Porous Beads Research Articles

Development and validation of novel automatable assay for cholesterol efflux capacity.

During the past decade, evaluation of high-density lipoprotein (HDL) functionality has been well studied for predicting cardiovascular disease risk. Cholesterol efflux capacity (CEC) is the strongest candidate as the biomarker out of various HDL anti-atherosclerotic functions. However, CEC has not yet been introduced clinically because of several technical issues, including the use of radioactive materials and differentiated cells in the assay. Previously, our laboratory developed a radioisotope- and cell-free CEC assay called the immobilized liposome-bound gel beads (ILGs) method to replace the conventional method. However, the separation process of the supernatant was not suitable for installation in an automatic analyzer. This study aims to develop a new method that is easier to operate. We assumed that the use of magnetic beads instead of gel beads would enable the skip of the centrifugal process. First, similar to the ILG method, porous magnetic beads were treated with liposomes containing fluorescently labeled cholesterol. Fluorescence was observed inside the magnetic beads, and almost the same amount of liposomes as in the ILG method was immobilized successfully. These immobilized liposome-bound magnetic beads (ILMs) were available for CEC assay when HDL and apolipoprotein B-100 depleted serum were used as cholesterol acceptors. The ILM method showed sufficient basic performance and a good correlation with the ILG method. Furthermore, when the CEC of 15 serum samples from healthy subjects was measured, a good correlation between HDL-cholesterol level and the ILG method was confirmed. Thus, it was confirmed that the ILM method was successfully developed and could be automated.

Porous titania beads for remediation of arsenic contamination from acid mine drainage

Hierarchically porous titania beads with and without amine functionalisation have been developed and tested as adsorbents for removal of highly toxic As(V) from environments affected by acid mine drainage (AMD). The unique acid stability of the titania framework enables these adsorbents to function in highly acidified environments and their granular form facilitates practical deployment under continuous flow conditions. Herein, both non-functionalised and amine-functionalised titania beads have been demonstrated to selectively remove As(V) from simulated and real AMD solutions at pH 2.6. Novel selectivity for As(V) over Na(I), Mg(II), Al(III), Si(VI), Ca(II), Co(II), Cu(II), Zn(II), Nd(III) and Ho(III) was achieved, with competing element concentrations similar to or up to an order of magnitude greater than that of As(V). Although Fe(III) and some Fe(II) were also adsorbed by the titania beads, Fe adsorption did not inhibit As(V) adsorption, indicating different adsorption mechanisms for these two elements. The As(V) adsorption capacity of the titania beads decreased from ∼20 mg/g from pure As(V) solution to ∼10 mg/g from real AMD solution, demonstrating the importance of adsorbent testing under applied conditions. Amine functionalisation increased the kinetics of adsorption, but the non-functionalised titania beads showed greater selectivity for As(V) over Fe(II) and Fe(III) and hence were considered preferable for As remediation applications. Nevertheless, the functionalisation ability of the porous titania beads makes them a promising, flexible technology for remediation of a wide range of AMD affected environments.

Highly selective and easily regenerated novel PVDF/KCTS porous beads for the sustainable removal of cesium from wastewater

Removing 137Cs from nuclear wastewater with abundant coexisting ions at low concentrations has always been meaningful and challenging. This work synthesized a novel adsorbent K1.9Cr0.2Sn2.79S7 (KCTS) for the first time by Cr-doping using a two-dimensional [Sn3S7]n2n− anion layer as a template. The stability and adsorption performance of the doped materials were significantly enhanced. The powder material (KCTS) was coated with PVDF to obtain the composite microspheres, facilitating its industrial application. The optimized PVDF/KCTS microspheres reached adsorption equilibrium within 40 min with an adsorption capacity of 402.86 mg g−1 and exhibited broad acid-base tolerance and superior selectivity. Subsequently, the PVDF/KCTS microspheres were placed in the Cs-containing geothermal water to simulate the Cs removal process. The distribution coefficient of Cs+ is as high as 11627.91 mL g−1 and the separation factors (αMCs) between Cs+ and other ions ranged from 403.22 to 1120.22. In addition, efficient regeneration of the adsorbent was achieved through the elution of NaNO3.The adsorption performance did not attenuate notably after 10 cycles. PVDF/KCTS is a novel composite adsorbent that can be used for large-scale Cs removal and enrichment in wastewater.

Atrazine biodegradation in water by co-immobilized Citricoccus sp. strain TT3 with Chlorella vulgaris under a harsh environment

With the extensive use of herbicides in agricultural production, the nearby waters are polluted by atrazine. The isolated Citricoccus sp. strain TT3 in our lab can transform atrazine into harmless cyanuric acid under natural conditions. However, this method is limited in practical use because of the weak resistance of bacteria to the harsh water environment. To solve this problem, Chlorella vulgaris was combined with atrazine degradation bacteria and co-immobilized in porous beads. The results demonstrated no significant difference in the atrazine removal rate between the free bacteria-microalgae mixture and the pure bacteria sample. Only 3.15 % and 4.35 % of atrazine in the acidic solution were removed by free bacteria and the bacteria-algae mixture. However, the degradation rate of immobilized bacteria and co-immobilized bacteria-microalgae under the same condition increased by 22.93 % and 40.57 %, respectively. Moreover, the inhibition effect of concomitant Mn2+, Cd2+, Co2+, and Cu2+ on the activity of Citricoccus sp. strain TT3 in beads was reduced. In addition, the long-term storage of immobilized beads still maintained a relatively stable degradation capacity, but its reusability needed to be improved. After being entrapped in microspheres, the enhancing effect of Chlorella vulgaris on the biodegradation of atrazine was pronounced under adverse environmental conditions. The study provided insight into the practical application of atrazine biodegradation technology.

Quaternization of Porous Cellulose Beads and Their Use for Removal of Humic Acid from Aqueous Medium

Porous cellulose beads were quaternized with glycidyltrimethylammonium chloride (GTMAC) to explore a potential use of them as an adsorbent for removal of humic acid (HA) from aqueous medium. The introduction of quaternary ammonium groups was confirmed by FT-IR and XPS analysis. The content of introduced quaternary ammonium groups increased with an increase in the GTMAC concentration. The adsorption capacity increased with a decrease in the initial pH value and attained the maximum value at pH 3 and increased with an increase in the content of quaternary ammonium groups. The removal % increased with the dose of quaternized cellulose beads at both pH 3.0 and 6.0. The adsorption process obeyed the pseudo-second order kinetic model and exhibited a better fit to the Langmuir isotherm model, suggesting that the adsorption of HA is accomplished through the electrostatic interaction between a quaternary ammonium group introduced and a dissociated carboxy group of a HA molecule. The maximum adsorption capacity obtained in this study is comparable to or higher than those published by other articles. HA loaded was completely released to NaOH solutions at higher than 100 mM to regenerate the quaternized cellulose beads. The above-mentioned results clearly show that the quaternized cellulose beads prepared in this study can be used as a regenerable adsorbent with high capacity for removal of HA from aqueous medium.

Purification of lipase from Burkholderia metallica fermentation broth in a column chromatography using polymer impregnated resins

In this work, porous glass beads grafted with polyethylene glycol (PEG) were used as an adsorbent to purify lipase from Burkholderia metallica in column chromatography. The purification parameters viz. salt stability, types and concentrations of PEG and salt, pH of the binding solution, and flow rate were studied to determine the performance of the purification system in an XK16/20 column. The crude lipase was mixed with different types and concentrations of salts 1–5% (w/w) (sodium citrate, potassium citrate, and sodium acetate) and subjected to the column containing the polymeric glass bead. One-variable-at-a-time experimentation revealed that 20% (w/w) PEG 6000 g/mol impregnated glass beads with a binding solution of 5% sodium citrate at pH 7.7, a flow rate of 1.0 mL/min and extraction time of 10 min resulted in the highest purification factor and recovery yield at 3.67 and 88%, respectively. The purified lipase has 55 ∼ 60 kDa molecular mass. The outcome of the study showed PEG could be applied to modify the inert glass beads into polymeric form, providing a biocompatible and mild separation condition for lipase. Thus, PEG could be successfully applied for the purification of lipase from B. metallica fermentation broth using column chromatography.

Poly(vinyl alcohol)/modified porous starch gel beads for microbial preservation and reactivation: preparation, characterization and its wastewater treatment performance.

Poly(vinyl alcohol) (PVA)/modified porous starch (MPS) gel beads were prepared through in situ chemical cross-linking by incorporating with MPS, which was obtained by modifying porous starch (PS) with polyethyleneimine (PEI) and glutaraldehyde (GA). Addition of MPS could improve the storage modulus and the effective crosslinking density (ve) of the gel beads, and the mechanical properties were enhanced. The PVA-MPS gel beads were preserved as immobilized microbial carriers for 40 d and reactivated in wastewater. Scanning electron microscope (SEM) observations showed that the beads were highly porous and conducive for microorganism adhesion. The PVA-MPS gel beads were able to remove 97% of ammonia nitrogen and 80% of chemical oxygen demand (COD) after reactivation under all four preservation conditions. The abundance of Hydrogenophaga as denitrifying bacteria on PVA-MPS gel beads increased, with abundance of 8.44%, 5.55%, 8.90% and 9.48%, respectively. It proved that the carrier provided a partial hypoxic environment for microorganisms.

Binderless SAPO-34 beads for selective CO2 adsorption

Selective adsorption of CO2 from biogas allows isolating biomethane, which can then be used as a direct substitute for natural gas. The microporous zeotype SAPO-34 is a suitable material for CO2 adsorption because it can achieve high working capacity at relatively mild regeneration conditions. In industrial applications, adsorbents need to be shaped into a macroscopic format (e.g. beads, pellets) in order to reduce the pressure drop over the adsorption column. Typically, an inert binder is added to the powder to achieve the desired format. In this work, novel hierarchically porous binderless SAPO-34 beads with a diameter in the range 0.7–1.2 mm were synthesised employing an ion-exchange resin as a hard template. The interior of the beads consisted mostly of small SAPO-34 crystals (< 0.3 μm) interconnected to each other and thus generating a network of meso‑ and macropores between them, as demonstrated by XRD and SEM. Around several of the beads, a crystal overgrowth was observed consisting mostly of larger SAPO-34 crystals (1–25 μm). The SAPO beads displayed good CO2 adsorption capacity (3.0 mmol g−1 at 1 bar), which was higher than that of binder-containing SAPO-34 extrudates (2.4 mmol g−1 at 1 bar), but slightly lower compared to SAPO-34 in powder format (3.4 mmol g−1 at 1 bar). Furthermore, the SAPO-34 beads displayed high CO2/CH4 selectivity (8, at partial pressures mimicking biogas, i.e. 0.4 bar CO2 and 0.6 bar CH4) as well as high CO2/N2 selectivity (33, at partial pressures mimicking flue gas, i.e. 0.15 bar CO2 and 0.85 bar N2). Notably, a high CO2 working capacity of 1.8 mmol g−1 was estimated based on the adsorption isotherm between 1 and 0.2 bar, and this value has the potential to be further improved by increasing the adsorption pressure to > 1 bar.

Development of composite panels based on porous glass aerogels for acoustic applications

In this work, we present the results of research on manufacturing composite materials based on porous glass beads for acoustic treatment. A new material with fire resistance, heat resistance, impermeability, longevity, and insulation is made from foam glass beads (made from waste glass) and cement mortar. Firstly, the composite concrete panels with a high level of porosity 66%–82% and spherical pores in millimeter scale (i.e., ranging from 0.15mm to 10mm) are fabricated. Then, acoustical measurements are performed to characterize the sound absorbing coefficient and the transport properties of the selected composite panels. The measurement data are compared to the semi-phenomenological Johnson-Champoux-Allard-Lafarge model to show a good agreement in terms of predicting the sound absorption property. From the obtained results it can be stated that the open porosity and the thickness of the fabricated materials affect strongly their sound absorption performance. Within a panel thickness of 33.3mm, the aerogel-based concrete panel can provide a good sound absorption coefficient which could be more than 0.60 in the frequency range of [820 1290]Hz and reach the value of 0.84 at a low resonance frequency of ~1032Hz. The methodology, therefore, enables the identification and validation of acoustical models for specific porous glass aerogel-based materials and paves the way for an efficient exploration of the parameter space for acoustical materials design.

Green Synthesis of Hierarchically Porous Alginate/ZIF‐8 Composite Beads for Water Treatment

AbstractThe immobilization of powdery metal‐organic‐frameworks (MOFs) into porous matrix has risen to be a promising approach for their practical applications. This work presents the green synthesis of porous alginate/ZIF‐8 composite beads through the in situ growth of ZIF‐8 in alginate hydrogel beads crosslinked by Zn2+ and subsequent freeze‐drying process, during which only water is used as reaction solvent. The macro‐ and meso‐pores in alginate matrix and micro‐pores in immobilized ZIF‐8 endow the porous composite beads with hierarchically porous structure, which benefits their adsorption properties. Methylene blue (MB) is selected as probe molecule to assess the adsorption performance of the porous composite beads toward water contaminants. It is found that the growth time of ZIF‐8 has a significant influence on the adsorption performance, and the calculated maximum adsorption capacity of ZIF‐8@Alg30 for MB reaches 628.93 mg g−1 at 298 K. Additionally, the adsorption process fits well with the pseudo‐second‐order kinetic model and Langmuir isotherm model, and the adsorption process is found to be spontaneous, endothermic and irreversible based on thermodynamic studies.

In vitro evaluation of antibacterial activity and biocompatibility of synergistically cross-linked gelatin-alginate hydrogel beads as gentamicin carriers

This work aimed to develop biodegradable millimeter-scale spherical hydrogel beads with highly interconnected pores, which effectively serve dual functions for cell growth and antibiotic release. Sodium alginate and gelatin were used as the matrix for the hydrogel beads, which were synergistically cross-linked by using different ratios of the cross-linkers N-ethyl-N-(3-dimethylaminopropyl) carbodiimide and calcium chloride. Spherical porous hydrogel beads after sucrose leaching were prepared with particle sizes of 2–3 and 4–6 mm. Their physicochemical properties, including pore size, surface and cross-sectional morphology, degree of crosslinking and free amines, swelling, and degradation, were measured. Selected 2–3 mm hydrogel beads were further impregnated with gentamicin and analyzed for biocompatibility and antibacterial activity. The results showed that the synergistically cross-linked hydrogel was an internally porous structure with a porosity of about 80% and a uniform pore size distribution between 90 and 212 μm, with no significant difference in the average pore size of 160 μm for all beads. After soaking for 24 h, the beads absorbed approximately 50 times their weight (w/w) while maintaining a stable pore size without significant swelling. The cross-linker concentration of carbodiimide/CaCl2 was chosen to be 1/0.5 wt% to reduce the cytotoxicity that might be caused by the release of Cl ions. The polar interaction of the hydrogel with gentamicin accelerate the degradation of the beads after impregnation with the antibiotic gentamicin, resulting in a burst release of the antibiotic. Therefore, the gentamicin-impregnated hydrogel beads had better antibacterial activity compared with the hydrogel without antibiotics. However, these gentamicin-impregnated beads had reduced resistance to hydrogel degradation and biocompatibility. The developed hydrogel beads had good antibacterial activity and can be used in combination with different medical devices to further improve biocompatibility and reduce the risk of surgical failure caused by infection.

Radially aligned hierarchical N-doped porous carbon beads derived from oil-sand asphaltene for long-life water filtration and wastewater treatment

The application of waste-derived highly efficient adsorbent for organic pollutants removal from water and wastewater is presented. Highly porous carbon beads with radially aligned macrochannels were prepared from asphaltene. Well-ordered inwardly aligned macrovoids favored solute diffusion and maximized the liquid accommodation capacity. A further N-doping could modulate the sorbent hydrophilicity leading to an outstanding absorption performance for a range of organic solvents and oily chemicals. N-doped carbon beads were effective sorbents of lopinavir (LNV) and ritonavir (RNV) from water and wastewater. The process of sorption was fast, and the highest removal was noted for RNV than LPV. N-doping favored LNV and RNV adsorption due to the increased porous structure of N-doped asphaltene beads. The chemisorption of both LPV and RTV was a rate-limiting step. The presence of co-pollutants in treated wastewater enhanced LPV and RNV removal and an up to 470 % increase was noted. The presence of LPV or RTV in distilled water was not toxic to Aliivibrio fischeri or even can stimulate their growth. However, after the adsorption process, the solution of RTV reduced its toxicity significantly and the final solution was not toxic. The opposite effect was noted for LPV. Given the repeatability, high removal performance, and cost-effectiveness of the asphaltene-based carbon microtubes when compared to other well-known sorbents such as carbon nanotubes, they demonstrated great potential as a low-cost and effective agent for long-life water filtration and wastewater treatment.

Monodisperse Porous Silica/Polymer Nanocomposite Microspheres with Tunable Silica Loading, Morphology and Porosity

Hybrid organic/inorganic nanocomposites combine the distinct properties of the organic polymer and the inorganic filler, resulting in overall improved system properties. Monodisperse porous hybrid beads consisting of tetraethylene pentamine functionalized poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) particles and silica nanoparticles (SNPs) were synthesized under Stoeber sol-gel process conditions. A wide range of hybrid organic/silica nanocomposite materials with different material properties was generated. The effects of n(H2O)/n(TEOS) and c(NH3) on the hybrid bead properties particle size, SiO2 content, median pore size, specific surface area, pore volume and size of the SNPs were studied. Quantitative models with a high robustness and predictive power were established using a statistical and systematic approach based on response surface methodology. It was shown that the material properties depend in a complex way on the process factor settings and exhibit non-linear behaviors as well as partly synergistic interactions between the process factors. Thus, the silica content, median pore size, specific surface area, pore volume and size of the SNPs are non-linearly dependent on the water-to-precursor ratio. This is attributed to the effect of the water-to-precursor ratio on the hydrolysis and condensation rates of TEOS. A possible mechanism of SNP incorporation into the porous polymer network is discussed.

Porous alginate hydrogel beads cross-linked with citric acid containing tannic acid: structural analysis, antimicrobial properties and release behavior

Porous alginate hydrogel beads cross-linked with citric acid containing tannic acid: structural analysis, antimicrobial properties and release behavior

Highly selective and easily regenerated novel porous polyacrylonitrile-ammonium phosphomolybdate beads for cesium removal from geothermal water

A novel porogen-added ammonium phosphomolybdate-polyacrylonitrile (AMP-PAN-N20) was prepared to remove Cs+ from geothermal water. Compared with traditional AMP-PAN, porous AMP-PAN-N20 beads have a smaller particle size, larger adsorption capacity and faster adsorption rate. The adsorption batch experiments were carried out with the research objects' adsorbent contact time, dosage, pH value, initial Cs+ concentration, temperature and competing ions. The results showed that AMP-PAN-N20 could effectively adsorb Cs+ in a wide pH range and high concentration of competing ions. Remarkably, the adsorption performance hardly decreased after ten cycles of adsorption. In addition, the column adsorption tests were obtained using Cs-containing geothermal water. The results showed that the adsorption breakthrough time could be as long as 60 h (flow rate Q = 2 mL·min−1, bed height H = 8 cm), and the maximum dynamic adsorption capacity was 25.62 mg·g−1 under the Thomas model. In addition, the AMP-PAN-N20 maintained good stability after a long time of adsorption.

Effect of Porous Catalyst Support on Plasma-Assisted Catalysis for Ammonia Synthesis.

We report on the effect of catalyst support particle porosity on the conversion of NH3 synthesis from N2 and H2 in a coaxial dielectric barrier discharge (DBD) plasma reactor. The discharge was created using an AC applied voltage with the reactor at room temperature and near atmospheric pressure (550 Torr). Two different particles of almost equal diameter (∼1.5 mm)─porous silica (SiO2) ceramic beads (average pore size: 8 nm) and smooth, nonporous soda lime glass beads─were compared in the DBD reactor. As the pore size in the SiO2 particles was smaller than the Debye length, penetration of the plasma into the pores of the particles was unlikely; however, reactive species generated in the plasma outside the particles could diffuse into the pores. The N2 conversion and energy yield of NH3 increased with applied voltage for both particle types, and these values were consistently higher when using the SiO2 beads. Discharge and plasma properties were estimated from Lissajous plots and using calculations with the BOLSIG+ software. The effect of these two different catalyst supports on the physical properties of the discharge was negligible. High resolution optical emission spectra revealed that the concentrations of N2+, atomic N, and atomic H (Hα, Hβ) in the plasma discharge were lower with the porous SiO2 beads than with the glass beads at every applied voltage tested. This indicates that these active species participate in heterogeneous reactions at support particle surfaces and that the larger surface area presented by the porous particles led to higher rates of depletion of these intermediates and a higher rate of ammonia synthesis.

Generation of porous starch beads via a 3D food printer: The effects of amylose content and drying technique

A new approach via extrusion-based 3D food printing (3DP) was developed to fabricate porous spherical beads from corn starches with different amylose contents (i.e., 25, 55, and 72 %). The effects of amylose content and drying method, i.e., freeze-drying and supercritical carbon dioxide (SC-CO2), on the structural properties of the starch beads were investigated. The shape and size of the 3D-printed beads highly depended on the starches' amylose content as it affected the rheological properties of the inks. The smallest 3D-printed bead size was ∼980 μm generated from high amylose (72 %) corn starch. 3DP of starch with high amylose content along with SC-CO2 drying resulted in starch beads with superior properties. The SC-CO2-dried beads showed a significantly higher surface area (175 m2/g) than the freeze-dried ones (<1 m2/g).

Graphene oxide incorporated cellulose acetate beads for efficient removal of methylene blue dye; isotherms, kinetic, mechanism and co-existing ions studies

In this investigation, new porous adsorbent beads were formulated via the incorporation of graphene oxide (GO) into cellulose acetate beads (CA) for the adsorptive removal of methylene blue (MB) dye. The experimental results signified that the adsorption of MB dye increased with the increase in the GO ratio from 10 to 25%. In addition, the adsorption process obeyed PSO kinetic model and Langmuir isotherm model with a maximum adsorption capacity reaching 369.85 mg/g. More importantly, it was proposed that the adsorption mechanism of MB dye onto GO@CA proceeded via electrostatic interactions, H-bonding, van der Waals forces, n-π and π -π interactions. Besides, the fabricated beads exhibited an excellent ability to recycle and reuse after five successive cycles. In addition, there was a high selectivity of GO@CA beads towards MB molecules in the presence of co-existing cations such as Fe2+, Zn2+, Cu2+ and Ni2+.

Incorporation and influence of natural gums in an alginate matrix for Serratia plymuthica immobilization and isomaltulose production

Isomaltulose (IM) is a non-cariogenic sugar and substitute for sucrose that has been widely used in candies and soft drinks. This sugar is obtained from sucrose through enzymatic conversion, catalyzed by microbial glucosyltransferases. In this study, alternative gums, namely: gum Arabic (GA), algaroba gum (AG), and cashew gum (CG) were combined with alginate (ALG) for the immobilization of Serratia plymuthica, with the aim of improving its capability for conversion of sucrose into IM. Prior to the immobilization, the gums were characterized using FTIR spectroscopy, TGA, and XRD analysis. Then, they were combined with ALG and used to immobilize a cell mass of S. plymuthica by ionic gelation. The morphology of the produced beads was visualized using SEM, and the sucrose into IM conversion using the beads was performed in batch and continuous processes. CG showed the highest thermal stability and crystallinity. The use of CG (2.0 %, w/v) combined with ALG (2.0 %, w/v) showed the highest value for isomaltulose (236.46 g/L) produced in the first batch, and high stability in the continuous conversion process; resulting in an IM production of 199.24 g/L at 72 h of reaction. In addition, this combination produced less porous beads, able to maintain the entrapped cells longer. In conclusion, the production of IM by Serratia plymuthica cells immobilized in a matrix composed of ALG and CG is recommended, due to its high conversion capacity and high stability.

Enhanced lead and copper removal in wastewater by adsorption onto magnesium oxide homogeneously embedded hierarchical porous biochar

Removing non-biodegradable Pb2+ and Cu2+ is the top priority in wastewater purification, while adsorption is a green technology to remove them. Herein, MgO-embedded granular hierarchical porous biochar (HP-MgO@BC) was fabricated by pyrolysis of porous Mg-infused chitosan beads. MgO nanoparticles were homogeneously embedded throughout the hierarchical porous biochar matrix in a high-density and accessible manner, thus providing a large number of easily accessible adsorption sites. Pb2+ and Cu2+ sorption capacities on HP-MgO@BC are 1044.8 and 811.2 mg/g at pH 5, respectively. It could effectively remove Pb2+ and Cu2+ across a broad pH range of 2–7, and show excellent adsorption efficiency in the presence of interfering cations. It also possessed excellent reusability. In the fixed-bed operation, 7880 BV (78.80 L) and 1610 BV (16.10 L) of synthetic Pb2+ and Cu2+ wastewater could be purified by HP-MgO@BC packed column, respectively. The adsorption mechanism involves mineral precipitation, ion exchange, and surface coordination.