Solution Interface Research Articles

Polyethylenimine-Based Electrochemical Sensor for the Determination of Caffeic Acid in Aromatic Herbs

An electrochemical sensor based on carbon paste modified with polyethyleneimine was developed and employed for the determination of caffeic acid in aromatic herbs. The sensor was prepared by mixing polyethylenimine (1.5% v/v), graphite powder, and mineral oil. The polyethylenimine-based electrode showed an enhancement of charge transfer at the electrode–solution interface and a higher current intensity for the electrochemical reaction of caffeic acid, in comparison to the unmodified electrode. The calibration plot of caffeic acid constructed in 0.1 mol L−1 acetate buffer (pH 5.0) by square wave voltammetry was linear in the range of 1.25 to 19.9 μmol L−1 with a limit of detection of 0.13 μmol L−1, respectively. Finally, the proposed sensor was employed to monitor the caffeic acid with accuracy in dried Thymus vulgaris and Salvia officinalis samples, with recovery results from 93 to 105%.

Chemical and Electrochemical Study of Effect of Soluble Sulfonated Polystyrene on Mild Steel Interface in Hydrochloric Acid Solution

The author has focused on the corrosive effect of 0.14% carbon steel in the occurrence of several amounts of soluble Sulfonated Polystyrene (SPS) and was found to be best efficient on soft iron exterior at 100ppm concentration in 0.5M hydrochloric acid assortment at 298K heat during 3h of time in this paper. The examination was performed by studying the weight loss of mild steel by varying different parameters like mixture concentration, time, and solution temperature. The efficiency of SPS was observed to rise with an increase of 91.90% of an inhibitor in the acid solution. The mechanism of physical adsorption was studied to the initiation and permitted dynamics for the reaction of altitude and extracted taking place towards the exterior of the iron sample in endothermic, impulsive and dependable through the Langmuir isotherm adsorption. Anodic and cathodic both type of nature of soluble SPS was studied using the potentiodynamic polarization method. The AFM analysis was used to do the surface and protective film analysis and under varied settings, SPS polymer inhibitor proven to be more suited for iron metal exterior.

Development of saga (Abrus precatorius) seed extract as a green corrosion inhibitor in API 5l Grade B under 1m HCL solutions

The critical role of newly green corrosion inhibitors shows the disruption of cathodic and anodic reactions at the metals and solution interface. The object of this study is the development of Saga as a corrosion inhibitor to mitigate the effect of corrosive HCl 1M оn mild steel. The inhibitor was extracted using methanol to prepare various concentrations. Fourier transform infrared (FTIR) spectroscopy was used to determine the functional group of the inhibitor. The electrochemical impedance spectroscopy aided by the potentiodynamic polarization was utilized to evaluate the inhibitor’s effectiveness. Optical emission spectroscopy (OES) was implemented to determine the percentage of elements in mild steel. Based on the FTIR results, C=O, -OH, C=C, benzene, and C-O are accountable for the inhibitor to donate its lone pair of an electron to the 3-d orbital of iron metal. Increasing the inhibitor concentration decreases the capacitive double layer to elevate the inhibitor resistance. The higher inhibitor resistance of 29.33 Ω cm-1 increases as the concentration increases due to the depression of Cdl 420.16 µF cm2 at 10 ml inhibitor solution. Parallelly, it increases the inhibition efficiency at 65.58 %, slightly lower than the PP measurement of nearly 88 %. The higher value of adsorption/desorption constant, Kads, at 2.9 L mol-1 shows the strength of the inhibitor, which lowers the value of Gibbs free energy (ΔGads). The Saga inhibitor is considered a chemisorption inhibitor ΔGads –36.87 kJ/mol. The value demonstrates the formation of dative covalent bonding, which promotes the transferred electron from the inhibitor to the substrate. On the other hand, the Saga inhibitor abides by the Langmuir adsorption isotherm as the R2 value is 0.99.

Insight into leaching of rare earth and aluminum from ion adsorption type rare earth ore: Adsorption and desorption

Clay minerals are inferred to be the primary host materials for ion-exchangeable rare earth in ion adsorption type rare earth ore (IAREO). During the rare earth leaching process, the adsorption and desorption reactions of the cations controlling the leaching process continue to occur at the clay minerals-leaching agent solution interface. In order to understand the leaching mechanism and behavior of rare earth and co-leached aluminum, adsorption, competitive adsorption, and desorption experiments were carried out using kaolin as a typical clay mineral. The powerful electrostatic attraction and concentration driving forces facilitate the adsorption of cations. The adsorption ability and competitive adsorption ability of cations depend on their charge, hydration radius, and hydrolysis properties, and decrease in the order of La3+, Y3+, Al3+, Mg2+, and NH4+. The desorption of rare earth and aluminum is positively affected by the concentration-driving force exerted by high concentrations of Mg2+ and NH4+, with the order of the desorption ability being opposite to the adsorption ability. However, unspecified interactions between clay mineral particles enhanced by high-concentration desorbents, especially by Mg2+ than NH4+, will adversely affect desorption reactions, which result in lower desorption efficiencies of rare earth and aluminum obtained with magnesium sulfate compared to those obtained with ammonium sulfate at high concentrations. Solid-phase Al(OH)3 generated at a high peak aluminum concentration leads to a considerably delayed aluminum efflux, thereby partially separating the rare earth from aluminum during the actual column leaching process. To advance the mining technology of IAREO by selectively improving the rare earth leaching efficiency with minimal leaching agent consumption, higher charged cations with concentrations limited to suitable levels should be preferred as leaching agents.

A dual-scale analysis of mass transfer enhancement in liquid desiccant system for indoor VOCs removal by adding surfactant

Indoor volatile organic compounds (VOCs) pollution control is a major challenge facing the healthy development of people. Liquid dehumidification is expected to be a potential way for VOCs removal. However, the poor mass transfer ability for some hydrophobic VOCs in liquid desiccant (LD) system results in a lower removal performance. Therefore, a dual-scale perspective is proposed to enhance VOCs transfer in this study. It includes micro material property for VOCs transfer at solution interface, and macro system model for heat-moisture-VOCs transfer in LD system. The micro and macro sub-perspectives are combined via key information exchange. Moreover, surfactant is firstly introduced into LD system to enhance VOCs transfer from dual-scale perspective. The surfactant can effectively improve the solubility of hydrophobic VOCs in LD and enhance their mass transfer at solution interface. Through experiment and simulation, the influences of micro material properties and macro working parameters on VOCs transfer characteristic are investigated considering air dehumidification requirements. Using the proposed dual-scale perspective, a new LD is designed. Thus, the VOCs transfer ability at micro interface and macro system are improved by 19.24% and 16.67%, respectively. It is found that the enhanced VOCs transfer ability is co-determined by micro material properties and macro working parameters. In a way, the proposed approach can realize the dual-scale co-design from “micro interface - macro system”. Entirety analysis of the VOCs transfer characteristics in LD system is feasible with this methodology.

Vanadate Retention by Iron and Manganese Oxides.

Anthropogenic emissions of vanadium (V) into terrestrial and aquatic surface systems now match those of geogenic processes, and yet, the geochemistry of vanadium is poorly described in comparison to other comparable contaminants like arsenic. In oxic systems, V is present as an oxyanion with a +5 formal charge on the V center, typically described as HxVO4(3–x)–, but also here as V(V). Iron (Fe) and manganese (Mn) (oxy)hydroxides represent key mineral phases in the cycling of V(V) at the solid–solution interface, and yet, fundamental descriptions of these surface-processes are not available. Here, we utilize extended X-ray absorption fine structure (EXAFS) and thermodynamic calculations to compare the surface complexation of V(V) by the common Fe and Mn mineral phases ferrihydrite, hematite, goethite, birnessite, and pyrolusite at pH 7. Inner-sphere V(V) complexes were detected on all phases, with mononuclear V(V) species dominating the adsorbed species distribution. Our results demonstrate that V(V) adsorption is exergonic for a variety of surfaces with differing amounts of terminal −OH groups and metal–O bond saturations, implicating the conjunctive role of varied mineral surfaces in controlling the mobility and fate of V(V) in terrestrial and aquatic systems.

In vitro investigation of protein assembly by combined microscopy and infrared spectroscopy at the nanometer scale

The nanoscale structure and dynamics of proteins on surfaces has been extensively studied using various imaging techniques, such as transmission electron microscopy and atomic force microscopy (AFM) in liquid environments. These powerful imaging techniques, however, can potentially damage or perturb delicate biological material and do not provide chemical information, which prevents a fundamental understanding of the dynamic processes underlying their evolution under physiological conditions. Here, we use a platform developed in our laboratory that enables acquisition of infrared (IR) spectroscopy and AFM images of biological material in physiological liquids with nanometer resolution in a cell closed by atomically thin graphene membranes transparent to IR photons. In this work, we studied the self-assembly process of S-layer proteins at the graphene-aqueous solution interface. The graphene acts also as the membrane separating the solution containing the proteins and Ca2+ ions from the AFM tip, thus eliminating sample damage and contamination effects. The formation of S-layer protein lattices and their structural evolution was monitored by AFM and by recording the amide I and II IR absorption bands, which reveal the noncovalent interaction between proteins and their response to the environment, including ionic strength and solvation. Our measurement platform opens unique opportunities to study biological material and soft materials in general.

Half-cell and noise voltages at a metal-electrode and dilute solution interface

The detection of bioelectric signals is usually based on an electrode-skin contact that is often mediated by a layer of conductive gel. This interface produces a DC voltage (half-cell potential) and a random noise voltage whose relationship is not well known. The first may cause amplifier saturation and the second posits a limit to the detection of small signals. This work investigates the mechanisms of generation of these two voltages in the simpler case of a metal-electrolyte junction and finds a theoretical expression for both, under a few simplifying hypotheses. An expression is found that relates the two voltages to the ionic concentration and to the parameters defining the dynamics of the adsorption–desorption phenomena taking place at the interface. A relationship is found between the two voltages that is in qualitative agreement with experimental findings reported in the literature. This theoretical background provides a basis for further investigation of the metal-gel and of the gel-skin interfaces not addressed in this work.

The study of the interactions of malonic acid ions with the hydroxyapatite surface in liquid

• Adsorption is described by the multiexponantiate model. • The last stage of the adsorption kinetics indicates the process of precipitation of a new phase. • Adsorption of malonic acid is best described by the Redlich-Paterson isotherm model. • The presence of adsorbed malonate ions causes an increase in the concentration of acid groups on the hydroxyapatite surface. Adsorption of malonic acid at the hydroxyapatite/aqueous NaCl solution interface based on the measurements of adsorption / desorption kinetics and adsorption as a function of pH was presented. The adsorption of malonate ions was determined from the loss of ion concentration in the solution as measured by the radioisotope using 14C labeled malonic acid. The adsorption measurements were supplemented with electrophoretic zeta potential as well as and FTIR measurements. The kinetics of adsorption from a solution with an initial concentration of 1 mmol/dm3 of malonic acid proceeds in three stages, in the last stage there was observed a rapid increase in adsorption, which proves the precipitation of a new phase by the malonate ions. The presence of this phase was confirmed by examining the crystallinity of the hydroxyapatite sample conditioned in a malonic acid solution by the method of Landi et al. on the basis of XRD patterns and measurements of particle distribution using the light scattering method.

Effects of interdiffusion on shear response of semi-coherent {111} interfaces in Ni/Cu

Intermixing of chemical species as a result of interdiffusion during the manufacturing of metallic nanolaminates leads to diffuse interface structures which have distinct properties compared to corresponding atomically sharp interfaces. The effect of interdiffusion-induced changes to the interface structure on interface shear strength is complex due to the presence of solute atoms and a reduced misfit dislocation density. The shear responses of {111} Cu/Ni nanolaminate interfaces with varying levels of interdiffusion are studied using atomistic methods to elucidate the effect of interface structure changes on shear deformation mechanisms. Models with diffuse interfaces exhibit improved interface shear strength relative to the atomically sharp case; however, shear strength does not increase monotonically with solute concentration. The distribution of maximum changes in energy per misfit node and non-uniform misfit node displacements, filtered using microrotation vector analysis, suggest heterogeneous interface resistance to sliding. No strong correlation is found between solute concentration near misfit node centroids and misfit node displacements, indicating the importance of the longer-range misfit dislocation structure. Increased activation of misfit dislocation glide is associated with larger solute concentrations as a result of increased misfit node displacements. Analysis of change in energy during the shear deformation process, however, reveals that interface sliding is dominated by the misfit node behavior. These findings highlight the importance of modeling realistic diffuse interface structures and emphasize the competing effects of solute concentration and interface misfit dislocation density.

Ion and Particle Size Effects on the Surface Reactivity of Anatase Nanoparticle–Aqueous Electrolyte Interfaces: Experimental, Density Functional Theory, and Surface Complexation Modeling Studies

At the nanoscale, particle size affects the surface reactivity of anatase–water interfaces. Here, we investigate the effect of electrolyte media and particle size on the primary charging behavior of anatase nanoparticles. Macroscopic experiments, potentiometric titrations, were used to quantitatively evaluate surface charge of a suite of monodisperse nanometer sized (4, 20, and 40 nm) anatase samples in five aqueous electrolyte solutions. The electrolyte media included alkaline chloride solutions (LiCl, NaCl, KCl, and RCl) and Na-Trifluoromethanesulfonate (NaTr). Titrations were completed at 25 °C, as a function of pH (3–11) and ionic strength (from 0.005 to 0.3 m). At the molecular scale, density functional theory (DFT) simulations were used to evaluate the most stable cation surface species on the predominant (101) anatase surface. In all electrolyte media, primary charging increased with increasing particle size. At high ionic strength, the development of negative surface charge followed reverse lyotropic behavior: charge density increased in the order RbCl < KCl < NaCl < LiCl. Positive surface charge was greater in NaCl than in NaTr media. From the DFT simulations, all cations formed inner-sphere surface species, but the most stable coordination geometry varied. The specific inner-sphere adsorption geometries are dependent on the ionic radius. The experimental data were described using surface complexation modeling (SCM), constrained by the DFT results. The SCM used the charge distribution (CD) and multisite (MUSIC) models, with a two-layer (inner- and outer-Helmholtz planes) description of the electric double layer. Subtle charging differences between the smallest and larger anatase particles were the same in each electrolyte media. These results further our understanding of solid–aqueous solution interface reactivity of nanoparticles.

Comment on "Liquid-Gas Interface of Iron Aqueous Solutions and Fenton Reagents".

A recent Letter in this Journal (Gladich et al. J. Phys. Chem. Lett. 13, 2994-3001) reported that photoelectron spectroscopy could not detect any products on the surface of aqueous Fe2+ jets dosed with gaseous hydrogen peroxide. The Letter however concluded that Fe(aq)2+ ions react with H2O2(g) at the water-vapor interface to produce the same Fe3+ + HO• products as their reaction with H2O2(aq) in bulk water. We argue that this conclusion is untenable because nothing can be asserted about undetected species.

Reply to "Comment on 'Liquid-Gas Interface of Iron Aqueous Solutions and Fenton Reagents'".

A Viewpoint regarding our recently published Letter in this Journal (Gladich et al. J. Phys. Chem. Lett. 13, 2994-3001) criticizes some of our conclusions. While a sentence in the abstract and one in the conclusion of the Letter might seem too conclusive, in the body text we objectively discussed experimental results obtained by means of three different surface-/interface-sensitive spectroscopies. Such results were supported by theoretical calculations. The aim of our work was not to criticize past results. On the contrary, we critically discussed our data taking into account those obtained in the past.

Corrosion prevention of mild steel in acidic medium by 2-Pyrrolidin-1-yl-1,3-thiazole-5-carboxylic acid: Theoretical and experimental approach

The inhibition efficiency of 2-Pyrrolidin-1-yl-1,3-thiazole-5-carboxylic acid (PTCA) against mild steel (MS) corrosion was investigated in acidic solution by using quantum chemical calculations based on Density Functional Theory (DFT) method and electrochemical measurements. The electrochemical impedance spectroscopy (EIS), potentiodynamic, potential zero charge (pzc) analysis and electrochemical noise (EN) measurements at various concentrations (from 0.1 to 10 mM) and immersion times were utilized in experimental part. The surface analysis was achieved scanning electron microscope (SEM) and contact angle measurements in the absence and presence of 10 mM PTCA. According to DFT results, PTCA exhibited 3.737 eV band gap and 8.130 Debye dipole moment which were a signal of potentially convenient corrosion inhibitor properties. PTCA has a remarkable corrosion inhibition capability to mild steel, which inhibited both anodic and cathodic corrosion rates, relying on it's physically adsorption on the metal solution interface and protection ability was increased with increasing PTCA concentration. The obtained adsorption equilibrium constant was 11.11 × 103 M-1 and calculated standard free energy of adsorption was −33.03 kJ mol−1. The determined activation energy values were 55.58 kJ mol−1 and 96.86 kJ mol−1 in 0.5 M HCl in the absence and presence of 10 mM PTCA, respectively. PTCA demonstrated a strong inhibition efficiency of 98.3%, after 168 h immersion, according to the EIS results. As a consequently, we recommend that PTCA is a convenient inhibitor in 0.1 M HCl for mild steel protection against corrosion.

Gas generation due to photocatalysis as a method to reduce the resistance force in the process of motors motion at the air–liquid interface

HypothesisThe problem of the development of miniature motors able to move on the air–liquid interface at low Reynolds numbers is a crucial challenge due to dominating role of viscous force. To solve this problem the chemical generation of gas can be used. Generated gas pushes liquid out from the surfer surface, so the resistance force is reduced. ExperimentsSurfer composed of TiO2 nanoparticles and ferromagnetic cobalt microparticles moves at the interface of an aqueous solution of hydrogen peroxide under the action of magnetic force. After irradiation with UV or visible light, the gas cavern is formed at the surfer surface due to photo-catalytic decomposition of hydrogen peroxide. As a result, the area of surfer contact with liquid is reduced. FindingsThe resistance force acting on the surfer is reduced due to the liquid pushing out from the surfer surface. This effect is strengthened with the increase in the intensity of gas generation. The resistance force is increased when increasing the liquid viscosity or using a surfactant. The proposed method allows control of the velocity of the motors in a rather wide range by changing the gradient of the magnetic field and parameters of light.

In Operando Visualization and Dynamic Manipulation of Electrochemical Processes at the Electrode–Solution Interface

Revealing the dynamic processes at the electrode-solution interface is imperative for understanding electrochemical phenomena. Most techniques have been developed to sense the electrode surface changes at the nanoscale, but provide limited information on potential-induced interfacial ion redistribution at the mesoscale. Herein, we present an in operando visualization method utilizing a microfabricated electrochemical cell combined with a laser scanning confocal microscope to observe high-resolution and fast-response interfacial processes. We report potential-induced formation and transformation of the Nernst diffusion layer, demonstrating that pulsed voltage dynamically perturbs the interface and promotes ion diffusion. This provides an additional insight into developing a dynamic manipulation method to control the electrochemical process. Our novel visualization method can easily be applied to monitor different ionic behaviors in electrochemical reactions at the mesoscale.

Characterizing Recast Nafion® Film Electrode Interface Diffusion and Kinetics in a Non-Aqueous System

The effect of recast Nafion® films on platinum working electrodes in acetonitrile will be characterized by cyclic voltammetry and rotating disk voltammetry. Until now, the behavior of recast Nafion® in a non-aqueous system has not been reported in this way. The behavior of recast Nafion® films in acetonitrile has been anecdotally observed to be different from the behavior in aqueous solutions, which have also been comprehensively studied1,2. The reversible redox couple of Tris(2,2′-bipyridine)ruthenium(II) hexafluorophosphate, Ru(bpy)3 2 ++, in an acetonitrile electrolyte solution will be compared between a bare platinum working electrode and a recast Nafion® film coated platinum working electrode by cyclic voltammetry. In cyclic voltammetry the convective mass transport of the species is limited only to the diffusion at the stationary electrode interface. In rotating the working electrode (RDE) the limitation on mass transport is extended beyond the stationary diffusion behavior. The current is dependent on and limited by the mass transport of the species to the electrode interface where it can undergo redox, the limiting current of both a bare platinum working electrode system and of a recast Nafion® film coated platinum working electrode will be observed by changing the rotation rate of the RDE. The diffusion interface of the electrode inside an acetonitrile solution of Ru(bpy)3 2 + and an electrolyte will be determined by rotating disk voltammetry at a bare platinum working electrode and at a recast Nafion® film coated platinum working electrode. The film solution interface thickness will be reported along with the effect on the diffusion of the interface between bare and recast Nafion® coated platinum working electrodes.1. S. K. Zecevic et al 1997 J. Electrochem. Soc. 144 29732. T. A. Zowodzinski, S. Gottesfeld et al 1997 Advances in Electrochemical Sciences and Engineering

Molecular dynamics simulation of impurity effects near the NaCl interface during the initial rapid stages of growth

For salt processing, it is necessary to understand impurity incorporation into NaCl crystals at the molecular level. In this study, molecular dynamics (MD) simulations of NaCl crystal growth were performed to analyze the solution structure near the interface between a NaCl crystal and NaCl–NaBr or NaCl–NaI solutions and to calculate the dehydration energy in the presence of impurities (Br− and I−). Furthermore, the adsorption mechanism of solute ions onto the NaCl surface during the initial growth stage of batch crystallization was investigated. Both Br− and I− were found to decrease the adsorption rate, but the impurity effects of these ions were different. Moreover, the adsorption rate in the presence of Br− was faster than that in the presence of I−. In the presence of Br−, the adsorption rate was decreased by the rate-limiting effect of the growth rate of Br−. By contrast, in the presence of I−, the adsorption rate was reduced by the abundance of I− near the interface, as the supply of Cl− near the interface was limited by electrostatic effects. In addition, the local concentration of impurities (Br− and I−) near the crystal–solution interface was higher than the saturated concentration. This difference from the bulk composition suggests that impurities may even crystallize at unsaturated concentrations.

Mechanisms of ionic liquids on the enhancement of interfacial transport of lithium ions in crown ether system

Lithium and lithium isotopes are important for clean energy development. By introducing ionic liquid, the extraction performance of crown ethers for lithium ions can be significantly improved. However, the enhancement mechanism of ionic liquids in the system is not clear, which directly limits the selection of suitable ionic liquids for various applications. In this work, the synergy mechanisms of different ionic liquids with crown ether during the extraction process were investigated by molecular dynamics simulations and verified by experimental results. There were two molecular mechanisms to capture lithium ions for ionic liquids in the crown ether system: co-extraction and assisted extraction. It was generally considered that the cation exchange mechanism was responsible for the extraction of lithium ions in the crown ether-ionic liquids system. Here, a novel perspective was revealed that one [Li·H2O]+ complexed with crown ether and then the chelate cation coordinated with the anion of the ionic liquid to form a neutral molecule based on the simulation of the whole extraction process with molecular dynamics that favored the transport of Li+ from aqueous solution to organic solution. In the system without ionic liquids, Li+-crown ether chelates were distributed only at the interface and did not enter the organic phase which is supported by very low extraction efficiency. It was attributed that charge equilibrium cannot be achieved when Li+-crown ether chelates enter into organic solution in the absence of ionic liquids. Overall, a new insight into the interfacial transport mechanisms of lithium ions was proposed, in which the anion of ionic liquids played a key role in capturing lithium ions at the interface of aqueous solution and organic solution.

Oxygen Nanobubbles for Lake Restoration—Where Are We at? A Review of a New-Generation Approach to Managing Lake Eutrophication

Nutrient enrichment of lakes from anthropogenic activities is a significant and increasing issue globally, impairing the health, biodiversity and service provisioning from lakes, with impacts on cultural, recreational, economic and aesthetic values. Internal nutrient loads from lakebed sediment releases are a primary cause of lake eutrophication and have necessitated geoengineering methods to mitigate releases and speed up recovery from eutrophication. Our objective in this review was to evaluate the use of oxygen nanobubbles as a geoengineering technology to remediate low oxygen conditions at the lake sediment/water interface, as a precursor to alleviating eutrophication linked to high internal nutrient loads. Oxygen nanobubbles (NBs) are bubbles < 1000 nm formed at the interface of solid surfaces and aqueous solutions. These bubbles have higher density than water, persist for longer and facilitate greater oxygen solubility than larger bubbles. Methods have been developed to enable NB formation at the surface of carrier materials, which are then used in conjunction with modified local soils (MLSs), to ‘floc, lock and oxygenate’ to strip nutrients from the water column, locking them in lakebed sediments and oxygenating the sediments to prevent re-release of nutrients. Most studies of NBs for lake restoration have thus far only demonstrated their potential for this purpose, using short-term, small-scale core incubations conducted mainly in laboratory settings. Work is required to (1) address scalability, including procurement and cost, (2) extend laboratory incubation studies to large outdoor enclosures and pond/lake trials, (3) examine longevity of the effects in the natural environment, including potential for MLSs to smother benthos and/or have toxic effects, and (4) extend to a range of lake environments and MLS types. Legal, cultural and social acceptance of the technology is another prerequisite of applications in the natural environment and requires individualised analysis. Until these issues are addressed in a systematic way that addresses scalability and recommends suitable carrier materials and MLSs, NBs may continue to remain largely untried as a geoengineering method to address lake eutrophication.