Richard Holdich

Loughborough University | Lough · Department of Chemical Engineering

Tubular micrometer pore sized sieve type membranes with internal diameter of 14 mm and length of 60 mm containing uniform pores of diameter 10 and 20 μm were used to generate emulsions of sunflower oil dispersed in water and stabilized by Tween 20 using oscillatory flow of the continuous phase. Drop diameters between 30 and 300 μm could be produced...

This article is closed access. It was published in the journal, Industrial and Engineering Chemistry Research [© ACS Publications]: http://pubs.acs.org/page/iecred/about.html Membrane emulsification of sunflower oil in aqueous solutions of 2% (vol/vol) Tween 20 was performed using a stationary disk membrane with a rotating paddle stirrer and, for c...

Particles for subcutaneous depot use encapsulating a model water-soluble drug have been produced from poly(lactic-glycolic acid) (PLGA) using a membrane emulsification-solvent evaporation technique. The release behaviour, mainly the change in size and inner morphology are reported. During release, the particles initially swelled in size, then reduc...

Contenido: Tecnología de separación sólido-líquida; Fundamentos de la filtración; Fundamentos de la sedimentación; Filtros; Técnicas del tratamiento previo; Filtración para clarificar; Sedimentación y coagulación; Separación centrífuga; Procesos posteriores al tratamiento; Tecnología de membrana; Equipo de proceso y cálculos de la filtración; Apénd...

The conversion of industrial crops to energy has received significant attention recently as a means to reduce carbon emissions and meeting the renewable energy targets. Samples of whole crop maize (Zea mays L.) were pre-treated in tap water using a novel microbubble-enhanced dielectric barrier discharge (DBD) plasma reactor that generates highly re...

Hydrochars produced from hydrothermal carbonisation of faecal simulant (FS) at 180 °C for 30 min and sewage sludge treated via CAMBI process at 165 °C for 30 min were used for adsorption of organic pollutants in effluent from an anaerobic digester (AD). The adsorption potential of the hydrochars investigated was compared with that of a commercial p...

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Membrane emulsification has the potential to revolutionize the energy‐efficient production of uniform emulsions and dispersions, relevant to diverse fields from pharmaceutical Active Ingredient controlled release particles to Fast Moving Consumer Goods. A novel highly robust single‐pass continuous phase crossflow system has been developed providing...

These are the visual observations of the unflocculated, or loosely aggregating solids sedimentations. The flocculated experiments are provided separately.

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Sedimentation in hindered settling is simple, and it may give a reliable result for average particle size without the need for expensive and complicated instrumental equipment. Observing the settling interface is all that is needed, and a good understanding of what is going on.

Membrane Emulsification, from laboratory study to commercial production based on fundamental engineering design principles and validated scale-up models.

The minerals calcium carbonate and talc were filtered under various conditions of filtrate flow rate and suspension concentration, using constant rate conditions with the aid of a peristaltic pump to draw the filtrate. Cake concentrations of between 0.41 and 0.53 v/v for calcium carbonate and 0.19 and 0.26 v/v for talc were recorded. The mean sizes...

Cellulose recalcitrance is one of the major barriers in converting renewable biomass to biofuels or useful chemicals. A pretreatment reactor that forms a dielectric barrier discharge plasma at the gas-liquid interface of the microbubbles has been developed and tested to pretreat α-cellulose. Modulation of the plasma discharge provided control over...

The mode of application of oscillation, axial or azimuthal, did not influence filtration performance, when filtering a calcite mineral with a d32 value of 2.7 µm. The equilibrium flux and deposit thickness correlated with shear stress, regardless of: filter type (metal slotted surface filter or homogeneous sintered filter); and mode of oscillation....

Nowadays, oil–in–water emulsion has become an important topic in petroleum industry, which produces oil–inwater emulsion in the recovery of crude oil. Oil–in–water emulsion produced in crude oil recovery causes problems at different stages of the production in the petroleum industry. Recently, microfiltration has been applied in the separation of o...

Microcrystals of piroxicam (PRX) monohydrate with a narrow size distribution were prepared from acetone/PRX solutions by antisolvent crystallisation via metallic membranes with ordered pore arrays. Crystallisation was achieved by controlled addition of the feed solution through the membrane pores into a well-stirred antisolvent. A complete transfor...

Hydrophobization of metal surfaces is reported based on silanization reactions. The aim was its application to metal porous membranes for the production of water in oil emulsions using a process known as membrane emulsification. A vertical oscillating membrane system was used to carry out drop formation experiments. It is shown that drop size can b...

It is shown that formation of water based droplets in an immiscible (i.e. oil) continuous phase can be achieved using a hydrophilic porous metal membrane without prior hydrophobic treatment of the membrane surface. This avoids the need for “health and safety approval” of typical hydrophobic treatments for the membrane, which often use chemicals inc...

The feasibility of an integrated continuous biphasic oxidation process was studied, incorporating (i) electrochemical generation of an oxidant, (ii) membrane emulsification and an Oscillatory Flow Reactor (OFR) to facilitate mass-transfer in a biphasic reaction system and (iii) product extraction to enable regeneration of the oxidant. The biphasic,...

Hydrothermal carbonization (HTC) is a thermochemical process used to convert wet biomass into a carbon-rich material with a high calorific value, which is referred to as 'hydrochar.' HTC is typically conducted at moderate temperatures (160-250oC) under saturated pressures and for treatment times ranging from several minutes to hours. Although HTC h...

The hydrothermal carbonisation (HTC) conversion of wet wastes, such as sewage sludge, generates a carbon-rich material (called ‘hydrochar’), and an aqueous fraction with a small release of gas. The liquid fraction is high in soluble chemical oxygen demand, from 10 to 50 g/L, and could not be discharged to the natural environment without treatment....

Membrane Emulsification was used to encapsulate yeast cells and form microparticles. W/O emulsions were produced using a Dispersion Cell; the aqueous phase consisted of gelatin/chitosan, or pure gelatin solution, containing yeast cells, the continuous phase was 2 wt.% of SPAN 80 in kerosene. Varying the dispersed phase flux (from 70 to 350 L h⁻¹ m⁻...

Well-known analytical equations for predicting permeability are generally reported to overestimate this important property of porous media. In this work, more robust models developed from statistical (MVR) and Artificial Neural Network (ANN) methods utilized additional particle characteristics (‘fines ratio’ (x50/x10) and particle shape) that are n...

Rapamycin loaded polycaprolactone nanoparticles (RAPA-PCL NPs) with a low polydispersity index of 0.006-0.073 were produced by anti-solvent precipitation using a ringed stainless steel membrane with 10-μm diameter laser-drilled pores. The organic phase composed of 6 g L⁻¹ of PCL and 0.6−3.0 g L⁻¹ of RAPA in acetone was injected through the membrane...

Biodegradable poly(ε-caprolactone) (PCL) drug-carrier nanoparticles (NPs) were produced by rapid membrane micromixing combined with nanoprecipitation in a stirred cell employing novel membrane dispersion. The organic phase composed of 0.1−0.6 wt% PCL dissolved in tetrahydrofuran was injected into the aqueous phase (Mili-Q water or 0.2−1 wt% poly(vi...

The Dispersion Cell membrane emulsification technique was used for the production of w/o emulsions with controlled droplet size and narrow size distribution. The influence of the operating parameters of the process was investigated. Varying the dispersed phase flux (10–1250 L h−1 m−2) and the shear stress (2–59 Pa), droplets between 30 and 280 μm w...

Hydrothermal carbonisation (HTC) has the capability to convert wet biomass such as sewage sludge to a lignite-like renewable solid fuel of high calorific value. However, to date assessment of the energy efficiency of the HTC process has not been fully investigated. In this work, mass and energy balances of semi-continuous HTC of faecal waste conduc...

A novel membrane emulsification system is reported consisting of a tubular metal membrane, periodically azimuthally (tangentially) oscillated with frequencies up to 50 Hz and 7 mm displacement in a gently cross flowing continuous phase. A CFD analysis showed consistent axial shear at the membrane surface, which became negligible at distances from t...

Eco-friendly O/W emulsions were produced by membrane emulsification using nickel membrane consisting of hexagonal arrays of cylindrical pores of 10 or 20 μm diameter and 200 μm spacing. The dispersed phase was a mixture of N,N-dimethyldecanamide (AMD-10TM) and d-limonene containing 0-35 wt% AMD-10TM in the dispersed phase and the continuous aqueous...

The effect of reaction temperature and time on the filterability of slurries of primary sewage sludge (PSS) and synthetic faeces (SF) following hydrothermal carbonization (HTC) was investigated and optimized using response surface methodology (RSM). Filterability was shown to improve as the treatment temperature and reaction time at which the solid...

Hydrothermal carbonisation of primary sewage sludge was carried out using a batch reactor. The effect of temperature and reaction time on the characteristics of solid (hydrochar), liquid and gas products, and the conditions leading to optimal hydrochar characteristics were investigated. The amount of carbon retained in hydrochars decreased as tempe...

Food-grade water-in-oil-in-water (W/O/W) multiple emulsions with a volume median diameter of outer droplets of 50-210 mu m were produced by injecting a water-in-oil (W/O) emulsion at the flux of 30 L m(-2) h(-1) through a 10-mu m pore electroplated nickel membrane oscillating at 10-90 Hz frequency and 0.1-5 mm amplitude in 2 wt% aqueous Tween(R) 20...

Size distribution of crude oil drops in the permeate has been predicted using the ‘linear fit’ approach with, and without oscillating the membrane. Without membrane oscillation (without shear rate), static and drag forces are taken into account and their balance is assumed as 100% cut-off or rejection point. With the membrane oscillation, ‘inertial...

Decomposition kinetics of primary sewage sludge (PSS) and synthetic faeces (SF), of various moisture contents, were investigated over different reaction times and temperatures using a hydrothermal batch reactor. Solid decomposition of PSS and SF was first-order with activation energies of 70 and 78 kJ/mol, and pre-exponential factors of 4.0 × 106 a...

A novel membrane contactor method was used to produce size-controlled poly(ethylene glycol)-b-polycaprolactone (PEG-PCL) copolymer micelles composed of diblock copolymers with different average molecular weights, Mn (9200 or 10400 Da) and hydrophilic fractions, f (0.67 or 0.59). By injecting 570 l m-2 h-1 of the organic phase (a 1 mg ml-1 solution...

In the flow of a deforming drop through a slotted pore, such as during the microfiltration of oil drops suspended in water, the mechanism for the convection of the oil drops is liquid drag caused by permeate flow through the filter. If the slot is designed to have a converging inlet section then it is possible to estimate the force on the drop from...

A diblock copolymer constituting of a poly(ethylene glycol) (PEG) and a polycaprolactone (PCL) segment, linked with a pH-sensitive hydrazone bond (Hyd), was synthesized. Micelles formed from this copolymer, offer the advantage of encapsulating hydrophobic drugs without the need for conjugation sites. All synthesized polymers were characterised usin...

Liposomes with a mean size of 59-308 nm suitable for pulmonary drug delivery were prepared by the ethanol injection method using nickel microengineered flat disc membranes with a uniform pore size of 5-40 [small mu ]m and a pore spacing of 80 or 200 [small mu ]m. An ethanolic phase containing 20-50 mg/ml phospholipid (1-palmitoyl-2-oleoyl-sn-glycer...

The permeability of particulate colloidal titanium dioxide, P25, was investigated during sedimentation, permeation and filtration when suspended in water at a consistent ionic strength similar to tap water. Happel’s cell model of permeability was used to determine the apparent particle size during these processes, and compared with the size of part...