Composite Hydrogel Beads Research Articles

Alginate/organo-selenium composite hydrogel beads: Dye adsorption and bacterial deactivation

Post-COVID-19, the risk and spread of germs, coupled with wastewater contamination, have become critical concerns. Wastewater contains waterborne bacteria and various contaminants like dye molecules, threatening water safety. Traditional adsorption methods address pollutant removal or pathogen inactivation separately, but a dual-action solution is increasingly essential. This study presents alginate/selenium composite hydrogel beads with the potential to simultaneously remove dyes and deactivating bacteria. Fabricated by dropping suspension droplets into a calcium ion bath, these beads were tested for dye adsorption and antibacterial efficacy. Beads with 50 wt% organo‑selenium demonstrated the highest methylene blue (MB) adsorption capacity and nearly 100 % deactivation efficiency against Pseudomonas aeruginosa, while those with 20 wt% showed no significant improvement. Mechanistic studies reveal that organo‑selenium induces stacking effects and reduces surface charges, enhancing MB adsorption and antibacterial performance. The alginate/organo‑selenium composite hydrogel beads offer a potential effective and sustainable solution for tackling the complex issue of wastewater pollutants.

Fabrication of pH-responsive whey protein/sodium alginate composite hydrogel beads for theaflavins

In this study, pH-responsive whey protein (WP)/sodium alginate (SA) composite hydrogel beads using the ionic gelation method were described and evaluated for their potential as delivery carriers for theaflavin (TF). Fourier transform infrared spectroscopy (FTIR) confirmed the interaction between WP and SA in the hydrogel beads is driven primarily by the strong intermolecular interactions, including hydrogen bonding and electrostatic attractions. The swelling ratio of the beads possesses good pH dependence and pH reversibility, effectively preventing the release of TF in the gastric environment. The encapsulation efficiency (EE) of TF in hydrogel beads ranged from 94.995 ± 0.03 to 95.709 ± 0.14, with a loading capacity (LC) of 27–34 mg/g. In in vitro digestion simulations, owing to the pH responsiveness, hydrogel beads released minimal TF throughout gastric digestion and were fully released in the intestine phase. Additionally, the release kinetics of TF from the beads were further examined in a simulated intestinal environment. These findings suggest that the hydrogel bead system is a promising carrier for encapsulating TF, offering a theoretical and experimental basis for its future application in the food industry.

Collagen-Based Hydrogel with Incorporated Nano-Hydroxyapatite for the Delivery of a Poorly Water-Soluble Drug

The goal of our research described here was to prepare a class of biocompatible composite hydrogel beads as a delivery system for the poorly soluble drug, cefixime. Hydrogel beads were synthesized using collagen (Col) and hydroxyapatite (HA) nanoparticles both extracted from fish wastes, and chitosan (Chi), for oral drug delivery. The in-vitro cytotoxicity of the Col showed good enough cell viability (95.51%) to be used as a potential candidate for biomedical applications, including tissue engineering and drug delivery. X-ray diffraction (XRD) patterns and Fourier transform infrared (FTIR) spectroscopy were used to determine the crystallinity and functional groups of the synthesized hydrogel beads. The fibrous structure of the beads was confirmed using scanning electron microscopy (SEM) images. The 1:1 ratio of Col:Chi without HA, resulted in a maximum swelling degree of 2010% and a drug release percentage of 93%. As the concentration of Col was increased, the swelling and cefixime release decreased. Adding HA NPs to the hydrogel structure led to an average 10% reduction in cefixime release compared to samples without HA. The release rate kinetics followed the first order and Korsmeyer-Peppas models, proving the diffusion was the controlling factor. The results showed that the mentioned hydrogel beads had a great potential delivery platform to achieve the controlled release of cefixime.

Novel porous hydrogel beads based on amidoxime modified polymer of intrinsic microporosity for efficient cationic dye removal

Due to the high surface area and facile functionalized or modified groups of polymers of intrinsic microporosity, and the hydrophilicity of sodium alginate (SA), a simple strategy was proposed for preparing porous composite hydrogel beads with excellent cationic dye adsorption capacity and selectivity. The porous composite hydrogel beads were prepared by introducing the amidoxime modified polymers of intrinsic microporosity (AOPIM-1) into SA polymer solution and then dropping the mixture into CaCl2 aqueous solution at low temperature for crosslinking. The prepared porous SA/AOPIM-1 hydrogel beads performed excellent adsorption capacity on Rhodamine B (RhB) from aqueous solution and the Langmuir model was suitable for describing the adsorption behavior of RhB on porous SA/AOPIM-1 hydrogel beads. It is surprising that the maximum theoretical adsorption capacity obtained by fitting the Langmuir model was up to 1648.3 mg·g−1. More importantly, porous SA/AOPIM-1 hydrogel beads showed outstanding selective adsorption capacity for cationic dyes in the mixed anionic and cationic dyes solution. Besides, the adsorption capacity of porous SA/AOPIM-1 hydrogel beads could maintain above 80 % of the initial adsorption capacity after 10 adsorption/desorption cycles. The above results indicate that porous SA/AOPIM-1 hydrogel beads can be used as a promising adsorbent with for effective removal of dyes from wastewater treatment.

Selective sensing of paraquat by simple off-the-shelf compounds: Applications using composite hydrogel beads and smartphone

The massive use of paraquat (PQ) in agricultural practices has posed serious threats to food safety and human health. Real-time monitoring of PQ remains an obstacle. Herein, a fluorometric as well as smartphone-based very cheap sensing assay is discussed for the detection of this non-selective contact herbicide PQ based on simple off-the-shelf commercially available dyes PTSA (1), HPTS (2) and Eosin Y (3) in pure aqueous media. Owing to their sensitivity towards PQ through electrostatic interactions, these dyes undergo a fluorescence quenching process. Dyes (2) and (3) show a rapid colorimetric change in the presence of PQ as shown by UV-Vis absorption spectral studies. 1 exhibits high sensitivity for PQ in comparison to 2 and 3 with the detection limit as low as 182 nM. All three probes exhibit high sensitivity, high selectivity for PQ over other analytes and excellent anti-interference properties. The Stern-Volmer plots and fluorescence lifetime studies confirm the static quenching process of the probes in the presence of PQ. Furthermore, sensor-coated paper-based test strips were successfully used for the ultrafast detection and quantification of PQ in spiked real water, fruit and vegetable samples. For the first time, silica-sodium alginate (SA) polymer hybrid hydrogel beads incorporated with probes 1, 2 and 3 were used for the detection and adsorption of PQ from water samples. For assessing the reliability of the proposed sensing system for the on-site detection of PQ, an easy-to-use portable test cassette kit integrated with a smartphone was used. The signal outputs were captured and analysed via RGB color value to use the probes for the practical application by using a smartphone as a portable analytical device for the rapid point-of-care monitoring of PQ.

Repurposing cottonseed meal as dye biosorbent

We successfully repurposed cottonseed meal (CSM) into alginate composite hydrogel beads for dye adsorption via a simple and efficient method. The beads entrapped CSM with up to 80 wt%. Effect of CSM on the physiochemical properties of composite hydrogel beads including swelling behaviors, chemical structures, thermal stability, and methylene blue (MB) adsorption capacity, was investigated. Compared to alginate gel beads, the alginate/CSM composite system exhibited a drastic increase in thermal stability and a synergistic effect in dye adsorption capacity, where the dye adsorption capacity was well maintained, despite the inherently lower capacity when used alone. Such synergistic effect appeared to be linked to the reduced size of CSM particles within the gel network, while dye adsorption mechanism was attributed to the electrostatic attraction and hydrogen bonding between the biosorbents and dye. Our current study offers a feasible and cost-effective approach for upcycling CSM as biosorbent for dye decontamination.

Efficiently adsorptive removal of chloroquine phosphate by poly(sodium p-styrenesulfonate)/tannic acid/sodium alginate ternary composite hydrogel bead

Efficiently adsorptive removal of chloroquine phosphate by poly(sodium p-styrenesulfonate)/tannic acid/sodium alginate ternary composite hydrogel bead

Covalent organic framework@cellulose nanofibrils@carboxymethyl cellulose composite hydrogel beads for the removal of nickel ions from aqueous solutions

A novel adsorbent, covalent organic framework (COF)@cellulose nanofibrils (CNF) @carboxymethyl cellulose (CMC) composite hydrogel bead (CCCHB), was prepared for Ni2+ removal from aqueous solutions. The imine COF provides the main active sites for adsorption. CNF is used as the carrier for grafting COF to improve the dispersion of COF and the reinforcing material. CMC is used as the hydrogel matrix to facilitate easy recycling. The equilibrium adsorption capacity (qe) of the CCCHB is vastly influenced by the mass ratio of COF@CNF/CMC. The optimized mass ratio of COF@CNF/CMC is 0.050/1 (g/g). The maximum adsorption is reached at pH=6. The qe of Ni2+ increases with a rise in initial concentration of the solution. Based on Langmuir isotherms, the maximum adsorption capacity of CCCHB is 289.50 mg/g. The adsorption of Ni2+ complies with the pseudo-second-order kinetic model. The CCCHBs still maintain preferable adsorption properties after the seventh cycle of adsorption–desorption. The Ni2+adsorption of the CCCHB is mainly attributed to the chelating effect and electrostatic interaction.

Intestinal-specific oral delivery of lactoferrin with alginate-based composite and hybrid CaCO3-hydrogel beads

Sodium alginate hydrogel beads and sodium alginate/gellan gum composite hydrogel beads crosslinked by calcium chloride were prepared with different alginate concentrations (3–20 mg·mL−1). Additionally, a simple method for growing CaCO3in situ on the hydrogel to create novel inorganic-organic hybrid hydrogel beads was presented. FT-IR analysis revealed the involvement of hydrogen bonding and electrostatic interactions in bead formation. Swelling behavior in acidic conditions showed a maximum of 13 g/g for composite hydrogels and CaCO3-incorporated hybrid hydrogels. Lactoferrin encapsulation efficiency within these hydrogels ranged from 44.9 to 56.6%. In vitro release experiments demonstrated that these hydrogel beads withstand harsh gastric environments with <16% cumulative release of lactoferrin, achieving controlled release in intestinal surroundings. While composite sodium alginate/gellan gum beads exhibited slower gastrointestinal lactoferrin digestion, facile synthesis and pH responsiveness of CaCO3-incorporated hybrid hydrogel also provide new possibilities for future studies to construct a novel inorganic-organic synergetic system for intestinal-specific oral delivery.

Investigation of swelling behaviour monolayer and double Layer polysaccharide based composite hydrogels

ABSTRACT In this study, monolayer and double layer (core-shell) composite hydrogel beads with and without hydroxyapatite which have potential applications in drug delivery systems were synthesized, and their swelling behaviours were investigated in different pH mediums. The composite hydrogel beads was prepared by crosslinking sodium alginate and kappa-carrageenan (by using Ca+2 and K+1). Core-shell hydrogel beads were formed by coating monolayer composite hydrogel beads with the mixture of sodium alginate and kappa-carrageenan. The structure of hydrogel beads was characterized by Fourier Transform Infrared Spectrophotometer, Scanning Electron Microscopy and Differential Scanning Calorimetry. The effects of the composite hydrogel beads combination and the concentration of crosslinker on swelling behaviours were investigated. Swelling kinetics data were tested using pseudo-second-order model, and the pseudo-second-order model is estimated as a convenient model to represent the swelling kinetic. The results indicated that swelling behaviours of hydrogel beads changed with composite hydrogel beads combination and concentration of crosslinker.

Agarose‐sodium alginate hydrogel beads enhanced with zeolitic imidazolate frameworks/multiwalled carbon nanotubes nanoparticles for efficient adsorption and selective separation of methylene blue

AbstractThe urgent problem to solve is how to design a kind of green and porous adsorbent that can effectively remove dye pollutants in the field of the sewage treatment. The objectives of this investigation are to incorporate zeolitic imidazolate frameworks‐8 (ZIF‐8) particles in situ onto the surface of multiwalled carbon tubes (MWCNTs) and integrate them into an agarose‐sodium alginate (ASA) double network hydrogel. The resulting composite hydrogel beads, denoted as MWCNTs/ZIF‐8/ASA (MZASA), are synthesized using calcium ion crosslinking. The addition of agarose is employed to create a dual‐crosslinked hydrogel, thereby enhancing the mechanical properties of the ASA hydrogel. By incorporating MWCNTs/ZIF‐8 nanoparticles, the surface area of the MZASA hydrogel is augmented, leading to an enhancement in dye adsorption capacity. In batch sorption mode, the maximum absorbency of the resulting hydrogel beads for methylene blue (MB) is 493.799 mg/g, which was a third greater than that of pure SA beads. Absorption of MB obeys the pseudo‐second‐order kinetic model and Langmuir isotherm model, suggesting monolayer chemisorption adsorption. Analysis of the thermodynamics proves that the entire adsorption process is exothermic and spontaneous. Moreover, the MZASA hydrogel beads show high selectivity for cationic dyes in the mixed dye test. Hence, the synthesized MZASA hydrogel beads serve as a highly effective, innovative, and reusable adsorbent for eliminating cationic dyes from water‐based solutions.

Fabrication and characterization of magneto-responsive polyvinyl alcohol–alginate composite hydrogel beads for the removal of cationic dyes from aqueous solutions

In this study, magneto-responsive polyvinyl alcohol–alginate hydrogel beads are successfully fabricated using the electrospraying technique and applied as efficient adsorbents for the removal of cationic dyes, particularly malachite green (MG) and methylene blue (MeB), from water. The successful synthesis of the beads is confirmed using optical microscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy. Additionally, batch adsorption studies are performed to evaluate the adsorption capacity of the hydrogel beads under varying concentrations, pH solution, and contact time. Results revealed that the beads exhibited excellent sorption capacities of 270.03 and 285.66 mg g−1 toward MG and MeB, respectively, indicating their potential as efficient adsorbents for cationic dye removal. The adsorption mechanism of the beads was further analyzed using kinetic and isotherm models, where the results revealed that the pseudo-second order kinetic model and Langmuir isotherm model exhibited the best fits with the experimental data. The incorporated magnetic nanoparticles enabled the easy separation and reuse of the hydrogel beads sample, as it maintained more than 75% of its efficiency even after five consecutive cycles. This study presents an innovative and sustainable solution for wastewater treatment, demonstrating the use of magneto-responsive hydrogel beads as effective and reusable adsorbents for cationic dye removal.

Enhanced viability of probiotics in composite hydrogel beads

Composite hydrogel is common way to protect probiotics from harsh environment. The study designed and optimized double-saccharide composite hydrogel beads for the encapsulation of Companilactobacillus crustorum MN047 (C. crustorum MN047) by adjusting the combination ratios of low methoxyl pectin (LMP) and sodium alginate (SAG) and the concentrations of calcium chloride (CaCl2). Encapsulation efficiency of hydrogel beads ranged from 87.69% to 99.98%. Hydrogel beads significantly increased the viability of C. crustorum MN047 in the simulated gastrointestinal (the number of viable probiotics was more than 7 log CFU/g at simulated SIF for 4 h) and storage environments (the number of viable probiotics was more than 7 log CFU/g at 25 °C at day30). Rheological tests proved pectin-based hydrogel possessed stronger crosslinking degree than alginate-based hydrogel. FT-IR and SEM indicated C. crustorum MN047 was encapsulated successfully, and polyelectrolyte polymers along with Ca-crosslinking play an important role in the formation mechanism. These results are attributed to the design of probiotic encapsulation systems and the promotion of the exploitation of probiotic functional products.

Eco-friendly Biodegradation of Hydrocarbons Compounds from Crude Oily Wastewater Using PVA/Alginate/Clay Composite Hydrogels

Immobilized microorganisms especially bacteria are most used rather than free cells to be protected from the environmental conditions when being used for the bioremediation of environmental pollutants. Herein, two marine’s bacterial isolates were tested for their ability to decompose crude oil. The optimum conditions for effective bacterial degradation e.g., pH, temperature, and inoculum size were investigated. PVA-alginate-clay composite hydrogel beads with different types of incorporated mineral clays were prepared and tested as bacterial carrier for potential bioremediation. Synthesized composite hydrogels were physico-chemically characterized by FTIR, SEM, and thermal analyses. Results showed that, embedded degrading bacteria in PVA-alginate beads recorded degradation rates as 74 and 66.6% for both tested bacterial isolates (S and R) compared to 61.2 and 53% degradation rates by free cells, respectively. Where, attapulgite clay-containing beads recorded maximum degradation% as 78.8 and 75% for both bacterial isolates, when added to immobilization matrices and these percentages could be enhanced under optimal conditions. The 16S rRNA gene of the two marine oils degrading bacterial isolates were amplified and sequenced, where both isolates were identified as Pseudomonas stutzeri and Rhodococcus qingshengii with submitted accession numbers of ON908963 and ON908962, respectively. These results are referring to the ability of using both tested isolates for crude oil bioremediation process and embedded them into PVA-alginate-clay beads as hydrogel carrier under the optimum conditions.

Competitive recovery of copper ions using ethyl acetoacetate modified chitosan/organo-functionalized alginate hydrogel beads: kinetics and isothermal sorption studies

Surface functionalization of chitosan using some chelating ligands not only improves sorption capacity but also induces selectivity into the biopolymer. The current study is based on the facile synthesis of ethyl acetoacetate modified chitosan and surface-functionalized alginate composite beads (EAA-MCSA). Chemical modification of sodium alginate was carried out to graft amino thiocarbamate moiety (-OCSNHNH2) to entrench selectivity and specificity across the linear chains of preliminary polysaccharide. Biosorbent (EAA-MCSA) was thoroughly characterized by FT-IR and SEM analysis and employed in the form of composite hydrogel beads for competitive Cu(II) recovery. Newly grafted aminothiocarbamate (-OCSNHNH2) and 1,3-dicarbonyl moieties (-COCH2CO-) are supposed to act as potential chelating sites for enhanced Cu(II) sorption. Kinetic data could be well depicted using pseudo-second order rate law (R2 = 0.99, qexp≈qe,th = 85.25 mg/g, k2 = 0.45–1.17 ×10−2 g/mg.min−1) and sorption data was found in close agreement with Langmuir adsorption isotherm (R2 = 0.99, qm= 390.21 mg/g at 298 K and pH = 6.0, KL= 0.44–0.49 ×10−2 L/mg). The ΔG° values (−20.75, −21.10, −21.30 and −21.50 kJ/mol) and positive ΔH° (−7.63 kJ/mol) designated the sorption process as spontaneous and exothermic, respectively. Hence, EAA-MCSA could be a better sorbent for adsorptive remediation of Cu(II) from dilute effluents.

Preparation of Chitosan-Diatomite/Calcium Alginate Composite Hydrogel Beads for the Adsorption of Congo Red Dye

In this paper, novel eco-friendly cross-linked chitosan-diatomite/calcium alginate (CS-DE@CA) composite hydrogel beads were successfully prepared for water purification. The obtained sorbents were characterized and studied by using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA), which confirmed the successful modification and encapsulation of diatomite into hydrogel beads. The adsorption performance of composite beads for Congo red in an aqueous solution was studied by ultraviolet-visible spectrophotometry. In particular, the CS-DE@CA exhibited higher removal efficiencies (~89.9%) than the removal efficiencies (~83.6%) of the DE@CA (in the temperature = 20 °C, 100 mL, 50 mg/L, and pH = 7). It was also found that adsorption capacity of Congo red increased from 23.28 mg/g to 38.84 mg/g when the starting concentration increased from 25 mg/L to 75 mg/L. The adsorption process was dominated by chemisorption, and its maximum adsorption capacity for Congo red was calculated to be 48.42 mg/g by Langmuir model. Additionally, the as-prepared sorbent maintained an exceptional adsorption capacity after four adsorption–desorption cycles. Overall, this study also provides new guidance and avenues for further fabrication and development of eco-friendly purifier for the removal of Congo red in contaminated water.

Preparation of CO2/N2-switchable hydrogel beads and adsorption, desorption, regeneration for Cu(Ⅱ)

CO2/N2-stimulated compounds have been widely used in separation field. However, their application as adsorbent for heavy metal ions removal remains a huge challenge. In this work, chitosan was incorporated into alginate matrix to form composite hydrogel beads with CO2/N2-switchable responsibility. A systematic adsorption test for Cu2+ was conducted and the prepared CTS-SA@calcium hydrogel beads presented an adsorption capacity of 125 mg·g−1. Moreover, these hydrogel beads can be desorbed effectively by bubbling CO2 and then be regenerated effectively by bubbling N2. The desorption is attributed to the amion-rich chitosan, which could be reacted with carbonic acid in water, while the regeneration is attributed to the transition of amino groups from protonated/cationic form to non-protonated/neutral form. This switched adsorption - desorption - regeneration cycle can be repeated several times. Compared with the traditional desorption using strong acids, this CO2/N2-switchable desorption - regeneration strategy holds a great potential for adsorbent regeneration and practical wastewater treatment.

Sodium-alginate-laden MXene and MOF systems and their composite hydrogel beads for batch and fixed-bed adsorption of naproxen with electrochemical regeneration

Sodium alginate (SA)-laden two-dimensional (2D) Ti3C2Tx MXene (MX) and MIL-101(Fe) (a type of metal–organic framework (MOF)) composites were prepared and used for the removal of naproxen (NPX), following the adsorption and electrochemical regeneration processes. The fixed-bed adsorption column studies were also conducted to study the process of removal of NPX by hydrogels. The number of interactions via which the MX-embedded SA (MX@SA) could adsorb NPX was higher than the number of pathways associated with NPX adsorption on the MIL-101(Fe)-embedded SA (MIL-101(Fe)@SA), and the MX and MIL-101(Fe) composite embedded SA (MX/MIL-101(Fe)@SA). The optimum parameters for the electrochemical regeneration process were determined: charge passed and current density values were 169.3 C g−1 and 10 mA cm−2, respectively, for MX@SA, and the charge passed and current density values were 16.7 C g−1 and 5 mA cm−2, respectively, for both MIL-101(Fe)@SA and MX/MIL-101(Fe)@SA. These parameters enabled excellent regeneration, consistent over multiple adsorption and electrochemical regeneration cycles. The mechanism for the regeneration of the materials was proposed that the regeneration of MX@SA and MIL-101(Fe)@SA involved the indirect electrooxidation process in the presence of OH radicals, and the regeneration of MX/MIL-101(Fe)@SA involved the indirect oxidation process in the presence of active chlorine species.

Fabrication and Characterization of Magnetic Cellulose-Chitosan-Alginate Composite Hydrogel Bead Bio-Sorbent.

The implementation of inorganic adsorbents for the removal of heavy metals from industrial effluents generates secondary waste. Therefore, scientists and environmentalists are looking for environmentally friendly adsorbents isolated from biobased materials for the efficient removal of heavy metals from industrial effluents. This study aimed to fabricate and characterize an environmentally friendly composite bio-sorbent as an initiative toward greener environmental remediation technology. The properties of cellulose, chitosan, magnetite, and alginate were exploited to fabricate a composite hydrogel bead. The cross linking and encapsulation of cellulose, chitosan, alginate, and magnetite in hydrogel beads were successfully conducted through a facile method without any chemicals used during the synthesis. Energy-dispersive X-ray analysis verified the presence of element signals of N, Ca, and Fe on the surface of the composite bio-sorbents. The appearance and peak's shifting at 3330-3060 cm-1 in the Fourier transform infrared spectroscopy analysis of the composite cellulose-magnetite-alginate, chitosan-magnetite-alginate, and cellulose-chitosan-magnetite-alginate suggested that there are overlaps of O-H and N-H and weak interaction of hydrogen bonding with the Fe3O4 particles. Material degradation, % mass loss, and thermal stability of the material and synthesized composite hydrogel beads were determined through thermogravimetric analysis. The onset temperature of the composite cellulose-magnetite-alginate, chitosan-magnetite-alginate, and cellulose-chitosan-magnetite-alginate hydrogel beads were observed to be lower compared to raw-material cellulose and chitosan, which could be due to the formation of weak hydrogen bonding resulting from the addition of magnetite Fe3O4. The higher mass residual of cellulose-magnetite-alginate (33.46%), chitosan-magnetite-alginate (37.09%), and cellulose-chitosan-magnetite-alginate (34.40%) compared to cellulose (10.94%) and chitosan (30.82%) after degradation at a temperature of 700 °C shows that the synthesized composite hydrogel beads possess better thermal stability, owing to the addition of magnetite and the encapsulation in the alginate hydrogel beads.

A composite zinc oxide and magnetic molecularly imprinted polymer hydrogel adsorbent for the extraction of sulfonamides in milk

A composite adsorbent hydrogel bead was developed by coating zinc oxide and magnetite nanoparticles on a molecularly imprinted polymer embedded in alginate (ZnO/Fe3O4@SiO2-NH2/MIP/alginate). The adsorbent was fabricated and applied to extract and enrich trace sulfonamides in milk for determination by high-performance liquid chromatography (HPLC). Zinc oxide improved the adsorption efficiency of sulfonamides via hydrogen bonding. The magnetite nanoparticles enabled the simple and rapid separation of the adsorbent from the sample solution after extraction and desorption. The molecularly imprinted polymer increased selectivity toward the target analytes. Under optimum conditions, the developed method provided linearity from 0.20 to 1000 μg L−1 for sulfamethazine (SMT) and from 0.10 to 1000 μg L−1 for sulfadimethoxine (SDM) with R2 greater than 0.995. The limits of detection (LODs) were 0.06 and 0.03 μg L−1 for SMT and SDM respectively. The developed method was utilized to extract the two sulfonamides from milk samples, and a trace SDM concentration of 0.65 μg L−1 was found in one sample. Relative recoveries were achieved in the range of 87.0 to 98.5% with RSDs lower than 6%. The advantages of the proposed adsorbent are simplicity, good selectivity, high extraction efficiency and accuracy.