Column Studies Research Articles

Treatment Efficiency and Recovery in Sand Filters for On-Site Wastewater Treatment: Column Studies and Reactive Modeling

Treatment Efficiency and Recovery in Sand Filters for On-Site Wastewater Treatment: Column Studies and Reactive Modeling

Assessment of Recycled and Manufactured Adsorptive Materials for Phosphate Removal from Municipal Wastewater

AbstractElevated concentrations of phosphorus (P) and other nutrients common in wastewater treatment plant (WWTP) effluent have been shown to contribute to the proliferation of harmful algal blooms, which may lead to fish kills related to aquatic hypoxia. Increased understanding of the negative effects associated with elevated P concentrations have prompted more strict regulation of WWTP effluent in recent years. The use of low‐cost and potentially regenerative adsorptive phosphate filters has the potential to decrease P concentrations in WWTP effluent released to natural waters. This research focuses on assessing the capacities of recycled concrete aggregate (RCA), expanded slate, and expanded clay to remove phosphate from P‐amended WWTP effluent. Results from a flow‐through column study indicate that RCA consistently removed an average of 97% of phosphate over 20 weeks of continuous flow at an 8‐hour hydraulic retention time (HRT). Expanded clay removed an average of 63% of introduced phosphate but decreased in removal capacity from 91 to 42% over the 20‐week duration. Sorption data from batch studies were fitted to Langmuir models and RCA was shown to have the highest maximum sorption capacity (6.16 mg P/g), followed by expanded clay (3.65 mg P/g). RCA and expanded clay are promising options for use in passive filters for further reduction of phosphate from WWTP effluent.

Successful removal of fluoride from aqueous environment using Al(OH)3@AC: column studies and breakthrough curve modeling.

In this study, we discuss the removal of fluoride from water through column adsorption methods using Al(OH)3@AC as a functional granular activated carbon. The height of the bed, fluoride concentration, and flow rate are the experimental factors used to obtain the breakthrough curves. As the flow rate increased, the breakthrough and saturation times decreased. The analysis of simplified column models, such as the Adams-Bohart, Thomas, and Yoon-Nelson models, revealed that the Clark model best described the adsorption process when fitting the experimental data. The obtained breakthrough curves agreed with the corresponding experimental data. The highest capacity for adsorption obtained during the column procedure was found to be 41.84 mg g-1 with a bed height of 3 cm, an initial fluoride concentration of 10 mg L-1 and a flow rate of 7.5 mL min-1.

Gas hold-up, pressure drop and flow regime study in semi-batch PSRBC bubble column

Gas hold-up, pressure drop and flow regime study in semi-batch PSRBC bubble column

Non-derivatizing solvent assisted waste-derived cellulose/ MOF composite porous matrix for efficient metal ion removal: comprehensive analysis of batch and continuous packed-bed column sorption studies.

The use of metal-organic frameworks (MOFs) for wastewater treatment in continuous operation is a major challenge. To address this, the present study demonstrates the eco-friendly and economic synthesis of Ca-MOF immobilized cellulose beads (Ca-MOF-CB) derived from paper waste. The synthesized Ca-MOF-CB were characterized using standard analytical techniques. Batch sorption studies were performed to check the effect of cellulose composition (wt%), Ca-MOF loading, contact time, and initial metal ion (Pb2+, Cd2+, and Cu2+) concentration. Ca-MOF-CB beads exhibited outstanding equilibrium sorption capacities for Pb2+, Cd2+, and Cu2+, with estimated values of 281.22 ± 7.8, 104.01 ± 10.58, and 114.21 ± 9.68 mg g-1, respectively. Different non-linear isotherms and kinetic models were applied which confirmed the spontaneous, endothermic reactions for the physisorption of Pb2+, Cd2+, and Cu2+. Based on the highest equilibrium sorption capacity for Pb2+ ion, in-depth parametric column studies were conducted in an indigenously developed packed-bed column set-up. The effect of packed-bed height (10 and 20 cm), inlet flow rate (5 and 10 mL min-1), and inlet Pb2+ ion concentration (200, 300, and 500 mg L-1) were studied. The breakthrough curves obtained at different operating conditions were fitted with the empirical models viz. the bed depth service time (BDST), Yoon-Nelson, Thomas, and Yan to estimate the column design parameters. In order to determine the financial implications at large-scale industrial operations, an affordable synthesis cost of 1 kg of Ca-MOF-CB was estimated. Conclusively, the present study showed the feasibility of the developed Ca-MOF-CB for the continuous removal of metal ions at an industrial scale.

Silver nanoparticles (Ag-NPs) embedded in zeolite framework: A comprehensive study on bromide removal from water, including characterization, antibacterial properties, and adsorption mechanisms

In this comprehensive study, a novel adsorbent material comprising silver nanoparticles (Ag-NPs) zeolite composite was synthesized and characterized for its efficacy in removing bromide ions from water. Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray Diffraction (XRD) analyses confirmed the successful integration of Ag-NPs within the zeolite framework, ensuring structural integrity and chemical composition. Under varying operational conditions, the batch experiments consistently exhibited the zeolite with Ag-NPs as superior in bromide removal efficacy compared to zeolite alone, both achieving over 96% removal efficiency. Moreover, the adsorption kinetics aligned well with a second-order reaction model. Furthermore, column studies revealed that zeolite with Ag-NPs performed better than zeolite in maintaining efficient bromide removal over extended durations, highlighting its long-term operational potential. Thermodynamic investigations indicated the exothermic and spontaneous nature of the bromide ion adsorption process, supported by negative ΔG° values. Across temperatures ranging from 22 to 52 °C, the ΔG° values were observed to range from − 1.275 to − 0.049 kJ/mol for bromide removal using zeolite and − 1.90 to − 0.909 kJ/mol for zeolite+Ag-NPs, indicating their favorable adsorption characteristics. Furthermore, the study revealed the remarkable antimicrobial properties of the zeolite with Ag-NPs, as evidenced by a significant reduction in bacterial growth compared to pure zeolite, suggesting its dual application potential for both bromide removal and water disinfection. In conclusion, the integration of Ag-NPs into zeolite represents a promising potential for sustainable and multifunctional water treatment solutions.

Enhancing manganese sorption: Batch and fixed-bed column studies on activated zeolite

Dissolved Mn2+ in groundwater is dangerous for human health since it may act as a neurotoxin. To address this issue, sorption has emerged as an environmentally-friendly technology for Mn2+ removal. This study aimed to assess the effect of activation of Chilean natural zeolite, by modification of its compensating cations with NaCl, on its capacity for Mn2+ removal using batch and fixed-bed column studies. The natural and activated zeolites were characterized by SEM-EDS, TXRF, XRD, and N2 adsorption assays. The results of batch studies demonstrate that Na+ enhances the Mn2+ removal capacity of these zeolites from 4.55 to 5.9−1, with negligible changes in the pore structure. The experimental data fitted well with the pseudo-second-order kinetic and Langmuir adsorption models. Furthermore, MnOx(s) formed during the Mn2+ removal was identified on the surface of the zeolite by XRD and SEM-EDS analysis. The fixed-bed column studies were conducted at two bed heights: H1 (5 cm) and H2 (10 cm). The breakthrough curves adjusted to models of Thomas and Dose-response. The dose-response model adequately described both experimental data with an R2 > 0.90. The Mn2+ adsorption capacity of the system (qmdr) was 2.38 and 5.13 mg g−1, for H1 and H2, respectively. The regeneration of the activated zeolite was achieved using NaCl solution improving the efficiency of Mn2+ removal after reuse. This work highlights natural zeolite potential as an effective material for Mn2+ removal and as a viable technology to improve the water quality affected by geogenic contamination.

Adsorption of common greywater pollutants and nutrients by various biochars as potential amendments for nature-based systems: Laboratory tests and molecular dynamics

Spruce wood and Typha (wetland plant) derived biochars pyrolyzed at 350 °C and 600 °C were tested for their sorption affinity for organic pollutants (diclofenac, methylparaben, benzotriazole and sodium 1-decanesulfonate) and nutrients (nitrate, ammonium, phosphate and boron) commonly found in greywater. Batch and column studies combined with molecular dynamics modelling determined the sorption capacity, kinetics, and described the underlying mechanisms. The spruce biochar (600 °C) exhibited the highest sorption capacity mainly for the tested organics. The dynamic test performed for spruce biochar (600 °C) showed that the magnitude of desorption was low, and the desorbed amount ranged between 3 and 11 %. Molecular dynamics modelling (a computational tool for elucidating molecular-level interactions) indicated that the increased sorption of nitrate and boron on spruce biochar (600 °C) could be attributed to hydrophobic interactions. The molecular dynamics shows that predominant adsorption of organic pollutants was governed by π-π stacking, with a minor role of hydrogen-bonding on the biochar surface. In summary, higher pyrolysis temperature biochar yielded greater adsorption capacity greywater borne contaminants and the reaction temperature (10–34 °C) and presence of anionic surfactant had a limited effect on the adsorption of organic pollutants, suggesting efficacious application of biochar in general for greywater treatment in nature-based systems.

Prediction competitive multi-ions leaching under various flow chemistry conditions: Column studies and unified thermodynamic-kinetic modeling

Current models for inorganic ion transport in porous media describe the adsorption–desorption processes mostly based on empirical adsorption isotherms or simple thermodynamic mechanisms, often overlooking the adsorption kinetics. This study introduces a novel unified reactive solute transport model framework that incorporates well-established surface complexation models to describe the adsorption–desorption of ions in the transport process and takes into full consideration the non-equilibrium adsorption, enabling the use of the same set of thermodynamic-kinetic parameters to accurately describe ion transport under different chemical conditions. To evaluate the constructed model, Cr(VI), P(V), and As(V) column transport experiments were carried out using goethite-coated sand as the porous medium. Kinetic constants derived from single-ion transport experiments accurately predicted the cotransport behaviors of Cr(VI), P(V), and As(V) under various flow chemistry conditions, especially the overshooting phenomena of Cr(VI) under P(V) and As(V) competition. The model framework can be easily incorporated into solute transport models with various surface complexation reactions to predict the fate and transport of ions under complexed chemical conditions without extensive parameterization, and thus is a useful complement to the current reactive transport model.

Synthesis and utilization of green metal oxide polymeric nanocomposite for removal of Red-XGRL dye from aqueous solution: batch and column study

Synthesis and utilization of green metal oxide polymeric nanocomposite for removal of Red-XGRL dye from aqueous solution: batch and column study

Three-dimensionally printed scaffold coated with graphene oxide for enhanced heavy metal adsorption: Batch and fixed-bed column studies

In this study, a poly-lactic acid (PLA) filter coated with graphene oxide (GO) was three-dimensionally (3D) printed as a novel heavy metal adsorbent (particularly cadmium (Cd)) in an aqueous system. The PLA filter was extruded using the fused deposition modeling 3D printing technique, and the GO/PLA filter was prepared by simple dip coating after acetone pretreatment. The study of the adsorption of Cd onto the GO/PLA filter showed that the kinetic and isotherm experimental results were positively correlated with the pseudo-second-order equation and Langmuir model. The maximum adsorption capacity of the GO/PLA filter for Cd by Langmuir model was 1.26 mg/g. The filter could be regenerated for five repeated cycles using acid and sonication. Additionally, a continuous fixed-bed column was constructed using the GO/PLA and neat PLA filters. The Cd concentration profile was fitted to the Thomas model. The column containing the GO/PLA filter could be operated up to 1250 h until the saturation point (C0 = Ct), whereas that containing the neat PLA filter could only be used for 15 h. The GO/PLA filter also effectively adsorbed other cationic heavy metals through electrostatic attraction and strong surface complexation with oxygen-containing groups in GO. The utilization of the GO/PLA filter demonstrated not only the effective immobilization of the powdery adsorbent onto the PLA surface but also showcased the adaptability of the 3D-printed adsorption filters to water treatment.

Polymeric ferrite composites as versatile adsorbents for enhanced reactive blue dye removal: a promising solution for treating textile wastewater

ABSTRACT Water contamination caused by the increasing industry and urbanisation is one of the most significant environmental problems that entire planet is facing. Various polymeric ferrite composites synthesised in the current study were employed to remove the synthetic reactive dye blue-248 from wastewater. The polymeric ferrite composites were characterised using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transmission infrared spectroscopy (FTIR) to observe the surface morphology, crystallinity and chemical structure of as-prepared composites. The optimum removal of dye using Ni-CoFe2O4/Chitosan, Zn-NiFe2O4/Starch, CoNiZnFe2O4/Polyaniline, Ni doped CrZnFe2O4/Alginate, Cr doped ZnCoFe2O4/PVA was at (i) pH 2 (32.34 mg/g), 3 (30.31 mgg−1), 3 (21.05 mgg−1), 3 (25.69 mgg−1) and 4 (38.61 mgg−1), (ii) optimum dose (0.03 mg/g) 32.40, 30.27, 21.91, 25.98 and 39.2 mg/g, (iii) Contact time (6090 min) 46.898, 37.70, 43.318, 29.356 and 34.12 mg/g, (iv) Initial dye concentration 32.24 mgg1, 25.79 mgg−1 (120 mg/L), 35.85 mgg−1, 28.37 mgg−1 and 40.37 mgg−1 (150 mg/L) and (v) temperature (65°C) 29.67, 27.08, 21.66, 23.60 and 41.40 mg/g, respectively. Different equilibrium, kinetic and thermodynamic models were used to check the nature of sorption, reaction rate/order of reaction and feasibility of reaction, respectively. The effect of presence of various electrolytes, different metals and surfactants in wastewater were also studied. For dye removal on a large scale, the effects of bed height (1–3 cm), flow rate (1.8–5.4) and initial dye concentration (50–90 ppm) were examined in column study. Different eluents were used for the desorption study of reactive dyes to check the reusability of process.

In-situ growth of Al/Ni layered double hydroxide onto polyaniline-wrapped sisal fibers for highly efficient removal of pharmaceutical Ketoprofen and Ibuprofen contaminants: Batch and fixed-bed column studies

The present study focuses on the in-situ growth of Al/Ni layered double hydroxide onto polyaniline/sisal fibers (SF/PANI/LDH). The main purpose is investigating the effectiveness of this composite material in removing non-steroidal anti-inflammatory artificial pharmaceutical contaminants (ketoprofen (KTP) and ibuprofen (IBP)). The present investigation involves conducting batch and fixed-bed column experiments. Various analytical techniques, namely SEM, FTIR, and XRD, were conducted to analyze prepared adsorbent features. These analyses indicated that Al/Ni layered double hydroxide was successfully coated on the polyaniline-wrapped sisal fibers. The batch study was mainly focused on assessing influencing parameters (solution pH, adsorbent dosage, pollutant concentration, and time), equilibrium curves, kinetic behavior, and the determination of thermodynamic parameters. In particular, the findings illustrate that adsorption results were well correlated to the pseudo-second-order kinetic and Temkin isotherm models, in which the maximum adsorption capacities for IBP and KTP were measured to be about 86.03 and 38.68 mg/g, respectively. The adsorbent showed having an acceptable efficiency even after six cycles of regeneration, where adsorption capacity decreased <15 % compared to primary adsorbent. In addition, the fixed-bed column study was conducted, and the results revealed that the service volume reduced with the increase in the flow rate.

Crack Resistance of RC Columns Strengthened By CFRP Under 30% of Uls Loading

Abstract Nowadays, among many existing reinforced concrete (RC) columns, it is impossible to find samples that work only as centrally compressed members – their vast majority work as eccentrically compressed members. On the other hand, the significant volumes of reconstruction in Ukraine will require studies of the work of various RC structures strengthened under different load levels. In addition to choosing the method of strengthening itself, the relevant tasks will be studies of bearing capacity, crack resistance, reliability (including residual resource) of structures, etc. This article presents the method of crack resistance experimental study of eccentrically compressed RC members. The proposed method was tested on unstrengthened (ordinary) and strengthened (in a stretched zone) RC columns; the results of experimental studies for ordinary and strengthened samples were also obtained. The columns were strengthened with a composite material (from many carbon-fiber-reinforced polymers) – the Sika Carbodur S512 strip. The feature of the crack resistance study of columns was that they were strengthened under the initial load level of 30 %. As a result of experimental research on the samples strengthened under load, we stated that the width of the crack decreased on average by about 36 % (at the comparable values of the active load). In turn, the average maximum length of cracks decreased to about 50 % of the height of the cross-section (for unstrengthened samples, this value was approximately 80 %), and the eccentric compressive ultimate load was increased by about 33 %.

Designer biochar with specific functionalities for the sustainable mining of invaluable metals from sea water: Performance assessment, mechanism insights and cost benefit analysis

Resource efficiency and cleaner production are an integral component of sustainable development. The present research addresses three contemporary issues. Firstly, quest for a greener alterative to land based mining-seawater, secondly, translation of renewable biowastes into carbon negative biochar and thirdly, synthesis of organic salts of metals directly from metal laded biochar. Sea water is an untapped source of invaluable elements leading to rising momentum for various new technologies. Herein, neem cake is tailored specifically for selective recovery of magnesium and strontium ions from simulated sea water in both batch and continuous systems. Magnesium selective biochar is prepared by insitu pyrolysis at 700℃ using sodium bicarbonate and urea as green porogen and nitrogen source whereas strontium selective biochar is prepared by direct pyrolysis at 700℃ followed by encapsulating alginate microspheres within the biochar lattice. Batch studies revealed the maximum adsorption capacities and removal efficiencies of 34.08 mg/g and 95 % for strontium(S-BC) and 40.2 mg/g and 98 % for magnesium(M−BC). The analytics reveals biochars as fine-tuned mesoporous carbon dominant structure with several N and O functionalities suggesting complexation, H-bonding as the adsorption mechanism. The Sips and PNO models surpassed all isotherm and kinetic models and well describes the process kinetics as chemisorption along with film diffusion as main contributors respectively. In column studies, effect of different process parameters is investigated and it is observed that experimental data corelates well with the BDST model. Moreover, scale up approach is employed to predict large scale design parameters. Lastly, citric acid as a green chelating agent is utilized to recover metal ions in the form of citrates and regenerate spent biosorbent along with detailed cost benefit analysis, thereby endorsing the circular economy approach.

Fabrication of biocompatible chitosan/graphene based nanocomposite for the competitive adsorption of heavy metal ions from wastewater in binary and ternary systems: Scale-up and upgradation studies

Coexistence of multiple metal ions in the wastewater alters the adsorption behavior compared to single metal ion system using the existing adsorbents which are chemically driven, requires harsh operating conditions and additional energy. The present study evaluates the performance of Chitosan/Graphene based nanocomposite for the competitive adsorption of heavy metals in single, binary and ternary systems. Maximum removal efficiency was 89.35 % (As), 90.41 % (Cu), 93.22 % (Ni), 96.47 % (Cd), 95.45 % (Pb) and 88.65 % (Cr) under optimum conditions (pH 4, Temperature = 25 °C, Equilibrium Time = 90 min, Adsorbent Dosage = 1.25 g and Initial Metal Ion Concentration = 150 mg/L) in a single system. A detailed investigation on the competitive adsorption of Cadmium, Copper, and Chromium ions was performed in binary. Maximum adsorption capacity was 1.55 mg/g and 1.48 mg/g (CuCd); 2.98 mg/g and 3.21 mg/g (CuCr) and 2.21 mg/g and 1.90 mg/g (CdCr system) at 4 mM concentration. The constructed mathematical models accurately forecast the adsorption behavior and shows a good match with the experimental data. Also, fixed-bed column studies were performed for the large-scale upgradation and optimum flow rate and bed height was 1 L/h and 15 cm at 25 °C. The study proposes the fabrication of natural-polymer based composite which can significantly reduce the dependency on synthetic and chemical-based adsorbents which poses severe negative impacts such as high-cost, poor selectivity and rapid saturation due to their low recyclability or sludge generation. Such application can effectively transform wastewater into contamination free water that could be valuable to society.

Pyrrhotite-sulfur-limestone composite for high rate nitrogen and phosphorus removal from wastewater: Column study

Pyrrhotite-sulfur-limestone composite (PSLC) was prepared and PSLC autotrophic denitrification biofilter (PSLCAD) was constructed with PSLC particle (2–4.75 mm) in this study. During treating synthetic, municipal and industrial secondary effluent, PSLCAD showed good NO3−-N and PO43--P removal, and the highest TON (Total oxidized nitrogen) removal rate of PSLCAD was up to 1749.91 mg/L/d. At HRT 0.5 h, and influent NO3−-N 21.09 mg/L, TON removal rate was up to 1005.12 mg/L with effluent NO3−-N 0.10 mg/L. PSLCAD achieved effluent PO43--P below 0.2 mg/L when influent PO43--P was around 0.5 mg/L. HRT down to 0.5 h had no negative impacts on N removal. Effluent pH below 7 was harmful to denitrification performance of PSLCAD. TON removal rate increased with influent NO3−-N increasing, but influent NO3−-N over 103.55 mg/L decreased NO3−-N removal rate. In PSLCAD biofilter, the most dominant bacteria were Thiobacillus and Sulfurimonas, and they played the most important role in denitrification, but the abundance of heterotrophic denitrifiers was also quite high. PO43− was mainly removed through precipitate of Fe–P in PSLCAD. The synergistic effects between pyrrhotite and sulfur autotrophic denitrification were much enhanced, and that caused PSLCAD to achieve high rate N and P removal.

Kinetic and equilibrium study of graphene and copper oxides modified nanocomposites for metal ions adsorption from binary metal aqueous solution.

Presently, the main cause of pollution of natural water resources is heavy metal ions. The removal of metal ions such as nickel (Ni2+) and cadmium (Cd2+) has been given considerable attention due to their health and environmental risks. In this regard, for wastewater treatment containing heavy metal ions, graphene oxide (GO) nanocomposites with metal oxide nanoparticles (NPs) attained significant importance. In this study, graphene oxide stacked with copper oxide nanocomposites (GO/CuO-NCs) were synthesized and characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and atomic force microscopy (AFM) analytical procedures. The prepared GO/CuO-NCs were applied for the removal of Ni2+ and Cd2+ ions from a binary metal ion system in batch and continuous experiments. The obtained results revealed that GO/CuO-NCs exhibited the highest removal efficiencies of Ni2+ (89.60% ± 2.12%) and Cd2+ (97.10% ± 1.91%) at the optimum values of pH: 8, dose: 0.25g, contact time: 60min, and at 50ppm initial metal ion concentration in a batch study. However, 4mL/min flow rate, 50ppm initial concentration, and 2cm bed height were proved to be the suitable conditions for metal ion adsorption in the column study. The kinetic adsorption data exhibited the best fitting with the pseudo-second-order model. The adsorption isotherm provided the best-fitting data in the Langmuir isotherm model. This study suggested that the GO/CuO nanocomposites have proved to be efficient adsorbents for Ni2+ and Cd2+ ions from a binary metal system.

Aluminium dross waste utilization for phosphate removal and recovery from aqueous environment: Operational feasibility development

The need to minimize eutrophication in water bodies and the shortage of phosphate rock reserves has stimulated the search for sequestration and recovery of phosphate from alternative sources, including wastewater. In this study, aluminium dross (AD), a smelting industry waste/by-product, was converted to high-value material by encapsulation in calcium alginate (Ca-Alg) beads, viz. Ca-Alg-AD and utilized for adsorptive/uptake removal and phosphate recovery from an aqueous environment. Encapsulation of AD in alginate beads solves serious operational difficulties of using raw AD material directly due to density difference constraining efficient contact of AD with pollutants present in water and post-treatment recovery of AD material. The phosphate removal was evaluated in both batch and continuous flow operation modes. The batch adsorption study revealed 96.86% phosphate removal from 10 mg L−1 of initial phosphate concentration in 70 min of optimal contact time. Further, the phosphate removal potential of Ca-Alg-AD beads turned out to be independent of solution pH, with an average of 95.93 ± 1.40 % phosphate removal in the 2–9 pH range. The result reflects phosphate adsorption on Ca-Alg-AD beads following a second-order pseudo-kinetic model. Ca-Alg-AD beads-based adsorption followed Freundlich and Langmuir isotherm models. Further, a continuous packed bed column study revealed a total phosphate adsorption capacity of 1.089 mg g−1. The chemical composition, physical stability, and surface properties of Ca-Alg-AD beads were analyzed by means of state-of-the-art analytical techniques, such as Scanning Electron Microscopy-Energy Dispersive X-ray spectroscopy (SEM-EDX), Fourier Transform Infrared Spectroscopy (FTIR) and thermogravimetry/Differential Thermal Analysis (TG/DTA). These characterization techniques comprehend the mechanism and influence of surface properties and morphology on the phosphate adsorption behaviour, which induce the involvement of multiple mechanisms such as ligand complexation, ion exchange, and electrostatic attraction for phosphate adsorption on Ca-Alg-AD beads.

Effective triclosan removal by using porous aromatic frameworks in continuous fixed-bed column studies.

Triclosan (TCS) has been regarded as an emerging contaminant in aquatic systems, making its efficient removal of great significance. In this study, NPVMo@iPAF-1, with a specific surface area of 665 m2/g, was prepared by incorporating (NH4)5H6PV8Mo4O40 into porous aromatic frameworks (PAF). The maximum adsorption capacity of TCS on NPVMo@iPAF-1 reached 917.1mg/g, as calculated from the Langmuir model. Fixed-bed columns packed with NPVMo@iPAF-1 were employed for TCS removal; the experiment data strongly correlated with the Thomas and Yoon-Nelson models under different operational conditions. Pore preservation, electrostatic effects, and the synergistic effect of π-π interactions contributed to the effective adsorption of TCS onto NPVMo@iPAF-1. The NPVMo@iPAF-1 fixed-bed column could be effectively regenerated through in-situ ozonation for more than 10 regeneration cycles. NPVMo@iPAF-1 turned out to be a promising adsorbent for removing TCS not only from pure water but also from reclaimed water and surface water samples.