Fixed-bed Adsorption Research Articles

Decolorization of tea industry wastewater utilizing tea waste bio-adsorbent in fixed-bed adsorption column: breakthrough curves analysis and modeling

Decolorization of tea industry wastewater utilizing tea waste bio-adsorbent in fixed-bed adsorption column: breakthrough curves analysis and modeling

Dynamic of CO2 adsorption in a fixed bed of microporous and mesoporous activated carbon impregnated with sodium hydroxide and the application of response surface methodology (RSM) for determining optimal adsorption conditions.

Microporous and mesoporous activated carbon produced from longan-seed biomass were impregnated with NaOH and used to capture CO2 from a simulated flue gas in a fixed-bed column. The process variables that were studied included types of activated carbon as characterized by the volume ratio of micropores and mesopores (Vmic/Vmes), adsorption temperature, NaOH loading, gas feed rate and the adsorbent amount. All five process variables affected the two important breakthrough parameters, namely the breakthrough time (tB) and CO2 adsorption capacity at breakthrough time (qB), with different trends and degrees. However, it was only the NaOH loading that showed a characteristic of an optimum loading that provided the maximum of the breakthrough parameters. It was found that an approximate 45% increase in the adsorbed amount of CO2 could be achieved with the activated carbon impregnated with around 1 weight % NaOH solution as compared to the case of the non-impregnated carbon. The response surface methodology (RSM) was applied to develop the correlations for both tB and qB and the maximum predicted qB of 33.58mg/g was derived at the NaOH loading of 76.5mg/g carbon, Vmic/Vmes of 2.83, adsorption temperature of 20°C, gas feed rate of 156kg/m2-h and adsorbent amount of 51kg/m2 of column cross-section area. The Klinkenberg's breakthrough model was able to describe the CO2 breakthrough curves reasonably well for all the tested conditions. The analysis of the two model parameters, the affinity constant (K) and the effective pore diffusivity (De), revealed that the optimum Vmic/Vmes that provided the maximum K value was around 2.90, corresponding to the activated carbon that contains 74% and 26% by volume of micropores and mesopores, respectively. The proper volume ratio of micropores and mesopores along with alkali addition into activated carbon can be effectively used for maximizing CO2 adsorption in a fixed-bed adsorption system.

Nitrate removal from aqueous solution by glucose-based carbonaceous adsorbent: Batch and fixed-bed column adsorption studies

In the present study, the glucose-based carbonaceous adsorbent was prepared from glucose, melamine and urea by using ZnCl2 activation and heated at 550°C under N2 flow. The sample was treated for the 1st, 2nd and 3rd activation process, and they were characterized by N2 adsorption and desorption isotherms, elemental analysis and X-ray photoelectron spectroscopy (XPS). The results showed that the content of nitrogen increased and that of oxygen decreased with the increasing of the number of activation process. The adsorbent obtained after the 2nd activation showed the best adsorption properties and was used in batch and fixed-bed column adsorption studies. In batch adsorption experiments, we investigated the factors affecting nitrate adsorption such as initial concentration, solution pH, adsorption isotherms and adsorption kinetics. The isotherm data and kinetic data were fitted well to the Langmuir isotherm model and pseudo-second-order model, respectively, and the maximum adsorption capacity calculated by Langmuir model was 1.58 mmol/g at pH 3. The adsorption performance of the adsorbent in industrial application mode was also investigated by fixed-bed column experiments. The breakthrough time of the packed column was 160 min for the initial nitrate concentration of 200 mg/L at pH 3. The saturated column could be regenerated by 1 mol/L HCl and reused for at least 5 adsorption-desorption cycles. The column showed good adsorption performance in both coexisting ions solution and real contamination water.

Leveraging Diffusion Kinetics to Reverse Propane/Propylene Adsorption in Zeolitic Imidazolate Framework-8.

The separation challenge posed by propylene/propane mixtures arises from their nearly identical molecular sizes and physicochemical properties. Metal-organic frameworks (MOFs) have demonstrated potential in addressing this challenge through the precision tailoring of pore sizes and surface chemistry. However, introducing modifications at the molecular level remains a considerable hurdle. This work presents an approach to reversibly tune the propylene/propane adsorption preference in zeolitic imidazolate framework-8 (ZIF-8) by manipulating the particle size and gas flow rate. Systematically increasing the ZIF-8 crystals from 9 to 224 μm restricts propane diffusion, thereby reversing its preferential adsorption over propylene. Furthermore, raising the gas flow rate of mixed propylene/propane shifts the rate-determining breakthrough step from thermodynamic equilibrium to kinetics, again reversing the adsorption preference in a particular ZIF-8 sample. We propose "dynamic selectivity (Sd(t))" as a concept that incorporates both thermodynamic and kinetic factors to elucidate these unexpected findings. Moreover, the driving force equation, grounded on the concept of Sd(t), has improved the precision and stability of the computational simulation for fixed-bed adsorption processes. This work underscores the potential of diffusion-based modulation, implemented through manageable external changes, as a viable strategy to optimize separation performance in porous adsorbent materials.

Effect of Bed height on Chromium (III) and Manganese (IV) Fixed-bed Column Adsorption from Crude Oil Contaminated Water from Okuru River in Ogali, Eleme, Rivers State, Nigeria

Effect of Bed height on Chromium (III) and Manganese (IV) Fixed-bed Column Adsorption from Crude Oil Contaminated Water from Okuru River in Ogali, Eleme, Rivers State, Nigeria

Fixed-Bed Column Adsorption Studies of Synthetic Organic Chemicals Using Carbonized and Surface-Modified Carbons from Nipa Palm Leaves

Fixed-Bed Column Adsorption Studies of Synthetic Organic Chemicals Using Carbonized and Surface-Modified Carbons from Nipa Palm Leaves

Effect of montmorillonite nanosheets on the adsorption performance of hydrogel beads and the study of column adsorption

In this work, hydrogel beads with 3D network structure were successfully prepared using montmorillonite nanosheets (MMTNS) combined with macromolecule polymers. Batch adsorption tests revealed that the increase in exfoliation degree of MMTNS was beneficial to improve the methylene blue (MB) adsorption on hydrogel beads (HB). In addition, the HB with 25 % MMTNS-3 dosage achieved high mechanical strength and reached the maximum adsorption capacity of 543.1 mg/g. Effects of MB concentration (40–120 mg/L), adsorbent dosage (1–1.5 g) and flow rate (5–15 mL/min) on fixed-bed column adsorption indicated that the HB column exhibited an excellent dynamic adsorption performance and recycling performance, much better than the D113 resin. The good fits of Pseudo-first-order model and Pseudo-second-order model and a better Langmuir model fitting result implied a monolayer chemical adsorption and physical adsorption nature of MB on HB. Moreover, scanning electron microscope combined with the energy dispersive spectrometer, fourier transform infrared spectroscope and X-ray photoelectron spectroscopy measurements indicated that the adsorption mechanism was mainly attributed to Ca ion-exchange and chemical bonding of –COOH and –OH groups with MB. Such hydrogel beads showed a good potential in the application of practical wastewater treatment.

Multidimensional decipherment of interactions in invert sugar–amino acid co-degradation colorants (IACDCs) capture by polyamine co-modified shaddock peel cellulose/graphene oxide aerogel

The development of an environmentally friendly scavenger with an outstanding ability to eliminate IACDCs from molasses-based distillery wastewater is essential for the safety of aquatic ecosystems and organisms. By combining polyamine co-modified shaddock peel cellulose (SPC) and graphene oxide (GO), a multistage porous aerogel (i.e., CP-GO/SPA) was constructed for the highly effective capture of IACDCs. CP-GO/SPA exhibited a surprisingly high IACDC adsorption capacity (1157 mg/g, which was 1.5–100 times that of previously reported ones). It also had an ultrafast adsorption mass transfer (AMT) rate. Advanced AMT-resistance models reveal that the capture on active site is the main AMT resistance, whereas liquid-film and pore diffusion are quite fast. CP-GO/SPA exhibited excellent reusability (>90% IACDC removal efficiency after six cycles) and considerable potential for industrial applications (i.e., treatment of actual wastewater by fixed-bed adsorption). The polyamine co-modified SPC and GO endowed CP-GO/SPA with substantial amine groups and high affinity for water, as validated by advanced molecular dynamics simulations. These features are extremely conducive for capturing electronegative and water-soluble IACDCs. A series of characterizations and multiple quantum chemical theory calculations (including ETP, ALIE, FMOs, IGM, and HIS analyses) further revealed the adsorption mechanisms from a molecular perspective. The IACDC capture by CP-GO/SPA resulted from charge, electron sharing, and van der Waals interactions. However, charge interactions played a dominant role. The optimal capture configurations were visualized at the molecular level, and the H-bond donor–acceptor relationship was determined. The IACDCs act as H-bond acceptors in a diverse range of capture configurations.

Coupled adsorption-phytoremediation treatment of cellulose-reactive blue dye in a sustainable multi-step pilot-scale process.

A single-step dye removal strategy from wastewater is inadequate for concentrations above 100mg/L. In order to address this limitation, the adsorption of high dye concentrations followed by phytoremediation is a potential approach for the treatment of dye-contaminated wastewater. This combined method utilizes physical adsorption and biological processes to remove dyes from wastewater. Herein, we investigated a pilot-scale multi-step cascaded process where batch adsorption and fixed-bed column adsorption were combined with phytoremediation to remove cellulose-reactive blue dye at 200 to 500mg/L concentrations. The batch adsorption utilized low-cost water hyacinth root powder (WHRP) bioadsorbent having 670 m2/g surface area, whereas the fixed-bed column adsorption used sand having a surface area of 75 m2/g. The phytoremediation process utilized water hyacinth plants in a series of ponds. The effluent from one unit is fed to the next until the dye is removed to more than 98% for all concentrations considered in this study. Pilot-scale experimental data fitting to adsorption isotherms and kinetics were performed to gain insight into the pilot-scale adsorption mechanism. The fixed-bed sand column adsorption was conducted at different inlet dye concentrations, flow rates, and bed heights. The breakthrough curves were fit to the Thomas, Yoon-Nelson, and Bohart-Adams models. The effluent from the fixed-bed column was transferred to phytoremediation ponds, where complete dye removal was achieved. Overall, data collectively presented in this study demonstrated that the combined adsorption and phytoremediation approach offers a potential solution for the remediation of high dye concentration in wastewater, providing an effective and sustainable treatment option.

Efficient defluoridation of water by employing hybrid nanosized cerium oxides embedded within cross-linked cellulose foam

Efficient defluoridation utilizing current hybrid nano-oxides remains a great challenge because of low loading capacity and hindered nucleation during immobilization. In this study, a new adsorbent for defluoridation was developed by encapsulating nanosized cerium oxides within a cross-linked network of cellulose foam using an embedding method. The controllable structure, uniform dispersion, and high content of NCO endowed the composite with high efficiency for fluoride removal. The batch adsorption experiments exhibited a broad pH range (2.0–6.0) for optimal fluoride adsorption and confirmed that NCO@CF had a maximum adsorption capacity of 109.88 mg·g−1 at pH 4.0, which was much higher than that of other materials. Exceptional adsorption selectivity was also observed, indicating strong attraction between NCO@CF and fluoride ions, even at high concentrations of competing ions. X-ray photoelectron spectrogram and the Fourier transform infrared spectra analyses suggested that the defluoridation mechanism involved ligand exchange and inner-sphere complexation between NCO@CF and fluoride. Batch adsorption–regeneration cycles demonstrated that NCO@CF could be effectively and consistently regenerated using an alkaline solution. In fixed-bed adsorption experiments, remarkable working capacities of 1782 and 480 bed volume were observed for NCO@CF at pH 4.0 and 6.0, respectively. The findings of this study provide insights into the practical application of hybrid NCO in efficient defluoridation from water.

Efficiency, mechanism and application prospect of ammonium adsorption and desorption over a sodium-acetate-modified synthetic zeolite.

Adsorption is an effective approach for remediating ammonium pollution, and zeolite has exceptional efficacy for the adsorption of ammonium. The investigation of ammonium adsorption using coal-fly-ash-based zeolite has gained remarkable attention in contemporary research. In this work, a sodium-acetate-modified synthetic zeolite (MSZ) was used to absorb ammonium in simulated wastewater. The MSZ had an adsorption capacity for ammonium of 27.46 mg g-1, and the adsorption process followed the Langmuir isotherm model and pseudo-second-order kinetics model. The adsorption and desorption of ammonium were controlled by ion exchange, pore diffusion, and electrostatic attraction processes. Ion exchange was responsible for 77.90% of the adsorption process and 80.16% of the desorption process. The MSZ was capable of continuously removing large amounts of ammonium from wastewater through fixed bed adsorption. After 5 regeneration cycles, MSZ still maintained 75% adsorption characteristics for ammonium. Using MSZ adsorbed with ammonium as a soil amendment increased the germination rate of mung beans by 10%. Furthermore, it also increased the stem length, root length, and fresh weight by 20-30%. These findings suggest that MSZ provides a promising application prospect to mitigate ammonium pollution and recycle ammonium resources.

Two Dimensional (2D) Multi-Scale Modeling of Fixed Bed Adsorption Column Using Computational Fluid Dynamics (CFD) Simulation

Natural gas has received much attention with low environmental impact in recent decades as a fuel source. Flexible natural gas purification systems with minimal carbon dioxide footprints are growing in need. There are few techniques that base current industrial decontamination systems on among which adsorption is considered to be the promising one. Herein multi-scale models have advanced to simulate the hydrodynamics and adsorption-dynamics of gases in the adsorption column, a mixture of (CO2 and CH4) In the current analysis, a two-dimensional (2D) porous media was modelled using CFD multi-scale model. A fixed-bed adsorption column was used for the removal of carbon dioxide (CO2) from methane (CH4) and the silicate adsorbent adsorption kinetics linear driving force (LDF) model was simulated to describe it. The adsorption phenomena simulation inside the fixed bed using CFD method was implemented and using user defined function (UDF) and the user defined scalar (UDS), porous media concept and the mass transfer coefficient for gas components (CO2/CH4) were developed. The experimental data was used to validate the model which was collected based on varying a number of laboratory conditions. The simulation results prediction of methane recovery and breakthrough curves shows an acceptable agreement with the experimental data with the highest error lower than 3.5%. Moreover, the effect of feed concentration (15,35 and 75%), feed velocity effect (0.03,0.05 and 0.07 m/s), effect of bed porosity (0.42, 0.52 and 0.62), effect of inlet concentration on temperature (15, 30 and 60%), particle radius (0.0006, 0.0007 and 0.0008m) and effect of bed height (0.3, 0.4 and 0.5m) were investigated. The present results received from the CFD approach suggests that they are capable to predict the adsorption phenomena and hydrodynamics in the adsorption column.

Development of new effective activated carbon supported alkaline adsorbent used for removal phenolic compounds

Phenolic (phenol) compounds are the major contaminates in wastewater, which can have a considerable negative influence on the environment and health of human. Adsorption is an efficient process that is widely applied in order to eliminate phenol in wastewater. In recent, Adsorption process has acquired a lot of attentiveness owing to its relative moderate operating conditions. However, adsorption process needs considerable ameliorations in terms of adsorbent modification, process type, productivity, and conversion rate. This work studies the development of a fast and effective adsorption process in a fixed bed adsorption column (FBAC) in order to reach safe and continuous elimination of phenolic compounds. Several adsorption parameters (reaction temperature, adsorbent bed height, feed flow rate and kind of adsorbent) were studied to achieve the highest removal of phenolic compounds. The adsorption process was conducted in the presence of two type of adsorbents (activated carbon (AC), and KOH/AC), 73% and 94% of phenol elimination were attained, respectively, at 10 cm bed height, 1 ml/s feed flow rate, and 75 °C reaction temperature. The adsorbents activity was investigated after six consecutive adsorption cycles at the best process conditions, and the adsorbents show high stability in terms of phenolic compounds adsorption. After that, the spent adsorbents were regenerated by utilizing various solvents (methanol, ethanol and iso-octane), and the results show that iso- octane achieved highest regeneration efficiency. The adsorption process was implemented in the adsorption column that the performance is possibly to be adjusted at an industrial scale since it can be scaled up predictably.

Hydrogen Sulfide Adsorption from Natural Gas Using Silver-Modified 13X Molecular Sieve.

The removal of hydrogen sulfide from natural gas and other gases such as biogas, refinery gases, and coal gas is required because it is toxic and corrosive, even in traces. Zeolites are widely used in the removal of H2S from the abovementioned gases. In this work, we prepared an Ag-exchanged 13X molecular sieve by using different concentrations of AgNO3 to increase its adsorption properties. XRD, SEM, and BET techniques were used to characterize samples. To determine the adsorption properties of each of the samples, a laboratory setup with a fixed-bed adsorber was utilized. The adsorption capacity of modified 13X increased when the molar concentration of AgNO3 increased from 0.02 M to 0.05 M. However, the breakthrough time was attained quicker at a high molar concentration of 0.1 M AgNO3, indicating a low adsorption capacity. When compared to unmodified 13X, the adsorption capacity of AgII-13X increased by about 50 times. The results of this study suggest that the silver-modified 13X molecular sieve is highly effective at extracting H2S from natural gas.

Gum Arabic tree biomass derived activated carbon for fluoride sequestration in batch and fixed bed processes: kinetics, thermodynamics and column adsorption modeling

The biomass obtained from the stem of Gum Arabic tree was used to prepare a thermally activated carbon through pyrolysis at 800 °C. The activated carbon tagged GAAC-800 was used as adsorbent for the fluoride sequestration in a batch and a fixed-bed reactor in a continuous column systems. The surface morphology, elemental composition as well as particle size distribution of the adsorbent was investigated with Scanning Electron Microscopy (SEM), Elemental and Particle Size Analyzers. Also, the influence of initial fluoride concentrations, column packing height and the flow rate on the column efficiency were examine while the efficiency of batch process as a function of contact time and temperature was also investigated. It was found that the kinetic of the process was best fitted with second order model, while the mechanism was best explained by interparticle diffusion model. In addition, the Langmuir Isotherm model showed that the maximum monolayer adsorption capacity of fluoride removal was 71.93 mg/g. The breakthrough curve from the fixed bed adsorption data were well modeled by Adams-Bohart, Yoon-Nelson and Clark model. The models were judged using Akaike Information Criteria (AIC) values after statistical evaluation. GAAC-800 removed fluoride from aqueous solution comparably higher than other adsorbent in its category in batch and continuous column systems.

High removal performance of reactive blue 5G dye from industrial dyeing wastewater using biochar in a fixed-bed adsorption system: Approaches and insights based on modeling, isotherms, and thermodynamics study

In an eco-friendly context, an adsorption study was performed in a fixed-bed column system to remove organic pollutants from dyeing wastewater, testing preliminary theoretical models and reactive blue 5G (RB5G) dye as a reference pollutant and tilapia bone-based biochar as an alternative adsorbent. Adsorption approaches in removing RB5G dye molecules from synthetic solutions were performed to understand better based on a reliable mathematical representation and provide insights and strategies into treating dyeing wastewater. Initial dye concentration, pH, temperature, and stirring velocity were used as process variables to search for maximal capacity in batch mode. Thermodynamic analysis and a series of phenomenological kinetic models were applied to understand and interpret the mechanisms and develop a predictive model for a fixed-bed column adsorption system, trying to minimize the total organic carbon (TOC) in dyeing wastewater. An intraparticle mass transfer resistance model and the Langmuir-BET isotherm better represented kinetic and equilibrium data, respectively. In the Langmuir-BET model context, the first monolayer has systematically changed its predicted Langmuir adsorption capacity from 18 mg g−1 to 31 mg g−1 being favored by the increase in temperature of 30 to 60 °C, respectively, with the lowest Gibbs free energies for the multilayer formation ruled by weak physical interaction. Theoretical values of the breakpoint, full saturation time, and useful column height were well predicted related to their experimental ones, including the better fitting of all adsorption curve patterns in a fixed-bed adsorption column system with an adsorption capacity of 30.4 mg g−1 (at 50 °C) for an inlet of 200 mg L−1 RB5G solution resembling almost the same value found in batch mode (30.9 mg g−1). After treating the dyeing wastewater characterized by 75 mg L−1 RB5G dye, the adsorption capacity of 23.3 mg g−1 was attained with a 12% loss in comparison with the expected one for a synthetic RB5G solution due to adsorptive competition with other organic pollutants. Finally, a final TOC value near 5.0 mg L−1, the maximum allowed for the Brazilian environmental council, was attained with an almost zero RB5G concentration after a 5-h breakpoint.

A convenient functionalization strategy of polyimide covalent organic frameworks for uranium-containing wastewater treatment and uranium recovery

The purpose of this research was to design and synthesize an adsorbent based on polyimide covalent organic frameworks (PICOFs) for uranium-containing wastewater treatment and uranium recovery. A modified solvothermal method was innovatively proposed to synthesize PICOFs with high specific surface area (1998.5 m2 g−1) and regular pore structure. Additionally, a convenient functionalization strategy of PICOFs was designed through polydopamine (PDA) and a well-dispersed polymer (MPC-co-AO) containing multiple functional groups, forming stable composite (PMCA-TPPICOFs) in which the hydrogen bonding and cation-π interactions between PDA and MPC-co-AO played a key role. The obtained PMCA-TPPICOFs as an adsorbent exhibited strong selectivity for uranyl ions (maximum adsorption capacity was 538 mg g−1). In simulated wastewater with low uranium concentrations, the removal rate reached 98.3%, and the concentration of treated simulated wastewater met discharge standards. Moreover, PMCA-TPPICOFs was suitable for fixed-bed column adsorption because of its favorable structure. According to the research about adsorption mechanism, the adsorption primarily relied on electrostatic interaction and complexation. In summary, PMCA-TPPICOFs exhibited good potential for uranium-containing wastewater treatment, expanding the application of PICOFs. And the proposed functionalization strategy and modified solvothermal method may promote research in the fields of material functionalization and COFs synthesis. Environmental ImplicationUranium is a raw material for nuclear energy applications, which is toxic and radioactive. If uranium is discharged with wastewater, it would not only pose a threat to the environmental protection and life safety, but also cause the loss of precious nuclear raw materials. Although adsorption was considered to be an effective way to remove uranium, many of the developed adsorbents were difficult to apply due to the harsh wastewater environment and complex preparation processes. This study reported a novel adsorbent and a new functionalization strategy, which was expected to solve the problem of uranium recovery in wastewater.

Fixed-Bed Adsorption of an Azo Dye (Methyl Orange) onto Chemically and Thermally Regenerated Activated Carbons

In this study, the effectiveness of the recovery method for spent granular activated carbon (SGAC) for application in dye removal was evaluated. A comparative study of the textural (porosity), compositional, surface functionality, and adsorption performance of chemically (CAR400) and thermally regenerated activated carbons (CAR700 and CAR900) was conducted for the elimination of methyl orange (MO) dye by using a fixed-bed system. The results were compared with those of commercial activated carbon (CA). The influence of parameters such as the initial dye concentration, the flow rate, the internal diameter of the column, and the bed height was evaluated. Adsorption data were modelled by using the Thomas, Adams–Bohart, and Yoon–Nelson equations. The CAR400 activated carbon had a microporosity (1045 mg/g) comparable to that of the reference commercial (CA) activated carbon (1052 mg/g) but exhibited the least adsorption capacity. The breakthrough curves were best described by the Thomas model more than the Bohart–Adams and Yoon–Nelson’s models. Thomas’s model depicted that an increase in column diameter resulted in a decrease in the maximum adsorption capacity (qo). The CAR900 material exhibited the highest adsorption capacity (15.72 mg/g) comparable to that of commercial activated carbon, CA (16.90 mg/g). These results show that the physical/thermal regeneration of spent granular activated carbons (SGAC) is more suitable for the valorization of these waste materials for water purification applications.

Synthesis of iron oxide nanoparticles encapsulated poly(styrene‐co‐4‐vinyl pyridine) nanocomposites for column adsorption and photocatalytic degradation of para nitrophenol from water

AbstractStyrene (St), 1,4 vinyl pyridine (4VP) monomers and divinyl benzene (DVB) monomer‐cum‐crosslinker at different molar ratios were subjected to emulsion polymerization in the presence of FeCl2, 6H2O/FeCl3⋅4H2O followed by the treatment with an aqueous ammonia solution to produce several iron oxide nanoparticles (IONs) impregnated crosslinked copolymer composites. The resulting polymer metal nanocomposites (PMNCs) were characterized by FTIR, proton and 13C NMR, UV–visible spectroscopy, XRD, XPS, DLS, magnetic properties, SEM and TEM. The PMNCs were used for batch and column adsorption and photocatalytic degradation of p‐nitrophenol (PNP) from water. The PMNC4 composite prepared with an styrene:4VP molar ratio of 5:1 (16.7 mol% 4VP), 4 wt.% DVB crosslinker and 0.025/0.05 molar ratios of Fe(II)/Fe(III) salts leads to an optimum batch equilibrium adsorption (qe, mg/g)/removal% of 496.36/99.3 PNP from aqueous PNP of concentration 100 mg/L. The same composite showed an equilibrium PNP adsorption (qe) of 114.2 mg/g polymer and a removal% of 26.8 for an inlet feed concentration (Ci, mg/L)/flow rate (Qt, mL/min)/bed height (h, mm) of 100/30/30 in a fixed bed. The PMNC4 polymer showed a photodegradation efficiency of 98% with a 1st order rate constant of 0.029 min−1 after 70 min of degradation of 100 mg/L PNP in solar light.Highlights Copolymer network of styrene, 4 vinyl pyridine and DVB were synthesized. Iron oxide nanoparticles were introduced into the network in‐situ during synthesis. The metal polymer nanocomposites (PMNCs) were characterized. Synthesis parameters were optimized with respect to batch adsorption of PNP. PMNCs showed excellent fixed bed adsorption and photocatalytic degradation of PNP.

Utilisation of Clamshell Waste for Removing Mercury From Water: Fixed Bed Adsorption and Modelling Studies

The present communication investigated the sustainable utilization of the clamshell waste powder (CSP) for eliminating mercury through fixed bed adsorption. This CSP is freshly prepared and packed in a stable multi-port column. Their breakthrough performance in the column is evaluated by varying its bed depth (5, 10, 15, 20 and 25 min) and flow rate (8, 10 and 12 mL/min). The CSP column’s design parameters and kinetic behavior are estimated from its breakthrough curve and validated using column models. The results revealed that slow saturation of the CSP bed and maximum adsorption capacity (2.8 mg/g) occurred at lower column depth (5 cm) and elevated influent flow rates (12 mL/min). Moreover, the mass transfer zone exhibited fluctuations with elevated column depth, indicating the presence of non-ideal conditions. The YN model showed superior fitness for mercury removal using CSP. The dynamic studies showed that CSP is a cost-effective, eco-friendly, biocompatible and sustainable adsorbent that can be successfully employed for treating industrial effluent.