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The Use Of Membranes And Membrane Bioreactors For Wastewater Treatment By: Yasmine Healey Submitted: December 4th 2021 Chemical Engineering, Yasmine Healey

Featured Student Work

In the face of water shortages, population growth, and climate change, improvements in wastewater treatment operations and technology are necessary to reduce the over exploitation of freshwater resources around the world. Conventional wastewater treatment operations have succeeded in the past to treat industrial and municipal wastewater, however with increasing water demands and ever-changing environmental regulations, new and improved technology is necessary for a sustainable future. Membrane filtration and membrane bioreactors have increased in popularity as a new and improved method for wastewater treatment. Membrane bioreactors as well as various membrane filtration systems were studied in this report including their unit …

Hydrothermal Conversion Of Neutral Sulfite Semi-Chemical Red Liquor Into Hydrochar, Ramy Gamgoum, Animesh Dutta, Rafael M. Santos, Yi Wai Chiang

Faculty Publications and Scholarship

Hydrochar was produced from neutral sulfite semi-chemical (NSSC) red liquor as a possible bio-based solid fuel for use in power generation facilities. Hydrothermal conversion (HTC) experiments were conducted using a fixed liquor-to-water volume ratio of 1:8 and reaction time of 3 h. Solutions were processed using different chemical additives, pH and temperature conditions to determine the optimum conditions required for producing a high energy content solid fuel. The hydrochar samples produced were analyzed by ultimate, thermogravimetric (TGA) and Fourier transform infrared spectroscopy (FTIR) analyses to determine physicochemical properties that are important for utilization as a fuel. The residual process liquids …

Co2 Energy Reactor – Integrated Mineral Carbonation: Perspectives On Lab-Scale Investigation And Products Valorization, Rafael M. Santos, Pol C. M. Knops, Keesjan L. Rijnsburger, Yi Wai Chiang

Faculty Publications and Scholarship

To overcome the challenges of mineral CO2 sequestration, Innovation Concepts B.V. is developing a unique proprietary gravity pressure vessel (GPV) reactor technology and has focussed on generating reaction products of high economic value. The GPV provides intense process conditions through hydrostatic pressurization and heat exchange integration that harvests exothermic reaction energy, thereby reducing energy demand of conventional reactor designs, in addition to offering other benefits. In this paper, a perspective on the status of this technology and outlook for the future is provided. To date, laboratory-scale tests of the envisioned process have been performed in a tubular “rocking autoclave” reactor. …

Nickel Extraction From Olivine: Effect Of Carbonation Pre-Treatment, Rafael M. Santos, Aldo Van Audenaerde, Yi Wai Chiang, Remus I. Iacobescu, Pol Knops, Tom Van Gerven

Faculty Publications and Scholarship

In this work, we explore a novel mineral processing approach using carbon dioxide to promote mineral alterations that lead to improved extractability of nickel from olivine ((Mg,Fe)2SiO4). The precept is that by altering the morphology and the mineralogy of the ore via mineral carbonation, the comminution requirements and the acid consumption during hydrometallurgical processing can be reduced. Furthermore, carbonation pre-treatment can lead to mineral liberation and concentration of metals in physically separable phases. In a first processing step, olivine is fully carbonated at high CO2 partial pressures (35 bar) and optimal temperature (200 °C) with the addition of pH buffering …

Utilization Of Carbonated Bof Slag As Partial Replacement Of Aggregate In Cement Mortars, Marius Bodor, Rafael M. Santos, Geanina Cristea, Muhammad Salman, Özlem Cizer, Remus I. Iacobescu, Yi Wai Chiang, Koen Van Balen, Maria Vlad, Tom Van Gerven

Faculty Publications and Scholarship

After direct mineral carbonation, a material rich in carbonates and with reduced quantities of free oxides is obtained. The aim of this work was to show that such materials can be used in the construction domain. Basic Oxygen Furnace (BOF) slag from the steelmaking process has been traditionally seen as unfit for bounded applications due to its propensity to swelling, resulting from hydration of its high free lime content. Here, BOF slag was crushed to suitable particle sizes, carbonated in an aqueous solution of carbonic acid, and utilized to replace 50% of natural sand aggregate in cement mortars. The mechanical …

Distinguishing Between Carbonate And Non-Carbonate Precipitates From The Carbonation Of Calcium-Containing Organic Acid Leachates, Rafael M. Santos, Yi Wai Chiang, Jan Elsen, Tom Van Gerven

Faculty Publications and Scholarship

Two organic acids were trialled for the extraction of calcium from steelmaking blast furnace slag for the purpose of precipitated calcium carbonate (PCC) production: succinic and acetic acids. While the leaching performance of succinic acid was superior, carbonation of its leachate did not result in the production of PCC, but rather the precipitation of calcium succinate, and only after the use of pH buffering agents (sodium hydroxide or bicarbonate). In contrast, carbonation of the acetic acid leachate resulted in the production of PCC, also with the aid of buffering agents. This discrepancy highlights the need for a combination of chemical, …

Towards Zero-Waste Mineral Carbon Sequestration Via Two-Way Valorization Of Ironmaking Slag, Yi Wai Chiang, Rafael M. Santos, Jan Elsen, Boudewijn Meesschaert, Johan A. Martens, Tom Van Gerven

Faculty Publications and Scholarship

A three-stage process was developed to transform blast furnace slag (BFS) into two valuable products: precipitated calcium carbonate (PCC) and zeolitic materials. The conceptualized process aims to simultaneously achieve sustainable CO2 sequestration and solid waste elimination. Calcium is first selectively extracted by leaching with an organic acid, followed by carbonation of the leachate to precipitate CaCO3. In parallel, the hydrothermal conversion of the extracted solid residues in alkali solution induces the dissolution/precipitation mechanism that leads to the formation of micro- and meso-porous zeolitic materials. Leaching selectivity was identified as a key factor in the valorization potential of both products. Acetic …

Chemoorganotrophic Bioleaching Of Olivine For Nickel Recovery, Yi Wai Chiang, Rafael M. Santos, Aldo Van Audenaerde, Annick Monballiu, Tom Van Gerven, Boudewijn Meesschaert

Faculty Publications and Scholarship

Bioleaching of olivine, a natural nickel-containing magnesium-iron-silicate, was conducted by applying chemoorganotrophic bacteria and fungi. The tested fungus, Aspergillus niger, leached substantially more nickel from olivine than the tested bacterium, Paenibacillus mucilaginosus. Aspergillus niger also outperformed two other fungal species: Humicola grisae and Penicillium chrysogenum. Contrary to traditional acid leaching, the microorganisms leached nickel preferentially over magnesium and iron. An average selectivity factor of 2.2 was achieved for nickel compared to iron. The impact of ultrasonic conditioning on bioleaching was also tested, and it was found to substantially increase nickel extraction by A. niger. This is credited to an enhancement …

Effect Of Accelerated Carbonation On Aod Stainless Steel Slag For Its Valorisation As A Co2-Sequestering Construction Material, Muhammad Salman, Özlem Cizer, Yiannis Pontikes, Rafael M. Santos, Ruben Snellings, Lucie Vandewalle, Bart Blanpain, Koen Van Balen

Faculty Publications and Scholarship

Non-stabilized Argon Oxygen Decarburisation (AODNS) slag in powdered form was examined for its carbon dioxide sequestration capacity and for its potential utilization in the fabrication of high value building materials. The curing of the sample was carried out in two accelerated carbonation environments: i) in a carbonation chamber, maintained at atmospheric pressure, 22 °C, 5 vol.% CO₂ and 80% RH; and ii) in a carbonation reactor, where the CO₂ partial pressure (pCO₂) and temperature could be further increased. In the carbonation chamber, an average compressive strength of over 20 MPa, on a 64 cm …

Magnesium Chloride As A Leaching And Aragonite-Promoting Self-Regenerative Additive For The Mineral Carbonation Of Calcium-Rich Materials, Rafael M. Santos, Marius Bodor, Paul N. Dragomir, Andreea G. Vraciu, Maria Vlad, Tom Van Gerven

Faculty Publications and Scholarship

Two approaches for the intensification of the mineral carbonation reaction are combined and studied in this work, namely: (i) the calcium leaching and aragonite promoting effects of magnesium chloride (MgCl2), and (ii) the passivating layer abrasion effect of sonication. The alkaline materials subjected to leaching and carbonation tests included lime, wollastonite, steel slags, and air pollution control (APC) residue. Batch leaching tests were conducted with varying concentrations of additives to determine extraction efficiency, and with varying solids-to-liquid ratios to determine solubility limitations. Aqueous mineral carbonation tests, with and without the use of ultrasound, were conducted applying varying concentrations of magnesium …

Impacts Of Nickel Nanoparticles On Mineral Carbonation, Marius Bodor, Rafael M. Santos, Yi Wai Chiang, Maria Vlad, Tom Van Gerven

Faculty Publications and Scholarship

This work presents experimental results regarding the use of pure nickel nanoparticles (NiNP) as a mineral carbonation additive. The aim was to confirm if the catalytic effect of NiNP, which has been reported to increase the dissolution of CO2 and the dissociation of carbonic acid in water, is capable of accelerating mineral carbonation processes. The impacts of NiNP on the CO2 mineralization by four alkaline materials (pure CaO and MgO, and AOD and CC steelmaking slags), on the product mineralogy, on the particle size distribution, and on the morphology of resulting materials were investigated. NiNP-containing solution was found to reach …

Recent Developments And Perspectives On The Treatment Of Industrial Wastes By Mineral Carbonation - A Review, Marius Bordor, Rafael M. Santos, Tom Van Gerven, Maria Vlad

Faculty Publications and Scholarship

Besides producing a substantial portion of anthropogenic CO2 emissions, the industrial sector also generates significant quantities of solid residues. Mineral carbonation of alkaline wastes enables the combination of these two by-products, increasing the sustainability of industrial activities. On top of sequestering CO2 in geochemically stable form, mineral carbonation of waste materials also brings benefits such as stabilization of leaching, basicity and structural integrity, enabling further valorization of the residues, either via reduced waste treatment or landfilling costs, or via the production of marketable products. This paper reviews the current state-of-the-art of this technology and the latest developments in this field. …

Comparative Study Of Ageing, Heat Treatment And Accelerated Carbonation For Stabilization Of Municipal Solid Waste Incineration Bottom Ash In View Of Reducing Regulated Heavy Metal/Metalloid Leaching, Rafael M. Santos, Gilles Mertens, Muhammad Salman, Özlem Cizer, Tom Van Gerven

Faculty Publications and Scholarship

This study compared the performance of four different approaches for stabilization of regulated heavy metal and metalloid leaching from municipal solid waste incineration bottom ash (MSWI-BA): (i) short term (three months) heap ageing, (ii) heat treatment, (iii) accelerated moist carbonation, and (iv) accelerated pressurized slurry carbonation. Two distinct types of MSWI-BA were tested in this study: one originating from a moving-grate furnace incineration operation treating exclusively household refuse (sample B), and another originating from a fluid-bed furnace incineration operation that treats a mixture of household and light industrial wastes (sample F). The most abundant elements in the ashes were Si …

Accelerated Mineral Carbonation Of Stainless Steel Slags For Co2 Storage And Waste Valorization: Effect Of Process Parameters On Geochemical Properties, Rafael M. Santos, Jens Van Bouwel, Ellen Vandevelde, Gilles Mertens, Jan Elsen, Tom Van Gerven

Faculty Publications and Scholarship

This work explores the mineral carbonation of stainless steel slags in search for a technically and economically feasible treatment solution that steers these waste residues away from costly disposal in landfills and into valuable applications. Argon Oxygen Decarburization (AOD) and Continuous Casting (CC) slags prove ideal for mineral carbonation as their powdery morphology forgoes the need for milling and provides sufficient surface area for high reactivity towards direct aqueous carbonation. Experiments were undertaken using two methodologies: unpressurized thin-film carbonation, and pressurized slurry carbonation. The influence of process parameters (temperature, CO2 partial pressure, time, solids loading) on the slag carbonation conversion …

Ultrasound-Intensified Mineral Carbonation, Rafael M. Santos, Davy Francois, Gilles Mertens, Jan Elsen, Tom Van Gerven

Faculty Publications and Scholarship

Several aspects of ultrasound-assisted mineral carbonation were investigated in this work. The objectives were to intensify the CO₂ sequestration process to improve reaction kinetics and maximal conversion. Stainless steel slags, derived from the Argon Oxygen Decarburization (AOD) and Continuous Casting / Ladle Metallurgy (CC/LM) refining steps, were used for assessing the technical feasibility of this concept, as they are potential carbon sinks and can benefit from reduction in alkalinity (pH) by mineral carbonation. Ultrasound was applied by use of an ultrasound horn into the reaction slurry, where mineral carbonation reaction took place at 50 ^oC for up to …

Effects Of Bioleaching On The Chemical, Mineralogical And Morphological Properties Of Natural And Waste-Derived Alkaline Materials, Yi Wai Chiang, Rafael M. Santos, Annick Monballiu, Karel Ghyselbrecht, Johan A. Martens, Maria Laura T. Mattos, Tom Van Gerven, Boudewijn Meesschaert

Faculty Publications and Scholarship

Bioleaching is a potential route for the valorisation of low value natural and waste alkaline materials. It may serve as a pre-treatment stage to mineral carbonation and sorbent synthesis processes by increasing the surface area and altering the mineralogy of the solid material and by generating an alkaline rich (Ca and Mg) aqueous stream. It may also aid the extraction of high value metals from these materials (e.g. Ni), transforming them into valuable ore reserves. The bioleaching potential of several bacteria (Bacillus circulans, Bacillus licheniformis, Bacillus mucilaginosus, Sporosarcina ureae) and fungi (Aspergillus niger, Humicola grisea, Penicillium chrysogenum) towards the alteration …

Developments On Wetting Effects In Microfluidic Slug Flow, Rafael M. Santos, Masahiro Kawaji

Faculty Publications and Scholarship

Wetting effects form a dimension of fluid dynamics that becomes predominant, precisely controllable and possibly useful at the micro-scale. Microfluidic multiphase flow patterns, including size, shape and velocity of fluidic particles, and mass and heat transfer rates are affected by wetting properties of microchannel walls and surface tensions forces between fluid phases. The novelty of this field, coupled to difficulties in experimental design and measurements, means that literature results are scarce and scientific understanding is incomplete. Numerical methods developed recently have enabled a shortcut in obtaining results that can be perceived realistic, and that offer insight otherwise not possible. In …

Stabilization Of Basic Oxygen Furnace Slag By Hot-Stage Carbonation Treatment., Rafael M. Santos, Da Ling, Amin Sarvaramini, Muxing Guo, Jan Elsen, Faïçal Larachi, Georges Beaudoin, Bart Blanpain, Tom Van Gerven

Faculty Publications and Scholarship

Treatment and disposal of Basic Oxygen Furnace (BOF) slag, a residue of the steel production process characterized by high basicity and propensity for heavy metal leaching, is a costly burden on metallurgical plants; a sustainable valorization route is desired. The stabilization of BOF slag utilizing hot-stage carbonation treatment was investigated; this approach envisions carbonation during the hot-to-cold pathway followed by the material after the molten slag is poured and solidified. Three experimental methodologies were employed: (i) in-situ thermogravimetric analyzer (TGA) carbonation was used to assess carbonation reaction kinetics and thermodynamic equilibrium at high temperatures; (ii) pressurized basket reaction carbonation was …

Strategic Selection Of An Optimal Sorbent Mixture For In-Situ Remediation Of Heavy Metal Contaminated Sediments: Framework And Case Study, Yi Wai Chiang, Rafael M. Santos, Karel Ghyselbrecht, Valérie Cappuyns, Johan A. Martens, Rudy Swennen, Tom Van Gerven, Boudewijn Meesschaert

Faculty Publications and Scholarship

Aquatic sediments contaminated with heavy metals originating from mining and metallurgical activities of aquatic sediments poses significant risk to the environment and human health due to the fact that these sediments not only act as a sink for heavy metals, but can also constitute a secondary source of heavy metal contamination. A variety of sorbent materials has demonstrated the potential to immobilize heavy metals. However, the complexity of multi-element contamination makes choosing the appropriate sorbent mixture and application dosage highly challenging. In this paper, a strategic framework is designed to systematically address the development of an in-situ sediment remediation solution …

Adsorption Of Multi-Heavy Metals Onto Water Treatment Residuals: Sorption Capacities And Applications, Yi Wai Chiang, Karel Ghyselbrecht, Rafael M. Santos, Johan A. Martens, Rudy Swennen, Valérie Cappuyns, Boudewijn Meesschaert

Faculty Publications and Scholarship

Inherently formed iron-based water treatment residuals (WTRs) were tested as alternative sorbents for multi-heavy metal removal from synthetic solutions, contaminated sediments, and surface waters. The WTRs were mainly composed of iron (hydr)oxides and had a high BET surface area (170.7 m²/g), due to the presence of micro- and mesopores. The sorption capacity of WTRs for As(V), Cd²⁺, Pb²⁺ and Zn²⁺ from synthetic solutions surpassed that of a commercially available goethite by 100-400% for single contaminant tests, and by 240% for total sorption in multi contaminant tests. The maximum sorption capacity of WTRs towards As(V), …

Synthesis Of Zeolitic-Type Adsorbent Materials From Municipal Solid Waste Incinerator Bottom Ash And Its Application In Heavy Metal Adsorption, Yi Wai Chiang, Karel Ghyselbrecht, Rafael M. Santos, Boudewijn D. Meesschaert, Johan A. Martens

Faculty Publications and Scholarship

Municipal solid waste incinerator (MSWI) bottom ash (BA) was converted to zeolitic-type adsorbent materials by hydrothermal conversion under strongly alkaline conditions. The conversion product was determined to be a mixture of sodium aluminum silicate hydrate (SASH) (Na2O·Al2O3·1.68SiO2·1.73H2O) and tobermorite (Ca5Si6O16(OH)2·4H2O). The BET specific surface area was 22.1 m2/g, which represented a significant gain compared to the BA (4.6 m2/g) due to the formation of micropores and mesopores. The converted BA demonstrated promising performance for application as a sorbent towards several heavy metals (oxyanions of As(V), and Cd2+, Co2+, Ni2+, Pb2+, and Zn2+). Its performance was found to be generally superior …

Synthesis Of Pure Aragonite By Sonochemical Mineral Carbonation., Rafael M. Santos, Pieter Ceulemans, Tom Van Gerven

Faculty Publications and Scholarship

The objective of this work was to promote the formation of the aragonite polymorph of calcium carbonate, which has some valuable applications in industry, via the mineral carbonation route. The combination of ultrasound with magnesium ions promoted the formation of pure aragonite crystals at optimum conditions. It was possible to synthesize high purity aragonite precipitates at temperatures ranging from 24 ^oC to 70 ^oC, with the resulting powders possessing varying particle size distributions (from sub-micron up to 20 μm) and crystal morphologies (from acicular needles to novel hubbard squash-like particles). Several process parameters were found to influence the …

Process Intensification Routes For Mineral Carbonation, Rafael M. Santos, Tom Van Gerven

Faculty Publications and Scholarship

Mineral carbonation is a realistic route for capture and storage of carbon dioxide. The principal advantages of this approach are the chemical stability and storage safety of mineral carbonates, the opportunities for process integration available, and the potential for conversion of low-value materials into useful products. In this work the valorisation of alkaline waste materials from thermal processes by mineral carbonation utilizing intensified and integrated mineral carbonation routes is explored. Process intensification is the chemical engineering of the 21st century, and aims at providing the paradigm-shifting techniques that will revolutionize the industry. The combination of process intensification and process integration …

Gas-Liquid Slug Formation At A Rectangular Microchannel T-Junction: A Cfd Benchmark Case, Rafael M. Santos, Masahiro Kawaji

Faculty Publications and Scholarship

Computational fluid dynamics (CFD) is an important tool for development of microfluidic systems based on gas-liquid two-phase flow. The formation of Taylor slugs at microchannel T-junctions has been studied both experimentally and numerically, however discrepancies still exist because of difficulties in correctly representing experimental conditions and uncertainties in the physics controlling slug flow, such as contact line and velocity slip. In this paper detailed methods and results are described for the study of Santos and Kawaji [1] on the comparison of experimental results and numerical modeling. The system studied consisted of a rectangular microchannel T-junction nominally 100μm in hydraulic diameter, …

Numerical Modeling And Experimental Investigation Of Gas-Liquid Slug Formation In A Microchannel T-Junction, Rafael M. Santos, Masahiro Kawaji

Faculty Publications and Scholarship

Gas-liquid two-phase flow in a microfluidic T-junction with nearly square microchannels of 113 μm hydraulic diameter was investigated experimentally and numerically. Air and water superficial velocities were 0.018–0.791 m/s and 0.042–0.757 m/s, respectively. Three-dimensional modeling was performed with computational fluid dynamics (CFD) software FLUENT and the volume-of-fluid (VOF) model. Slug flow (snapping/breaking/jetting) and stratified flow were observed experimentally. Numerically predicted void fraction followed a linear relationship with the homogeneous void fraction, while experimental values depended on the superficial velocity ratio UG/UL. Higher experimental velocity slip caused by gas inlet pressure build-up and oscillation caused deviation from numerical predictions. Velocity slip …

In-Situ Measurements Of The Liquid-Phase Sintering Of Zinc Oxide, Mohammad Lutful Arefin

Publications and Scholarship

Polycrystalline ceramic semiconductor devices based on ZnO and several additive oxides show highly non-ohmic current-voltage behavior similar to the Zener diodes. The devices act as an insulator up to a certain electrical field called the breakdown field (EBR) but change into a highly conducting one just above it. Below and above the breakdown field they behave perfectly ohmic. This overall non-linear current-voltage characteristic together with the ability to withstand repeated high power pulses has made metal oxide varistors popular as "surge-arrestors" in electrical circuitry.

ZnO doped with Bi2O3 and Sb2O3 (ZBS), is the basic system for ceramic varistors. Phase formation …

Concentration Dependent Fluorescence Lifetime In Nanocrystalline Y2o3:Eu Phosphors, Harald Kaps, Mohammad Lutful Arefin, Ulrich Herr, Heiko Paul

Publications and Scholarship

Nanocrystalline (Y_1-xEu_x)₂O₃ powder was synthesized via a chemical vapour reaction. X-ray diffraction revealed the structure of cubic yttria with crystallite sizes of about 5 nm. The Eu-dopand concentrations x for the samples in the range from 0.003 up to 0.165 were determined by EDX-spectra. The luminescence of the nanopowders was investigated by continuous and time-resolved UV-fluorescence spectroscopy and compared to a microcrystalline Y₂O₃:Eu phosphor as a reference. The emission spectra show an increasing intensity for higher doping concentrations. However, compared to the microcrystalline material the yield was significantly lower. …