In this study, we report the successful synthesis of Ni-doped ZnS nanocomposite via a green route using ethanolic crude extract of Avena fatua. The as-synthesized nanocomposite was comprehensively characterized using Dynamic light scattering (DLS), Zeta potential, scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and Atomic force microscopy (AFM). These analyses provided detailed insights into the size, morphology, composition, surface properties, and structural characteristics of the nanocomposite. Subsequently, the synthesized nanocomposite was evaluated for their photocatalytic performance against the organic dye Methyl orange. Remarkably, the nanocomposite exhibited rapid and efficient degradation of Methyl orange, achieving 90 % degradation within only 30 min of irradiation under UV light. Moreover, the photocatalyst demonstrated an exceptional hydrogen production rate, reaching 167.73 µmolg-1h-1, which is approximately 4.5 times higher than that of its pristine counterparts. These findings highlight the significant potential of Ni-doped ZnS nanocomposite as highly efficient photocatalysts for wastewater treatment and hydrogen production applications.

Background: Approaches for sustainable, green, and expensive catalyst-free hydrogen production have not been explored extensively. Moreover, during photocatalysis, a lot of material gets wasted due to a lack of proper optimization of the reaction parameters to remove the toxic industrial effluents. Methods: Here in this study, we present the green synthesis of CuO/ZnO nanocomposites from the ethanolic crude extract of Oxystelma esculentum. The synthesized photocomposites were systematically characterized by Fourier transform infrared spectroscopy, zeta potential, x-ray diffraction, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, and x-ray photoelectron spectroscopy. The performed analyses provided useful insights into identifying important functional groups, size, morphology, elemental composition, crystallinity, and defects in the synthesized photocomposites. Significant Findings: After characterization, the nanocomposites were evaluated for photocatalytic sulfasalazine (SSZ) degradation and hydrogen production. The response surface methodology (RSM) was employed to optimize SSZ's photocatalytic degradation. The optimized values of reaction parameters for the photocatalytic degradation of SSZ comprise pH = 4.06, SSZ dose = 47.75 mg/L, CuO/ZnO dose = 44.42 mg, and temperature = 23.60 degrees C. The rates observed in the hydrogen production (1136 mu molh-1g-1) were obtained without costly cocatalyst. The optimized values for hydrogen production include photocatalyst dosage = 50 mg, pH = 7, and time = 5 hours. These features signify the efficient separation of charge carriers between synthesized nanocomposites, resulting in exquisite activities.

Design and eco-friendly fabrication of affordable and sustainable materials for the treatment of wastewater consisting of dyes, antibiotics, and other harmful substances has always been demanding. Untreated wastewater being released from industries imposes serious threats to our ecosystem, seeking convenient approaches to diminish this alarming issue. Here in this work, we synthesized MgO/CuO nanocomposites from a plant extract of Ammi visnaga L. and then employed these nanocomposites for the treatment of organic dye (methylene blue). We characterized the synthesized nanocomposites by dynamic light scattering (DLS), zeta potential, scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), x-ray diffraction (XRD), and X-ray photoelectron microscopy (XPS). DLS presented information about the explicit size of nanocomposites, while the surface charge was examined by zeta potential. XRD provided detailed information about the crystalline behavior and the information regarding surface morphology and size was extracted by SEM, TEM, and AFM. Moreover, the fabricated nanocomposites were used as a photocatalyst in the treatment of methylene blue. The overall catalytic reaction took an hour to complete, and the value of percentage degradation was 98 %. Substantially, a detailed account of the kinetics, rate of reaction, and mechanism is also fostered in the context. The presented study can assist scientists and researchers around the world to reproduce the results and use them to apply them on a broader scale.

Background An organic electrochemical transistor (OECT) is an important device in an area of the art in bioelectronics that can convert ionic and biological inputs into electronic outputs with its aqueous environment. The OECTs use a combination of electronic and ionic charges to leverage the mixed conduction properties of materials within their channel. As bioelectronics applications become popular in OECTs, there is a need to standardize the material channel mixed insulation characteristics, however there is some variation in conditions. This review provides an in-depth formulation of OECTs, including their selection mechanisms, use of organic materials, fabrication methods, and applications to bioelectronics devices. Moreover, it offers a critical assessment of OECT’s research and development in the future. Results The review is organized as follows: First, we provide an overview of the construction and operation of an OECT device in section 2. Next, in section 3, we describe how OECT behavior differs from conventional metal oxide semiconductor field effect transistor (MOSFET), and we discuss how electronic charge transport in the channel by Bernard’s Model. In section 4, we discuss several materials for the transient behavior of OECTs. In section 5, we deal with the recent advances in OECT device fabrication. Then, in section 6, we consider the current applications of OECTs in the fields of biosensing, circuits and logic, neuromorphic computing, and prosthetic and human–machine interfaces. In section 7, we describe limitations concerning the OECT device with expert suggestions to address these limitations. Finally, in section 8, we close the Review with a brief conclusion. Significance A significant advancement has been made in this field through the development of innovative approaches, such as spray coating for uniform channel deposition and screen printing for large-scale production. The full potential of OECTs in revolutionizing bioelectronics and healthcare applications will be realized only through collaborative efforts between researchers, engineers, and industry stakeholders.

Background: Environmentally friendly and sustainable approaches for the removal of hazardous pollutants from wastewater continue to be explored. The present study presents the novel Co-ZnS nanocomposites which were synthesized by the ethanolic crude extract of Oxystelma esculentum and then successfully evaluated towards degradation of Bisphenol A and hydrogen production. The synthesized nanocomposites were systematically characterized by multiple state-of-the-art experimental techniques. Methods: The present study illustrates the green synthesis of Co-doped ZnS nanocomposites and their promising potential for photodegradation of BPA and hydrogen production. The nanocomposite shows an excellent potential for BPA degradation (0.052 min(-1)) and hydrogen evolution (3157.9 mu molh(-1) g(-1)). The detailed optimized analysis of synthesized nanocomposite demonstrates remarkable abilities to degrade organic pollutants by applying a "response surface methodology" model. Significant Findings: The optimized value of the photocatalyst along with optimized parameters presented considerable photocatalytic activity for the degradation of BPA (94.69 %) and the value of hydrogen (3157.9 mu molh(-1) g(-1)). Then, the confirmation of the results (theoretical and experimental yield) was carried out by RSM. The RSM indicated the predicted D % value of 96.84% via the developed model with the optimized conditions of pH = 5.146, BPA dose = [53.448 mg/L], Photocatalyst dose = [58.3058 mg], and temperature = 32.2673 degrees C. The pHzpcof the prepared photocomposites was found to be similar to 6.9.

Renewable energy integration and decarbonization of world energy systems are made possible by the use of energy storage technologies. As a result, it provides significant benefits with regard to ancillary power services, quality, stability, and supply reliability. The COVID-19 pandemic of the last few years has resulted in energy shortages in various industrial and technology sectors. As a result, diverse energy storage techniques have emerged as crucial solutions. Throughout this concise review, we examine energy storage technologies role in driving innovation in mechanical, electrical, chemical, and thermal systems with a focus on their methods, objectives, novelties, and major findings. As a result of a comprehensive analysis, this report identifies gaps and proposes strategies to address them. Researchers, industry experts, and policymakers will benefit from the findings of this review, which are expected to shape the trajectory of advances in renewable energy storage.

In this study, nanocomposites of different concentrations of zinc oxide nanoparticles impregnated with unsaturated polyester resin (UPR) were fabricated through the hand lay-up method. The amorphous behavior and granular morphology of synthesized ZnO/UPR nanocomposite were confirmed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Fourier transform infrared (FTIR) spectra illustrated a discrepancy in band intensities ascribed to the agglomeration of nanoparticles with the polymer. The UV–visible results demonstrated the redshift in the prepared nanocomposite initiated by the connections of nanoparticles with polymer chains, with a notable decrease in band gap energy from 3.37 to 3.15 eV as the filler concentration increased. As the content of zinc oxide increased, the agglomeration of nanoparticles in the matrix scattered the light, reducing the transmittance to nearly zero at wavelengths ranging from 200 to 370 nm for the 6

In the current work, a Pb-based metal-organic framework (Pb-MOF) is integrated with expanded polystyrene (EPS) waste for adsorptive desulfurization of dibenzothiophene (DBT) from gasoline. Pb-MOF is synthesized using lead nitrate and 1,4-benzenedicarboxylic acid and incorporated into a clear EPS-tetrahydrofuran solution through ultra-sonication to obtain the Pb-MOF-EPS membrane. The as-prepared Pb-MOF, pristine EPS, and PbMOF-EPS membranes are characterized by FTIR, SEM, and EDX. The Pb-MOF-EPS membrane is exposed to 10 ppm DBT solution made in n-hexane, at room temperature as it showed enhanced removal of DBT compared to pristine EPS. Moreover, the Pb-MOF-EPS membrane also demonstrated efficient removal of DBT from commercial gasoline without any sample pre-treatment requirement. The study exhibits that waste EPS can be functionalized with MOFs for adsorptive desulfurization thus, utilizing waste polymer for offering a sustainable and low-cost solution for thiophenes removal.

Environmental remediation has sought several innovative ways for the treatment of wastewater and captivated researchers around the globe towards it. Through this study, we aim to proceed with the efforts to foster sustainable and feasible ways for the treatment of wastewater. In this work, we report the sol-gel synthesis of CuO/MgO/ZnO nanocomposite and carry out their systematic characterization with the help of state-of-the-art analytical techniques, such as FTIR, SEM, TEM, PL, XRD, Raman, and AFM. The SEM along with TEM and AFM provided useful insights into the surface morphology of the synthesized nanocomposite on both 2D and 3D surfaces and concluded the well-dispersed behavior of the nanocomposite. The characteristic functional groups responsible for carrying out the reaction of Cu-O, Mg-O, and Zn-O were identified by FTIR spectroscopy. On the other hand, the crystalline behavior, crystal size, and dislocation strains of nanocomposite were calculated by XRD. For optical studies, photoluminescence spectroscopy was performed. Once the characterization of the nanocomposite was done, they were eventually treated against the toxic organic dye, methylene blue. The calculated rate constant values of k for CuO was 2.48× 10-3 min-1, for CuO/MgO (2.04× 10-3 min-1), for CuO/ZnO (1.82× 10-3 min-1) and CuO/MgO/ZnO was found to be 2.00× 10-3 min-1. It has become increasingly evident that nanotechnology can be used in various facets of modern life, and its implementation in wastewater treatment has recently received much attention.

Oxystelma esculentum plant is well-known for its broad spectrum of ayurvedic and conventional medicinal applications. The ethanolic crude extract of this plant was used to synthesize palladium nanoparticles in an environmentally friendly manner. The discreetness of the method adopted is the rapid sustainable fabrication of nanoparticles and the utilization of the nanoparticles for their effective catalytic activity. The systematic characterization of nanoparticles was done by standard analytical tools, UV eVis spectroscopy, dynamic light scattering, zeta potential, atomic force microscopy, X-ray diffraction, and scanning electron microscopy. The appearance of sharp peak at 471 nm indicated the adequate formation of palladium nanoparticles. The morphology and topography of nanoparticles were obtained by SEM and AFM. The crystalline nature of nanoparticles was analyzed by X-ray diffraction. The effective catalytic activity against the toxic organic dye methylene blue in the presence of the reducing agent NaBH4. Recognition of products formed by the degradation of methylene blue was then carried out through electrospray ionization coupled mass spectrometry. Moreover, the calculated Pd loading in the nanocomposites was 0.2 mmol/g. Meanwhile, to better evaluate the characteristic role of active species in catalytic degradation, the quenching study by scavengers methanol, ammonium oxalate, p-benzoquinone, and triethanolamine was also performed. Furthermore, the catalyst showed stability and reusability towards the degradation of a pollutant, thus can be also explored for other emerging pollutants. (c) 2023 Elsevier Ltd. All rights reserved.

Using plant extracts as eco-friendly reducing and stabilizing agents for the synthesis of nanoparticles has gained significant attention in recent years. The current study explores the green synthesis of silver nanoparticles (AgNPs) using the Avena fatua extract and evaluates their antifungal activity against Fusarium oxysporum f.sp. lycopersici (Fol), a fungal plant pathogen. A green and sustainable approach was adopted to synthesize silver nanoparticles before these nanoparticles were employed for anti-fungal activity. The primary indication that AgNPs had formed was performed using UV-vis spectroscopy, where a strong peak at 425 nm indicated the effective formation of these nanoparticles. The indication of important functional groups acting as reducing and stabilizing agents was conducted using the FTIR study. Additionally, morphological studies were executed via SEM and AFM, which assisted with more effectively analyzing AgNPs. Crystalline behavior and size were estimated using powder XRD, and it was found that AgNPs were highly crystalline, and their size ranged from 5 to 25 nm. Synthesized AgNPs exhibited significant antifungal activity against Fol at a concentration of 40 ppm. Furthermore, the inhibitory index confirmed a positive correlation between increasing AgNPs concentration and exposure duration. This study suggests that the combined phytochemical mycotoxic effect of the plant extract and the smaller size of synthesized AgNPs were responsible for the highest penetrating power to inhibit Fol growth. Moreover, this study highlights the potential of using plant extracts as reducing and capping agents for the green synthesis of AgNPs with antifungal properties. The study concludes that A. fatua extract can synthesize antifungal AgNPs as a sustainable approach with robust antifungal efficacy against Fol, underscoring their promising potential for integration into plant protection strategies.

Ammi visnaga is a biennial or annual herbaceous plant belonging to the family Apiaceae. For the first time, silver nanoparticles were synthesized using an extract of this plant. Biofilms are a rich source of many pathogenic organisms and, thus, can be the genesis of various disease outbreaks. In addition, the treatment of cancer is still a critical drawback for mankind. The primary purpose of this research work was to comparatively analyze antibiofilms against Staphylococcus aureus, photocatalytic activity against Eosin Y, and in vitro anticancer activity against the HeLa cell line of silver nanoparticles and Ammi visnaga plant extract. The systematic characterization of synthesized nanoparticles was carried out using UV–Visible spectroscopy (UV-Vis), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), dynamic light scattering (DLS), zeta potential, and X-ray diffraction microscopy (XRD). The initial characterization was performed with UV-Vis spectroscopy, where a peak appeared at 435 nm, which indicated the SPR band of the silver nanoparticles. AFM and SEM were performed to determine the morphology and shape of the nanoparticles, while EDX confirmed the presence of Ag in the spectra. The crystalline character of the silver nanoparticles was concluded with XRD. The synthesized nanoparticles were then subjected to biological activities. The antibacterial activity was evaluated by determining the inhibition of the initial biofilm formation with Staphylococcus aureus using a crystal violet assay. The response of the AgNPs against cellular growth and biofilm formation was found to be dose dependent. Green-synthesized nanoparticles showed 99% inhibition against biofilm and bacteria, performed excellent anticancer assay with an IC50 concentration of 17.1 ± 0.6 µg/mL and 100% inhibition, and photodegradation of the toxic organic dye Eosin Y up to 50%. Moreover, the effect of the pH and dosage of the photocatalyst was also measured to optimize the reaction conditions and maximum photocatalytic potential. Therefore, synthesized silver nanoparticles can be used in the treatment of wastewater contaminated with toxic dyes, pathogenic biofilms, and the treatment of cancer cell lines.

In this study, we report one-pot, single step synthesis of silver nanoparticles stabilized by using arbutin. The concentration of reducing agent (NaBH4) used in the preparation was kept at double, and arbutin was used as a stabilizing agent. The confirmation of prepared silver nanoparticles was done by color change and UV-Vis surface plasmon resonance peak at 435 nm in UV-Vis spectrum. Size dispersion of nanoparticles was carried out by Dynamic Light Scattering (DLS) and surface charge on nanoparticles. Stability was analyzed by Zeta potential. A strong negative charge indicated that nanoparticles are well stabilized throughout the solution. Morphology and 3D topographic images were obtained by Atomic Force Microscopy (AFM). The crystalline nature of nanoparticles was elucidated by X-ray diffraction analysis. The size and morphology of solid, well-grinded nanoparticles was proceeded by Scanning Electron Microscopy (SEM). The catalytic activities of nanoparticles were carried out against methylene blue, methyl orange, safranin, and eosin. The results demonstrated that synthesized silver nanoparticles commenced the degradation reaction of dyes mentioned. Prepared silver nanoparticles are found to have adequate catalytic activity, as it can be comprehended in time-dependent UV-Vis spectrums of dyes after treating them with AgNPs.

Low permeability is one of the barriers to the bioavailability of drugs through the oral route. The purpose of the present study was to design and optimize a sustained release and highly permeable hydrogel formulation of ganciclovir (GCV) by using response surface methodology (RSM). Carbopol 934P was used as a gelling agent, with two permeation enhancers, i.e., propylene glycol (PG) and oleic acid (OA), which were selected as variables X1 and X2, respectively. A total number of 13 runs prepared by using a central composite rotatable design (CCRD), followed by the preparation and evaluation of various parameters, including flux, lag time, Kp, and the rheological studies were evaluated. FTIR analysis showed that there was no interaction between the drug, polymer, and other excipients. The outcomes of ex vivo permeation studies have reviled that the values of flux, lag time, and kp were found to be 2.08800 ± 0.008, −6.982638 ± 0.01, −2.6917 ± 1.21, −29.7116 ± 0.68, and 0.00020, −0.00069, respectively. The spreadability index and the viscosity of the gel formulations were between the range of 2.63 ± 0.12–3.50 ± 0.08 and 5013.66 ± 1.69–5077.66 ± 2.05, respectively. On the other hand, the pH of all preparations was maintained at 7.02–7.13 pH to avoid skin irritation. After evaluating the said parameters, the composition for the optimized formulation is PG 5gm, OA 0.4gm, and carbopol 0.5gm. Furthermore, the findings have advocated that the hydrogels could be used, not only to deliver the drug in a sustained manner but also to improve the permeation of the drug and hence its bioavailability.

The work detailed in this thesis includes an extensive finite element simulation of low velocity impact behaviour of carbon fibre reinforced laminated composite panels subjected to flat and round nose impacts. Carbon fibre composites are being widely used in aerospace structures due to their high strength and stiffness ratios to weight and potential to be tailored for structural components. However, wing and fuselage skins are vulnerable to foreign object impacts during manufacturing and service from tools maintenance tools and tool box drops. Such impacts particularly from flat nose tool drops inflict internal damages that are difficult to detect through routine inspections. The internal damage (barely visible) may cause severe degradation of material properties and reduction in compressive strength that might lead in unexpected catastrophic failures. Such failures result in loss of human lives and structural assets. That is a major concern for the aircraft industry. Most of the existing research is based on damage detection and control to improve integrity of structures so that an aircraft could reach nearest safe place to avoid failure after damage is detected. It is very difficult to evaluate overall structural congruity and performance as structural degradation and damage progression occur after impacts. The impact is a dynamic event which causes concurrent loading and re-distributions of stresses once a ply fails or damage occurs. Most of the reported studies are based on physical experiments which are expensive, time consuming, and limited. The efficient way to predict performance evaluation of an impacted structural component is through integrated computer codes that couple composite mechanics with structural damage and failure progressions. Computational models can be very useful in simulating impact events, interpreting results, and making available the fast predictive tools for pre-design analysis and post-impact damage evaluations. This investigation is primarily simulation based that integrates experimentally and numerically evaluated impact response of laminates manufactured by AircelleTM Safran Ltd and HexcelTM Composites. Literature review and basic mathematical formulations relevant to the impact of composite laminates were commented. Pre-assumed damage induced static load-deflections simulation using “PTC Creo SimulateTM” were carried out for eight,sixteen, and twenty four ply laminates subjected point, low, medium, and large nose impacts. The methodology used was based on previous experimental studies that assumed that impact damage provides the same stress concentration effect as crack, regions of degraded materials, or softer inclusions. The same assumptions were incorporated into simulation by inserting pre-assumed damage zones equivalent to impactors’ nose tips with within the volume of the laminates. Damage initiation, growth, and accumulation were investigated in terms of real scenarios with reference to the undamaged specimens. Several internal damage mechanisms were analysed via damage shift in multiple locations throughout the laminates’ volumes. The simulations can be useful to predict and correlate information on: existence, type, location, and extent of the damage in the impacted system to applied load. With this information and the loads applied to the system, measures can be proposed to reduce adverse effects of the impact induced damage. The compressive residual strength after impact was predicted via buckling simulation models. The in-plane buckling analysis was implemented into PTC Creo SimulateTM. Effects of the pre-assumed damage ply, damage zone, and coupled damaged-ply with damage zone were investigated via through-thickness re-locations. Critical buckling load and mode shapes were predicted with reference to the mid-surface of the laminates. Local buckling was simulated by introducing damage in a single ply adjacent to surface of the sub-laminate. Cases of pre-assumed delaminated ply from top to the mid-surface were simulated. Cases of mix-mode buckling analysis were simulated from coincident and combined effects of pseudo damaged ply as well as damage zones. The simulations predicted information can be useful to predict useful life remains (prognosis) of the damaged system. The information could also be useful to predict residual strength of similar cases at the beginning from material level, loading scenarios, damage progression to component and system level at various rates. Material property characterization tests were conducted to verify the industry provided input and used in drop-weight impact simulations. The properties were augmented with micro-macro mechanics formulations to approximate full range of engineering constants from reliably determined Young’s modulus. The drop-weight simulation of eight, sixteen, and twenty four ply specimens of quasi-isotropic lay-ups having different thicknesses and impacted from round and flat nose impactors were implemented in the ABAQUSTM software using explicit dynamic method. Two independent models were implemented in the software. The first model simulates displacement, velocity, and acceleration quantities. The second model computes in-plane stresses required to efficiently evaluate 3D stresses. The in-plane stress quantities were numerically integrated through-the-thickness utilising equilibrium to evaluate ply-by-ply through-thickness stresses. The evaluated stress values were then utilised in the formulation set of advanced failure criteria to predict damage progression and failure modes. Simulation produced results were compared and verified against experiment produced data. Drop-weight impact tests were conducted to verify the selected simulation produced results. Non-destructive techniques and advanced data filtering algorithms available in MATLABTM were utilized to filter the noisy data and predict damage zone and load threshold. The selected simulation results were compared against the experimental data, intra simulation results, and the results available in the literature and have to agree up to 90%. The investigation concludes that the simulation models could efficiently predict low velocity impact response of variety of carbon fibre composite panels that could be useful for design development with reduced testing.

In this paper mathematical formulations and simulations were carried out for the prediction of through-thickness stress distributions of fibrous composite panels under variable shape impactors. Considerations were given to selective specimens from aerospace industrial environment to obtain the degree of uniformity of stress distributions throughout the out-of-plane geometry. The interlaminar stresses and strains induced in ‘thin’ laminates through application of membrane loads (i.e., in-plane loads) were also considered. Formulation was also developed for Poisson’s ratios. Finite Element Method (FEM) has received a tremendous attention in engineering and industry because of its diversity and flexibility as an analysis tool. The solutions to physical problems can be obtained very effectively and to a high degree of accuracy using FEM software packages. Therefore, the FEM was chosen to perform simulation in commercially available software ABAQUS. In-plane stresses were computed from the model and Trapezium rule was applied to calculate out-of-plane transverse shear stresses. The procedure is simple and efficient to predict 3-D transverse shear stresses from 2-D model. Results were compared with the results from the available literature and found to be in good agreement. Some of the results are shown herein in the form of tables and graphs.

The present investigation studies the use of powdered straw from Triticum aestivem for removal of lead (II) ions from its aqueous solution. Variation of contact time, biomass quantity, pH and temperature has been investigated as the major contributing factors. The sorption efficiency of the biomass has also been compared with that of cellulose, an adsorbent. At optimum conditions, the maximum removal of lead was observed to be 85% by dried biomass and 80% by cellulose for a 10 mg L-1 solution of lead (II) ions. The sorption process obeyed a heterogeneous adsorptin model (Freundlich Isotherm) rather than a monolayer one (Langmuir Isotherm). Release of H+ ions during process showed an ionexchange mechanism for metal removal by Tritcum aestivum.

Laboratory batch experiments with Azadirachata indicum indicated that this population had an excellent ability to bind lead (II) from its aqueous solution. The experiments carried out examined pH, biomass quantity, time of contact, and temperature dependency. Under optimum conditions, the removal of lead (II) was found to be around 95%. Column experiments were performed to examine the binding of lead (II) to silica-immobilized biomass under flow conditions. During this, a slight decrease in the pH of the effluents was also observed, implying an ion-exchange mechanism for metal binding.