Ponisseril Somasundaran

Columbia University | CU · Department of Earth and Environmental Engineering

Citation: Hussien S, Patra P, Somasundaran P, et al. (2018) Assessment of 'Bacterial (Acidic)-Leaching' of Rare Earth Elements from a Phosphate Ore. Advances Environ Stud 2(2):91-97 Abstract Bioleaching methods are environmentally benign and economical options for extraction of rare earth elements (REEs) from low grade REE ores. We conducted shake-...

We have developed a novel metal-free highly robust recyclable electrosorbent for removal Pb(II) from water. It is based on a cost-efficient and biocompatible conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) which is synthesized through a facile green chemistry route. This electrosorbent demonstrates superior adsorption-desorption propert...

An earlier study (Part I) indicated that Cu²⁺ ion suppresses while Fe³⁺ ion promotes xanthate decomposition into CS2. The main factor responsible for the disparate effects was proposed to be the differences in interactions between xanthate and metal ions in solution. UV–vis and FTIR spectrometers were used to examine the products of such interactio...

To separate siderite from carbonate-bearing iron ore efficiently, specific adsorption configurations and effective species were investigated to compare the adsorption differences of sodium oleate (NaOL) on siderite and hematite surfaces. The species were analysed in neutral conditions, under which the direct flotation of siderite from hematite and...

Interactions between polymer and surfactant provide the system a variety of properties that can be readily used by industries to achieve desired features for their products and formulations. Inclusion of a third component to the binary system is expected to present synergistic or antagonistic effects, and also lead to preferred advantages, such as...

Flotation separation and recovery of value minerals from ores containing fibrous silicate minerals are known to be quite challenging. Earlier studies have established that the metallurgical challenges (poor selectivity and recovery, high energy consumption, etc.) arise from the impact of the fibrous minerals (with high aspect ratio) on pulp rheolog...

Electrochemical conversion of the abundant CO 2 to fuels, polymers, drugs, and other materials using renewable energy is one of the most promising approaches that can help deploy this energy and reduce our dependence on fossil fuels. However, the rational development of a viable CO 2 electroreduction system is hampered by a daunting lacunae in the...

The micro-polarity anisotropy behaviour across the aqueous phase of a SDS (sodium dodecyl sulphonate)-hexane reverse micelle (RM) relies on the SDS packing in the oil-water interfacial self-assembled surfactant structure of the RM.

Supported micron-sized molybdenum disulfide (MoS2) has been extensively studied for catalytic synthesis of Higher Alcohols Synthesis (HAS) from synthesis gas (syngas). However, the process is associated with low space-time-yield (STY) and poor selectivity under high temperature (300-325 °C) and high pressure (10-20 MPa) operation, making it unattra...

One of main challenges in developing clinically relevant engineered cartilage is overcoming limited nutrient diffusion due to progressive elaboration of extracellular matrix at the periphery of the construct. Macro-channels have been used to decrease the nutrient path-length; however, the channels become occluded with matrix within weeks in culture...

Nanosized TiO2 (n-TiO2), CeO2 (n-CeO2), and ZnO (n-ZnO) and bulk ZnO were chosen for a 4-h exposure study on a model ammonia oxidizing bacterium, Nitrosomonas europaea. n-ZnO displayed the most serious cytotoxicity while n-TiO2 was the least toxic one. The change of cell morphologies, the retardance of specific oxygen uptake rates and ammonia oxida...

Declining ore grades and quality present multiple challenges to the mineral industry. These include the need for the processing of large tonnages of ores to maintain metal value production, increased energy and water consumption and large amounts of waste, all of which present an economic sustainability challenge. Low grade and poor quality ores te...

Insoluble complexes formed when a cationic polyelectrolyte is neutralized by the oppositely charged surfactant sodium dodecylethersulphate (SDES) in the presence and absence of lauric acid (LA) has been examined directly using NMR spectroscopy and cryo-SEM. Below the SDES critical micelle concentration (CMC') the insoluble complex contains about te...

The effects of fatty acids on oppositely charged polyelectrolyte-surfactant interactions are experimentally investigated. It was observed that dodecanoic (lauric) acid (LA) disrupts the well-established reported interaction between the anionic surfactant sodium dodecylethersulfate (SDES) and the cationic polymer guar modified with grafted hydroxypr...

In beneficiation of Ni ores containing fibrous serpentines in large amounts, flotation pulps exhibit high viscosity, impacting Ni recovery and grade. Fibers entangle in pulp with formation of inter-fiber networks made up of micro floccs that spread across the pulp volume. These networks are sturdy and difficult to disentangle as inter-fiber frictio...

The interaction mechanisms of an oppositely charged polyelectrolyte-surfactant pair and dodecanoic (lauric) acid (LA) were experimentally investigated using a combination of Nuclear Magnetic Resonance (NMR) techniques. It is observed that LA significantly affects the interaction between the anionic surfactant sodium dodecylethersulfate (SDES) and t...

We present a route toward a radical improvement in solar cell efficiency using resonant energy transfer and sensitization of semiconductor metal oxides with a light-harvesting quantum dot (QD)/bacteriorhodopsin (bR) layer designed by protein engineering. The specific aims of our approach are (1) controlled engineering of highly ordered bR/QD comple...

The present work describes the effect of quaternization of silicones as well as the relevant treatment parameter pH on the frictional, morphological and relaxation properties of fabric substrates. Due to their unique surface properties, silicone polymers are extensively used to modify surface properties of various materials, although the effects of...

A general population balance model for the coagulation and flocculation of colloidal suspensions by inorganic electrolytes and polymers is presented. Since the rate of aggregation is determined primarily by the surface forces between colloidal particles, modern theories of surfaces are incorporated into the model. The efficiency of particle collisi...

A unique chemo-enzymatic route to lipopeptides was demonstrated herein that, relative to alternative methods such as SPPS and microbial synthesis, is simple, efficient and scalable. Homo and co-oligopeptides were synthesized from amino acid ethyl esters via protease catalysis in an aqueous media, followed by chemical coupling to fatty acids to gene...

Time-dependent conformational changes of proteins and oil molecules at oil-'protein solution' interface were studied using ATR (Attenuated Total Reflection)-FTIR spectroscopic technique for the case of Bacillus subtilis extracellular proteins (BSEPs) and bovine serum albumin (BSA) in hexane-'protein solution' system. The IR spectra collected on the...

Synopsis Objective Stratum corneum (SC) lipids are known to play an important role in barrier properties of skin by maintaining the optimal hydration levels. The disruption of SC lipids by cleanser surfactants is believed to lead to dry skin damage which can be a precursor to other skin disorders. The purpose of this study is to investigate the eff...

The harsh inflammatory environment associated with injured and arthritic joints represents a major challenge to articular cartilage repair. In this study, we report the effect of cerium oxide nanoparticles, or nanoceria, in modulating development of engineered cartilage and in combating the deleterious effects of interleukin-1α. Nanoceria were foun...

Uniform spreading of oil on solid surfaces is important in many processes where proper lubrication is required and this can be controlled using surfactants. The role of oil-solid interfacial self-assembled surfactant structure (SASS) in oil spreading is examined in this study for the case of hexadecane-surfactant droplet spreading on a flat horizon...

This chapter serves as an initial orientation to the 2010 Gulf of Mexico deepwater horizon (DWH) oil blowout. It presents background information on past oil spills, and gives a brief summary on the Gulf of Mexico marine ecosystems. The chapter gives an overview of offshore petroleum extraction, before discussing the 2010 Deepwater Horizon Spill. It...

Two biosurfactants, surfactin and fatty acyl-glutamate, were produced from genetically-modified strains of Bacillus subtilis on 2% glucose and mineral salts media in shake-flasks and bioreactors. Biosurfactant synthesis ceased when the main carbohydrate source was completely depleted. Surfactin titers were ∼30-fold higher than fatty acyl-glutamate...

Certain non-sulfide gangue minerals are known to have a detrimental impact on flotation performance. When present in large amounts, they can negatively affect recoveries, grades and throughput at current operations, and dictate the viability and economics of a greenfield project. While the problem has been investigated for a long period of time, a...

Fine and ultrafine mineral particles, particularly if, altered mineralogically, can have detrimental effects on selective separation of minerals. Behaviour of altered mineral fines has been investigated in this work by studying the effects of weathered silicate slimes on the selective separation of copper minerals, particularly with focues on effec...

This work addresses the adsorption of two Gemini surfactants at the cyclopentane (CP) hydrate-water interface. The Gemini surfactants investigated here are Dowfax C6L and Dowfax 2A1 that have two anionic head groups and one hydrophobic tail group. The adsorption of these surfactants was quantified using adsorption isotherms and the adsorption isoth...

The effect of a cationic dispersant, polyethyleneimine (PEI) on the co-deposition of 45-55 nm and 1.0 mu m SiC particles with Ni on a rotating disk electrode is investigated. Addition of 500 ppm of PEI into a Watts bath increases the SiC fraction in the nano-composites without affecting the electrodeposition kinetics, however films have undesired p...

Activities of the enzymes, protease subtilisin and horse radish peroxidase (HRP) have been increased 50 and 40%, respectively, in the presence of the nonionic surfactant, alkyl polyglucoside, compared with the activities in buffer alone. This enzyme hyperactivity reaches a peak at 3.0 mm of surfactant. Investigation into the structure of surfactant...

Molybdenum disulfide (MoS2), anchored on a support, is a catalyst of choice to synthesize mixed alcohols, also known as Higher Alcohols Synthesis (HAS) process. However, the process suffers from low space-time-yield (STY) and poor selectivity under high temperature (300o – 325oC) / high pressure (10-20 MPa) operation that makes it unattractive for...

The selection of a surfactant is influenced by its efficacy and environmental impact and may vary depending on the application. There is an increasing demand for biodegradable and non-toxic surfactants in oil spill remediation. Currently, surfactants are mainly derived via chemical synthesis from petroleum-based hydrocarbons. Lipopeptide biosurfact...

A better understanding of interaction with dissolved CO2 is required to rationally design and model the (photo)catalytic and sorption processes on metal (hydr)oxide nanoparticles (NPs) in aqueous media. Using in situ FTIR spectroscopy, we address this problem for rhombohedral 38 nm hematite (α-Fe2O3) nanoparticles as a model. We not only resolve th...

Co-deposition of ceramic particles to enhance properties of electroplated films is difficult to control due to problems involved in dispersing the particles. In this study, co-deposition of 1 mu m SiC particles with nickel from a Watts bath in the presence of a cationic polymer, polyethyleneimine (PEI) as dispersant was investigated. All plating ex...

Clathrate Hydrates are ice-like non-stoichiometric crystalline compounds where water molecules (host molecules) form cages that trap low molecular weight molecules (guest molecules). Clathrate hydrates have attracted lots of attention since the discovery of large reserves of natural gas hydrates in oceanic deposits and permafrost areas because of t...

Froth flotation based on selective separation of the Ni minerals from ores containing large amounts of fibrous serpentines (chrysotile) has been a long lasting challenge. One underlying reason has largely been considered to be slime-coating. The findings from this investigation, on the other hand, show that the pulp rheological behavior of the flot...

This book will describe fundamentals and recent developments in the area of Self-Assembled Supramolecular Architecture and their relevance to the understanding of the functionality of membranes as delivery systems for active ingredients. As the heirarchial architectures determine their performance capabilities, attention will be paid to theoretical...

Interactions between surfactants and water were monitored from the perspective of liquid–vapor interfaces. The surfactants studied were chosen to be the paradigms of the three major types of amphiphilic molecules: the anionic surfactant (e.g. sodium dodecyl sulfate), the cationic surfactant (e.g. dodecyltrimethylammonium chloride), and the nonionic...

This work presents the effect of NaCl on the adsorption of sodium dodecyl sulfate (SDS) at the cyclopentane (CP) hydrate-water interface. The adsorption isotherms and the SDS solubility in NaCl solutions are obtained using liquid-liquid titrations. The solubility data are determined at typical hydrate forming temperatures (274-287K) to ensure that...

Functionalized silicones are a unique class of hybrid materials due to their simultaneous hydrophobic-oleophobic properties, which results in applications in a variety of surface modification techniques. Prior research has shown that changes in surface charge and turbidity of modified silicone emulsions as a function of pH have a marked effect on t...

The 2010 Deepwater Horizon oil release posed the challenges of two types of spill: a familiar spill characterized by buoyant oil, fouling and killing organisms at the sea surface and eventually grounding on and damaging sensitive shoreline habitats, and a novel deepwater spill involving many unknowns. The subsurface retention of oil as finely dispe...

The activated sludge (AS) flocculability markedly improved after the addition of Al(3+) and Fe(3+) compared to Ca(2+) at a concentration of 2 mEq/L. Though the energy barrier decreased about 30% when Ca(2+) was added, the AS flocculability did not improve substantially. This indicates that extended DLVO theory can explain AS flocculation with Al(3+...

This infrared (IR) spectroscopic study addresses surfactant effects on cyclopentane (CP) hydrate-water interfaces by observing both ice-like (3100 cm(-1)) and water-like (3400 cm(-1)) bands in the bonded OH region together with free OH bands. IR spectroscopy of hydrates has not been actively employed due to the overwhelming signal saturation of the...

Flotation beneficiation of ores containing fibrous minerals is highly problematic due to transport of such gangue minerals from pulp to the froth phase. Earlier studies have attributed such transport to the entrainment of fibrous minerals. In this work, this problem is investigated for the case of flotation of ultramafic Ni ore with fibrous serpent...

Gangue minerals can often have severe adverse effects on selective value mineral separation. Such effects can be mediated through a variety of pathways or mechanisms. One popular mechanism is that of ?slime coating? or heterocoagulation, wherein the gangue mineral fines are believed to coat the value mineral surfaces and thereby reduce selectivity...

From the sustainability perspective, the major challenge in mineral processing today is to develop technologies to convert mineral resources into reserves within the energy, water and environmental constraints. Major portions of the many current resources are low quality ores with very complex mineralogy. Conventional technologies are not adequate...

New developments in nanoscience are leading to a much better understanding and control of the natural sensors and actuators. Using its own version of what scientists call nanoengineering, nature transforms abundant and inanimate ingredients into self-generating and self-repairing entities that move, reproduce and possess intelligence. With recent a...

A multiscale stability study of foams stabilized by sodium dodecyl sulfate (SDS), sodium dodecylbenzene sulfonate (SDBS), and sodium polyoxyethylene alkylether sulfate (AES) was conducted, to investigate the relationship of surfactant molecular behavior and interfacial monolayer configuration of foam film to the foam film properties. Molecular dyna...

Surfactant mixtures are widely used in industrial applications due to their favorable synergistic interactions. For instance, anionic and nonionic mixtures are often employed in detergent, personal care, and enhanced oil recovery. It is useful to understand micellization behaviors of such mixtures, as they are important for formulation optimization...

Abiotic and biotic processes catalyzed by ferric (hydr)oxide nanoparticles (NPs) in aquatic media underlie many important nanotechnologies including chemical catalysis, biomedical engineering, remediation of contaminants, and clean renewable energy sources. These processes have been extensively addressed in the past and commonly interpreted within...

Nanotechnology has influenced the direction of research across the sciences, medicine, and engineering. Carbon nanotubes (CNTs) and, more recently, protein nanotubes (PNTs) and protein-inorganic nanocomposites have received considerable attention due to their unique nanostructures that can be utilized as a scaffold to house proteins or create nanow...

The impact of deposition and aggregation on (bio)chemical properties of semiconducting nanoparticles (NPs) is perhaps among the least studied aspects of aquatic chemistry of solids. Employing a combination of in situ FTIR and ex situ X-ray photoelectron spectroscopy (XPS) and using the Mn(II) oxygenation on hematite (α-Fe(2)O(3)) and anatase (TiO(2...

Fibrillar bacterial proteins can be mixed with oil in or on water. The interaction of the proteins at the oil-water interface can result in oil dispersion in water in the form of droplets surrounded by an aggregated protein film. The film may be formed by multiple layers of the fibrillar proteins with water between adjacent protein layers. The prot...

Nature exhibits a variety of remarkable phenomena that are useful but difficult to be imitated in real life. Examples are a "touch me not" plant folding up upon being attacked or microbes depositing on ocean vessels even under hostile conditions. Understanding of mechanisms governing these phenomena can prove powerful for developing new classes of...

IntroductionMathematical ModelResults and DiscussionConclusions References

Adsorption, contact angle and flotation of anionic Atrac and non-ionic ethaloxylated nonylphenol surfactant, and their mixture on apatite and magnetite were studied. The effect of calcium ions and sodium silicate on Atrac adsorp-tion was investigated. The effect of Atrac adsorption on the contact angle data of apatite and magnetite in the presence...

Gas hydrates are non-stoichiometric crystalline compounds in which hydrogen-bonded water cavities encage small molecules such as hydrogen, methane, and cyclopentane (CP). Clathrate hydrates have attracted a lot of attention, because they are not only a potential cause of pipeline blockage in oil and gas industries, but also a promising storage medi...

Application of in situ UV-Vis absorption spectroscopy and ex situ X-ray photoelectron spectroscopy (XPS) makes it possible to resolve the controversies about the electronic properties of hematite (α-Fe(2)O(3)) nanoparticles (NPs) and, on this basis, to rationalize the unusual dependence of aquatic (bio)chemistry of these NPs on NP size. 2-Line ferr...

The complex formed due to the interaction of the amphiphilic betablocker acebutolol with fibrinogen in a buffer solution (50mN glycine, pH of 8.5) has been investigated using a multipronged physicochemical approach. Differential scanning calorimetry measurements of the complexes have shown no reversibility of thermal denaturation as indicated by th...

Coadsorption of electrolyte ions can have a marked influence on the adsorption and hence interfacial reactivity of multicharged ions but has generally been overlooked in previous density functional theory (DFT) studies. The impact of this effect is demonstrated for the DFT-based interpretation of in situ FTIR spectra of the controversial binding fo...

Adsorption, contact angle and flotation of anionic Atrac and non-ionic ethaloxylated nonylphenol surfactant, and their mixture on apatite and magnetite were studied. The effect of calcium ions and sodium silicate on Atrac adsorption was investigated. The effect of Atrac adsorption on the contact angle data of apatite and magnetite in the presence a...

The addition of a small amount of surfactants enhances hydrocarbon enclathration rates without any mechanical agitation, but the role of surfactants has yet to be clarified. This work presents the effect of sodium dodecyl sulfate (SDS) on the water structure around cyclopentane (CP), a sII hydrate former, at the hydrate−water interface. The arrange...

Recent studies have shown that nano-bio interfaces are the most complex and the least understood. Notably, nanotoxicity of these nanoparticles is not even well recognized. In this work, we examined the toxic effects of different nanoparticles on bacteria cells (Nitrosomonas europaea). The four nanoparticles involved are: 25 nm anatase TiO(2), 200 n...

Nanoparticles have been widely applied in many applications due to their specific physical or chemical properties that differ from the bulk counterparts. Because nanoparticles vary significantly in composition and geometry, the comparison of their interaction with another matter is difficult, although in many cases, to characterize and assort nanop...

This work presents the adsorption of an anionic surfactant, sodium dodecyl sulfate (SDS), and a cationic one, dodecyl-trimethylammonium bromide (DTAB), on cyclopentane (CP) hydrates. Adsorption isotherms were obtained by liquid−liquid titrations. Also, the adsorption was qualitatively studied by zeta potential measurements. The isotherm of both SDS...

There has been some efforts in the recent past to study and engineer the interactions between proteins and inorganic nanostructures with the ultimate goal of developing novel, bioinorganic hybrid electronic devices for use in solar cell, ultra-sensitive amperometric sensors and thin film protein-based memory. Of the challenges inherent in integrati...

Interactions of polymers with salts are of primary importance in industry as well as scientific research. In this paper, we focus on the system of poly(acrylic acid) (PAA) in concentrated sodium carbonate aqueous solutions. From the results obtained by density, static/dynamic light scattering, conductivity, and rheometry, the size/shape of single p...

Comb polymers are commonly used as dispersants to stabilize highly concentrated cement suspensions. The effectiveness of such polymeric additives to stabilize these suspensions is determined to a large extent by the amount adsorbed. In this study we investigated the adsorption characteristics of various comb dispersant containing different graft de...

Surfactants find wide commercial use as foaming agents, emulsifiers, and dispersants. Currently, surfactants are produced from petroleum, or from seed oils such as palm or coconut oil. Due to concerns with CO(2) emissions and the need to protect rainforests, there is a growing necessity to manufacture these chemicals using sustainable resources In...

The shape of deposits obtained from drying drops containing colloidal particles matters for technologies such as inkjet printing, microelectronics, and bioassay manufacturing. In this work, the formation of deposits during the drying of nanoliter drops containing colloidal particles is investigated experimentally with microscopy and profilometry, a...

Particulates of 1 to 100 nanometers size are being increasingly used for a variety of clinical and commercial purposes due to their large surface-to-volume ratio and unique physico-chemical, mechanical and electronic properties. While utilizing them for their beneficial functions, it has become vital to heed recent alerts on their toxic biological...

Variations in phosphate ore feed quality pose a serious challenge for their sustained selective flotation. Most critical aspects of the variability of the feed can be attributed to changes in the bulk and surface mineralogy, particle size, degree of liberation of the phosphate minerals in the feed upon grinding. In this regard, similarities and dis...

Coagulation and flocculation are key unit operations in water treatment as efficiency of subsequent clarification and filtration steps is linked critically with the manner, effectiveness, and rate of flocculation [4,5]. Polymers and polyelectrolytes have become favorable flocculation and filtration aids in water treatment due to several reasons [6]...

Unique nanostructures with special properties are exhibited by silicones which are simultaneously hydrophobic and oleophobic. While silicones are utilized in a number of applications, the fundamental reasons behind their special behavior are unknown. This work focuses on understanding the modifications of micro and macro surface properties of mater...