHs) from water samples. The resulting microspheres (Fe 3 O 4 @SiO 2 @G...

Tha aim of the present study was to develop a series of numerical models for an accurate prediction of the power consumption in ultrafiltration of simulated latex effluent. The developed power consumption model incorporated fouling attachment, as well as chemical and physical factors in membrane fouling, in order to ensure accurate prediction and s...

The objective of the present study was to minimize membrane fouling of a latex solution either through improving the membrane surface charge or using a pretreated feed. Hydrophilic polysulphone (PSU) and Ultrafilic flat membranes, with a molecular weight cutoff (MWCO) of 60 000 and 100 000 dalton, respectively, were implemented under a constant flo...

The objective of the present study was to minimize membrane fouling of a latex solution either through improving the membrane surface charge or using a pretreated feed. Hydrophilic polysulphone (PSU) and Ultrafilic flat membranes, with a molecular weight cut-off (MWCO) of 60000 and 100000 dalton, respectively, were implemented under a constant flow...

In an attempt to maximize the amount of ozone reacting with lignin inside humid wheat straw, some of the ozone-reactive lignin degradation products were washed away before a second ozonolysis delignification stage. The total contact time for the two stages was kept the same as that for a one-stage process for comparison. A significant decrease in t...

This work systematically studies on adding alcohols to alter the crystal growth behavior of ZSM-12, using 1-propanol (1P), 2-propanol (2P), ethylene glycol (EG), 1,3-propanediol (PD), 1,6-hexanediol (HD), diethylene glycol (DEG), triethylene glycol (TEG), and tetraethylene glycol (TTEG) as co-solvents. The effects of co-solvent content, temperature...

Polysulfone (PSU) membranes have been widely applied in microfiltration and ultrafiltration processes due to their excellent properties, such as chemical inertness across the entire pH range, compressive strength, and thermal stability. Despite these advantages, the application of PSU membranes in filtration processes has often been restricted due...

Surfactants are self-assembled compounds that depend on their structure and electric charge can interact as monomer or micelle with other compounds (substrates). These interactions which may catalyze or inhibit the reaction rates are studied with pseudophase, cooperativity, and stoichiometric (classical) models. In this review, we discuss applying...

The aim of the present study was to develop a mathematical model for a better understanding and prediction of the Ultrafiltration membrane fouling, which can be applied to the heterogeneous membrane with non-uniform pore size. Polysulfone flat membrane with a molecular weight cutoff (MWCO) of 60 000 (nominal size of 0.05 μm) was used with a constan...

The aim of the present study was to obtain the predictive models that would allow for the accurate estimation of the depositional and coagulation attachments, at different operational conditions and using heterogeneous membranes with non-uniform pore size. The fouling attachments predicted by the model can in turn be applied in estimation of the ad...

The present invention relates to the modification of the internal surfaces of zeolite crystals via treatment with alcohols containing at least four carbon atoms. The modified zeolites possess high thermal stability and the properties of the modified zeolites can be tailored to provide improved performance for use in separations processes.

The aim of the present study was to develop a fouling attachment model applicable for both hydrophilic and hydrophobic nonuniform pore size membranes. The predictive models found in the present study allow for an accurate estimation of the depositional and coagulation attachments, at a given operating condition and membrane surface charges. The eff...

Metal-organic frameworks (MOFs) are a new class of microporous materials that possess framework flexibility, large surface areas, "tailor-made" framework functionalities, and tunable pore sizes. These features empower MOFs superior performances and broader application spectra than those of zeolites and phosphine-based molecular sieves. In parallel...

Over the past decades, organic-inorganic hybrid polymers have been applied in different fields, including the adsorption of pollutants from wastewater and solid-state separations. In this review, firstly, these compounds are classified. These compounds are prepared by sol-gel method, self-assembly process (mesopores), assembling of nanobuilding blo...

We report an alternative route to modify the morphology and the size of zeolite L (LTL) crystals using diols as co-solvents in the hydrothermal condition. Among the investigated diols, only triethylene glycol (TEG) acts as an efficient organic solvent in facilitating the LTL formation. The powder X-ray diffraction (PXRD) patterns exhibit the co-exi...

We demonstrate an alternative route to tune the morphology of zeolite L crystals using C(2)H(5)OH as the co-solvent in the synthesis gel. A low aspect ratio (0.2 to 0.4) of zeolite L crystals was obtained at lower synthesis temperature (150 °C) and shorter synthesis duration (3 days).

The functionalization of the internal surface of pure-silica MFI zeolite using aliphatic alcohols (1-butanol and 1-hexanol) is reported. Calcined MFI nanoparticles (50, 100, 200, and 500 nm in size) are treated with neat 1-butanol and 1-hexanol under reflux conditions. The 1-butanol loadings on 200 and 500 nm particles are determined to be 0.7 mmol...

The synthesis, characterization, and growth rates of aluminum- and germanium,aluminum-substituted silicalite-1 (Al-silicalite-1, Ge,Al-silicalite-1) materials grown from clear solutions are reported. In the case of aluminum substitution, the crystallinity of the materials as determined by powder X-ray diffraction (PXRD) decreases with increasing al...

The synthesis, characterization, and growth of Ge-silicalite-1 from optically clear solutions are reported. Ge-silicalite-1 is readily formed from optically clear solutions of TEOS, TPAOH, water, and a germanium source at 368 K. X-ray fluorescence (XRF) is used to determine the Si/Ge ratio and indicates that germanium inclusion is typically 30-50%...

Solution 29Si NMR spectroscopy results of zeolite precursor solutions of composition 1 SiO2:4 C2H5OH:0.36/n R+n[OH-]n:20 H2O are reported. This work employs isotopically enriched 29Si materials to aid in spectral interpretation. Using both 1D and 2D methods, spectra of solutions containing tetrapropylammonium hydroxide are wholly consistent with th...

This review summarizes recent small-angle X-ray scattering investigations of the initial stages of zeolite formation and growth. These studies have increased the zeolite science community's understanding of the structures present at the earliest stages of growth, particularly in the case of silicalite-1 formed from so-called ‘clear solution’ synthe...

In situ small-angle X-ray scattering (SAXS) is used to investigate the influence of alcohol identity and content on silicalite-1 growth from clear solutions at 368 K. Several tetraalkyl orthosilicates (Si(OR)4, R = Me, Pr, and Bu) are used to synthesize silicalite-1 from clear solution mixtures comparable to those previously investigated (i.e. 1:0....

Small-angle X-ray scattering (SAXS) has been used to quantify how perturbations of the tetrapropylammonium (TPA) cation structure affect the growth of silicalite-1 from clear solutions at 368 K. Alkyltripropylammonium (RN(C3H7)3 +OH-, R = Me, Et, Bu, and Pe), dialkyldipropylammonium (R2N(C3H7)2 +OH-, R = Et and Bu), and bis-1,6-(tripropylammonium)h...

Reverse w/o microemulsions composed of methyl methacrylate (MMA) forming the oil phase, nonionic surfactants, and water are used for the synthesis of transparent SiO2/PMMA nanocomposites. An inorganic precursor, tetraethoxysilane (Si(OEt)(4), TEOS), is hydrolyzed in the reverse micelles containing aqueous ammonia. During the hydrolysis of TEOS, pol...

This work investigates nanoparticle formation and zeolite growth in several tetraethyl orthosilicate (TEOS)/organocation/water solutions heated at 368 K using small-angle X-ray scattering. The effect of several synthesis parameters including organocation identity, hydroxide content, alkali content, synthesis temperature, ethanol content, and seedin...

Reduction of aqueous RhCl3 with NaBH4 in the presence of poly(vinyl pyrrolidone) (PVP) yields dense spherical nanostructures. The spherical aggregates, which generally have diameters between 10 and 100 nm, are built from smaller 1−3 nm Rh particles. The dense nanostructures are thermally stable beyond 100 °C, and they have a tendency to form ordere...

Water-containing isoprene was partial hydrogenated over δ-alumina-supported eggshell Pd catalysts with a weight-hourly space velocity (WHSV) of 18 h-1 (grams of feed per hour × grams of catalyst) at 40 °C and 30 atm (30.39 kg/cm2) total pressure. The isoprene conversion decreased with time on stream and became almost time invariant at about 50 h, w...

The influences of water poisoning on isoprene-selective hydrogenation over δ-alumina-supported eggshell Pd catalysts were investigated by test reactions at 40 °C and 420 psig of total pressure. Both fresh and water-poisoned catalysts were characterized by fast Fourier transform infrared (FFT-IR) spectroscopy and temperature-programmed desorption (T...

Understanding the mechanism of zeolite nucleation and crystallization will enable the zeolite science community to tune zeolite properties during synthesis in order to accommodate the purposes of various applications. Thus there has been considerable research effort in "deciphering" the mechanism by studying the growth course of tetrapropylammonium...