Acid Eluent Research Articles

Preparation of micron-sized benzamidine-modified magnetic agarose beads for trypsin purification from fish viscera

The effective method for trypsin purification should be established because trypsin has important economic value. In this work, a novel and simple strategy was proposed for fabricating micron-sized magnetic Fe3O4@agarose-benzamidine beads (MABB) with benzamidine as a ligand, which can efficiently and selectively capture trypsin. The micro-sized MABB, with clear spherical core-shell structure and average particle size of 6.6 μm, showed excellent suspension ability and magnetic responsiveness in aqueous solution. The adsorption capacity and selectivity of MABB towards target trypsin were significantly better than those of non-target lysozyme. According to the Langmuir equation, the maximum adsorption capacity of MABB for trypsin was 1946 mg g−1 at 25 °C, and the adsorption should be a physical sorption process. Furthermore, the initial adsorption rate and half equilibrium time of MABB toward trypsin were 787.4 mg g−1 min−1 and 0.71 min, respectively. To prove the practicability, MABB-based magnetic solid-phase extraction (MSPE) was proposed, and the related parameters were optimized in detail to improve the purification efficiency. With Tris-HCl buffer (50 mM, 10 mM CaCl2, pH 8.0) as extraction buffer, Tris-HCl buffer (50 mM, 100 mM CaCl2, pH 8.0) as rinsing buffer, acidic eluent (0.01 M HCl, 0.5 M NaCl, pH 2.0) as eluent buffer and alkaline buffer (1 M Tris-HCl buffer, pH 10.0) as neutralization solution, the MABB-based MSPE was successfully used for trypsin purification from the viscera of grass carp (Ctenopharyngodon idella). The molecular weight of purified trypsin was determined as approximate 23 kDa through sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The purified trypsin was highly active from 30 °C to 60 °C, with an optimum temperature of 50 °C, and was tolerant to pH variation, exhibiting 85 % of maximum enzyme activity from pH 7.0 to 10.0. The results demonstrated that the proposed MABB-based MSPE could effectively purify trypsin and ensure the biological activity of purified trypsin. Therefore, we believe that the novel MABB could be applicable for efficient purification of trypsin from complex biological systems.

Utilization of Matrix Effect for Enhancing Resolution in Cation Exchange Chromatography.

In ion chromatography studies, the matrix effect of other inorganic ions present in the sample is a well-known phenomenon. In this work, the behavior of inorganic and organic ions was studied in a system overloaded with ammonium ions. The ammonium ions came from a solution of ammonium hydroxide in various concentrations (0.25-1.25%). In this system, which was significantly overloaded with ammonium ions, the behavior of three ions were tested (lithium, tris, and sodium cations). The measurements were performed at different eluent concentrations (6-17 mM), chromatographic column temperatures (25-40 °C), and injected volumes (15-40 µL). The retention times of sodium and lithium ions increased with increasing amounts of injected ammonium, while tris remained essentially unchanged, indicating that the resolution of these ions can be influenced by varying the concentration of the matrix. The results suggested that the observed effect was due to a combination of the pH change caused by the injected matrix, the dissociation of tris ions, the dissociation of the carbocylic ion-exchange groups of stationary phase, the change in buffer capacity, and the amount of ammonium ion introduced. It has been shown that in a well-designed experiment, the addition of ammonium hydroxide to the sample at concentrations greater than 1% can improve the efficiency of organic and inorganic cation separation. It was found that 8 mM methanesulfonic acid eluent, 30 °C, 1% ammonium hydroxide matrix concentration, and 25 µL injection were optimal for the baseline separation of tris and sodium ions on the high-capacity Dionex CS16 column. These ions could not be separated on this column without the presence of the ammonium matrix.

Improving the efficiency of acidic eluents for elution of Scandium from Lewatit® VP OC 1026 and TP 272 solvent impregnated ion exchange resins

Scandium is a strategic element with exceptional applications however, its widespread application has been limited mainly due to its high price which itself originates from lack of enriched primary reserves. Mineralized waste materials and mine tailings collected from various mining activities often contain low amounts of Sc and rare earth elements (REE), along with much higher levels of contaminants such as Si, Fe and Al. Ion exchange resins, especially phosphorus containing solvent impregnated ones, show extremely high selectivity for quantitative adsorption of Sc from pregnant leach solutions. However, efficient and economical elution of Sc from these types of resins is still a challenge. In this study, a series of water miscible organic solvents including methanol, ethanol, 1-propanol, 2-propanol and acetone are explored with sulfuric acid in elution of Sc at room temperature (25 °C). With the proposed binary solvent system in this study, 98% of the adsorbed Sc was eluted from VP OC 1026 (impregnated with D2EHPA) with 4 M H2SO4 in 50 vol.% 1-propanol while negligible amount of Sc could be recovered with 2 M H2SO4 even at high temperatures. Also, exceeding 97% of the loaded Sc on TP 272 (impregnated with Cyanex 272) could be successfully eluted with 6 M H2SO4 containing 50 vol.% 2-Propanol. Nevertheless, the elution efficiency of Sc from TP 272 was notably constrained, falling below 20 %, when 2 M H2SO4 was employed as the eluent. The added organic solvents also significantly increased the performance of H2SO4 in elution of Sc from the resins in columns. The addition of just 10 vol.% 2-propanol to 2 M H2SO4 led to significant increase in the elution of Sc from TP 272. The maximum concentration of Sc in the eluted fractions increased by over threefold, going from 167.0 mg/L to 532.6 mg/L, when compared to using 2 M H2SO4 under similar elution conditions.

Enhanced removal of lead and zinc by a 3D aluminium sulphate-functionalised graphene aerogel as an effective adsorption system

The discharge of heavy metals into the environment has adversely affected the aquatic ecosystem due to their toxic and non-biodegradable nature. In this research, a three-dimensional graphene oxide/carboxymethylcellulose/aluminium sulphate (GOCAS) aerogel was synthesised and evaluated as a novel means for lead and zinc removal. The GOCAS aerogel was prepared via ice-templating of graphene oxide with carboxymethylcellulose and aluminium sulphate as the crosslinking and functionalisation additives. Characterisation of the aerogel by various analytical techniques confirmed the successful integration of the chemical additives. The hydroxyl and sulphate groups in the aerogel were found to participate in the adsorption of both metals. The equilibrium of lead adsorption was found to correlate well to the Freundlich isotherm, while zinc adsorption fitted closely the Langmuir isotherm. The kinetic adsorption behaviour of both metals was best described as pseudo-second-order. The interactive influences of concentration, temperature, contact time and adsorbent dose on the metal removal were explored by a central composite design, and the optimum adsorption capacity for lead was determined to be 138.7 mg/g at a GOCAS dose of 20 mg, initial concentration of 100 mg/L, temperature of 50 °C and contact time of 45 min. The optimum adsorption capacity for zinc was 52.69 mg/g at 30 mg, 65 mg/L, 45 °C and 40 min. Furthermore, regeneration studies with hydrochloric acid eluant were successfully conducted for up to four adsorption-desorption cycles. Overall, this work demonstrates that GOCAS aerogel is a viable nanosorbent for the adsorption of lead and zinc from water systems.

Development of a method for the simultaneous determination of ionic nutrients in hydroponic solutions using cation-/anion-exchange chromatography with a neutral eluent.

Nutrient availability in hydroponic solutions must be accurately monitored to maintain crop productivity; however, few cost-effective, accurate, real-time, and long-term monitoring technologies have been developed. In this study, we describe the development and application of cation-/anion-exchange chromatography with a neutral eluent (20-mmol/L sodium formate, pH 7.87) for the simultaneous separation (within 50min) of ionic nutrients, including K+, NH4+, NO2-, NO3-, and phosphate ion, in a hydroponic fertilizer solution. Using the neutral eluent avoided degradation of the separation column during precipitation of metal ion species, such as hydroxides, with an alkaline eluent and oxidation of NO2- to NO3- with an acidic eluent. The suitability of the current method for monitoring ionic components in a hydroponic fertilizer solution was confirmed. Based on our data, we propose a controlled fertilizer strategy to optimize fertilizer consumption and reduce the chemical load of drained fertilizer solutions.

Influence of terephthalate anion in ZnAl layered double hydroxide on lead ion removal: Adsorption, kinetics, thermodynamics and mechanism

In this work, layered double hydroxides (LDHs) intercalated with carbonate (ZnAl-CO3) and terephthalate (ZnAl-TA) anions were synthesized for the removal of lead (Pb2+) ions from aqueous solutions. ZnAl-TA showed better Pb2+ removal performance than ZnAl-CO3. In the kinetic study, the Elovich model obtained the best fit; the Weber-Morris model showed that intraparticle diffusion is not a limiting step in the process. The Sips model fitted better to the adsorption isotherms, with a maximum adsorption capacity of 124 mg.g−1. The thermodynamic study showed that the process is spontaneous and endothermic. In the regeneration of ZnAl-TA, the use of NaCl as a desorption eluent showed less Zn2+ leaching and greater desorption efficiency compared to acid eluents. The adsorption capacity of Pb2+ in the presence of other ions followed the order Ni2+ > Ca2+ > Cd2+ > Mg2+ > Cu2+. The ZnAl-TA adsorbent reached 88% of its initial efficiency after 3 cycles with high stability. From post-adsorption XRD, FTIR, and XPS analyses, Pb2+ was removed predominantly by chelation, surface complexation, and precipitation. In general, the ZnAl-TA adsorbent proved to be an efficient sorbent material for Pb2+ removal from aqueous effluent.

Highly efficient entrapping and recovery of gadolinium and samarium ions by nano cerium orthovanadate from acidic solutions

Cerium orthovanadate nano-rods were prepared using template free-low temperature procedure and tested for their potential use in the entrapping of lanthanide ions. The adopted preparation procedure yielded in the production of uniform nano-rods with respectively smaller dimensions compared to other methods that utilize higher crystallization temperature and/or template. The material was fully characterized using HRTEM/SAED, SEM, FTIR, XRD to determine its crystalline structure and morphological characteristics. The material has buffer ability in acidic solutions and notable stability in different alkaline and acidic eluents. Gd and Sm ions entrapping performances are optimum in the acidic solutions in pH range (2.5 ≤ pH ≤ 6) with suitable control to avoid negative perturbation in the solution pH. The results of the direct sensitivity analysis for operating the process at room temperature indicate that Sm entrapping is more sensitive than Gd ions. The entrapping is controlled by multiple mechanisms that involve sorption on the external surface and diffusion into the interior pore structure of the material. The material has higher affinity toward Gd ions entrapping and recovery, and its monolayer capacity is higher than that reported in the literature for actinides removal. The material could be efficiently regenerated and reused for 5 cycles without considerable loss in the efficiency. This novel material and its efficient entrapping and recovery potential for Gd and Sm ions provides innovative application of orthovanadate materials to enhance the extraction of lanthanides from acidic solutions and improve the control on the release of these emerging contaminant into the ecosystem.

Multi-Functional Separation Mode-Ion Chromatography Using L-Pyroglutamic Acid Eluent for Simultaneous Determination of Sugars, Organic Acids, and Ethanol during Multiple Parallel Fermentation of Rice Wine

An effective evaluation method for understanding fermentation is required to support the implementation of newly developed yeast strains in brewing. Our group developed a multi-functional separation mode-ion chromatography (MFS-IC) with conductivity and refractive index detectors to separate key species (glucose, ethanol, and organic acids: pyruvate, citrate, L-malate, and succinate) with ethyl α-D-glucoside and glycerol to understand the fermentation behavior in brewing. Optimal chromatographic resolutions for determining eight different key species in rice wine by the MFS-IC were obtained in 45 min on low-molecular size-exclusion chromatographic separation columns modified with a strong cation-exchanger as the stationary phase with an eluent of L-pyroglutamic acid. Understanding the behavior of analytes in rice wine samples during rice wine fermentation enables the monitoring of the progress of saccharification, glycolysis, ethanol fermentation, and the tricarboxylic acid (TCA) cycle. These results are expected to contribute to understanding fermentation characteristics and implementing newly developed yeast strains in the fermentation field.

A reagent-free acid-base titration method via an electrodialytic titrant generator

We describe a reagent-free acid-base titration method, in which only water is added and the titrant is online electrodialytically produced. Electrodialytic eluent generator, a well-established technique in ion chromatography to produce high purity base or acid eluent through precise control of an electric current, has been for the first time used for titration, termed as electrodialytic titrant generator (ETG). Three kinds of titrants produced by ETG have been demonstrated, including potassium hydroxide, methanesulfuric acid and sulfuric acid. A series of titrants with different concentration up to at least 140 mM (e.g. KOH) could be accurately and reproducibly obtained by manipulating current and the KOH titrant showed extremely high purity. The titration results achieved by ETG were in a good agreement with those obtained by the regular way and their ratio was in the range of 0.9918 and 1.0034. Good accuracy and precision were achieved for ETG titration, as indicated by 2.2% of relative error and 0.17% of relative standard error. Its utility was demonstrated to measure pKa-differentiated capacity of anion exchange resins.

Study on Adsorption Performance of Benzoic Acid in Cyclocarya paliurus Extract by Ethyl Cellulose Microspheres

Polymer microspheres with inter-connecting pores are widely used as microsphere materials. In the study, the ethyl cellulose microspheres (ECM) were prepared by using the solvent-evaporation method. Based on that, a method for the separation and purification of benzoic acid from crude extract of Cyclocarya paliurus was established by the ECM and high performance liquid chromatography (HPLC). The ECM after the sorption equilibrium was desorbed by using 40% methanol as the analytical solvent. The content of benzoic acid in eluent is up to 0.0216 mg/mL, and the benzoic acid can be obtained with a high purity of 82.22%. Furthermore, the adsorption-desorption behavior of benzoic acid onto ECM was investigated. The results of adsorption kinetics of benzoic acid showed that the adsorption followed the pseudo-first-order kinetic model. The ECM was characterized by using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and X-ray diffraction (XRD). The results showed that the ECM has a high adsorption property due to its more porous structure, phenolic hydroxyl group, and other oxygen-containing functional groups. This method and the ECM can be used stably, continuously, and efficiently to purify the benzoic acid from the methanol extract of C. paliurus on a large scale.

Fixed-bed column dynamics of ultrasound and Na-functionalized diatomite to remove phosphate from water.

A continuous fixed-bed column study was used to evaluate phosphate adsorption performance of U-D-Na which was functionalized by the cheap NaCl reagent after simple ultrasonic purification of diatomite. In this work, various effect factors, including flow rate, initial phosphate concentration, and the bed height, on breakthrough performance of fixed column were investigated. Experimental results demonstrated that the breakthrough time declined with the increase of inlet phosphate concentration and feed rate, whereas the increase of bed height turned out to significantly extend the breakthrough time. The dynamic adsorption process could be well fitted by the Thomas model, with a correlation coefficient R2 > 0.9000 under main operating conditions. A thrice loop of effective regeneration was achieved with 0.1 M hydrochloric acid eluent and deionized water. The maximum removal rate for phosphate was more than 95% in the column adsorption process. The results proved that U-D-Na could be used as a better alternative phosphate adsorbent for wastewater in a continuous column sorption process.

A tailored magnetic composite synthesized by graphene oxide, chitosan and aminopolycarboxylic acid for diminishing dye contaminant

This research study aims to remove methyl violet from aqueous solutions with a novel composite. The composite was synthesized by magnetite nanoparticles decorated with amino-silane, graphene oxide, and grafted chitosan-diethylenetriaminepentaacetic acid. The adsorbent was characterized by FT-IR, XRD, FESEM, TEM, EDX, elemental mapping, TGA, VSM, and BET. The Central Composite Design was used for planning the adsorption experiments. The maximum dye removal was equal to 94.87% for an initial dye concentration of 10.0 mg L−1. The coulombic attraction, H-bonding, and pi stacking interactions were proposed as the key factors for dye removal. The initial pH and temperature were fixed at 9.8 and 52.3 °C and the adsorbent dosage was 2.0 g L−1 in the kinetics and equilibrium studies. The adsorption process was almost completed within five min. The modified pseudo-n-order model was the best equation to fit the kinetics data. It was demonstrated that film diffusion was the rate-limiting step at the initial stages of dye removal after which the dye adsorption was the rate-determining step. The equilibrium data was fitted by modified Langmuir–Freundlich isotherm and the maximum equilibrium adsorption was 243.8 mg g−1. Besides, the composite recovery was done by a low amount of acidic eluent. The adsorption efficiency did not change even after five desorption-adsorption cycles.

Miniaturized Low-Pressure Ion-Exchange Module and Its Application to an Acidic Eluent Generator for Open Tubular Ion Chromatography

Miniaturized Low-Pressure Ion-Exchange Module and Its Application to an Acidic Eluent Generator for Open Tubular Ion Chromatography

A Molecularly Imprinted Electrochemical Luminescence Sensor for Detection of Gibberellin Based on Energy Transfer

A molecularly imprinted sensor was fabricated, and a method of enhancing the electrochemiluminescence (ECL) signal of Ru(bpy) 3 Cl 2 using resonance energy transfer (RET) method was established for ultra-sensitive determination of gibberellin (GA3). Au-doped g-C 3 N 4 (g-C 3 N 4 /Au) material was prepared on the surface of glassy carbon electrode (GCE), and then o -phenylenediamine was electropolymerized to achieve a molecularly imprinted polymer (MIP) film. Elution was performed with a methanol-acetic acid eluent to obtain a cavity that specifically recognized GA3. In the experiment, Ru(bpy) 3 2+ was used as the probe and g-C 3 N 4 /Au was used as the energy donor. The RET between Ru(bpy) 3 2+ and g-C 3 N 4 /Au was used to enhance the ECL intensity of Ru(bpy) 3 2+ . In addition, ECL-RET was combined with molecular imprinting technology to improve the selectivity of the sensor. With the increase of the concentration of GA3 in the sample, the molecularly imprinted cavities recombined with GA3 which made the ECL intensity gradually decrease. Under the optimized conditions, it was found that the there was a linear relationship between ECL intensities and the GA3 concentrations in the range of 4.00 × 10 −14 − 7.00 × 10 −11 mol/L, and the detection limit was 1.64 × 10 –14 mol/L (DL = 3 S / K ). The sensor was successfully applied to the detection of GA3 in beer, and the recoveries were 95.7%–103.7%. A molecularly imprinted sensor was fabricated for gibberellin (GA3) determination by electrochemiluminescence resonance energy transfer (ECL-RET) method. g-C 3 N 4 /Au was modified on a glassy carbon electrode, and then a MIP film was synthesized on its surface. The ECL signal of Ru(bpy) 3 Cl 2 probe was enhanced significantly by ECL-RET system, by which the g-C 3 N 4 /Au donor transferred energy to the Ru(bpy) 3 Cl 2 acceptor. High sensitivity was achieved for GA3 detection with a detection limit of 1.64 × 10 -14 mol/L.

Development of a Size-Exclusion/Ion-Exclusion/Reversed-Phase Separation Method for the Simultaneous Determination of Inorganic and Organic Acids, Sugars, and Ethanol During Multiple Parallel Fermentation of Rice Wine

An effective method for monitoring the progress of rice wine fermentation (saccharification, glycolysis system, ethanol fermentation, and the TCA cycle) is required owing to the decreasing human resources in rice wine brewing and dramatically increasing export quantity of rice wine. This study aimed to develop an anion-exclusion/size-exclusion/reversed-phase chromatographic (AEC/SEC/RPC) separation protocol for the simultaneous determination of sugars, ethanol, inorganic, and organic acids for the effective monitoring of rice wine fermentation processes. Optimal chromatographic resolutions were obtained by the combination of a polymer-based size-exclusion column and H+-form weakly acidic cation-exchange resin column with a 20.0 mM phthalic acid eluent. The optimized AEC/SEC/RPC separation system determined 16 different species during rice wine fermentation in a single analysis. The developed AEC/SEC/RPC method demonstrated the below useful advantages for (1) evaluating the progress of rice wine fermentation; (2) evaluating the activity of brewing yeast from the behaviors of glucose, phosphate, and ethanol concentration; and (3) obtaining good correlation between the developed and official methods for monitoring glucose and ethanol. Consequently, several beneficial information was obtained for the process control of rice wine brewing by the developed method.

A Quantitative Method to Measure and Speciate Amines in Ambient Aerosol Samples

Ambient reactive nitrogen is a mix of nitrogen-containing organic and inorganic compounds. These various compounds are found in both aerosol- and gas-phases with oxidized and reduced forms of nitrogen. Aerosol-phase reduced nitrogen is predominately thought to include ammonium and amines. In ambient samples, the ammonium concentration is routinely determined, but the contribution of amines is not. We developed a method to discretely measure amines from ambient aerosol samples. It employs ion chromatography using a Thermo Scientific IonPac Dionex CS-19 column with conductivity detection and a three-step separation using a methanesulfonic acid eluent. This method allows for the quantification of 18 different amines, including the series of methylamines and the different isomers of butylamine. Almost all amines quantifiable by this technique were measured regularly when applying this method to ambient filter samples collected in Rocky Mountain National Park (RMNP) and Greeley, CO. The sum of the amines was ~0.02 µg m−3 at both sites. This increased to 0.04 and 0.09 µg m−3 at RMNP and Greeley, respectively, at the same time they were impacted by smoke. Analysis of separate, fresh biomass burning source samples, however, suggests that smoke is likely a minor emission source of amines in most environments.

ION CHROMATOGRAPHIC DETERMINATION OF YTTRIUM AFTER SEPARATION FROM DYSPROSIUM SIMULTANEOUSLY WITH INDIVIDUAL QUANTIFICATION OF RARE EARTH ELEMENTS

A particular ion chromatographic method for yttrium determination after separation from dysprosium simultaneously with individual quantification of rare earth elements has been modified. Selective separation of yttrium from dysprosium plus the other thirteen rare earth elements was achieved by gradient elution using oxalic / diglycolic acid eluent mixture on IonPac CS5A separating column. The separated ions were then detected using 4-(2-pyridylazo)resorcinol (PAR) at 530 nm. The optimized method was subsequently validated by the analysis of a reference sample from Abu Rusheid area followed by its application on two geological materials from Wadi Khuda-Wadi Shut area and Abu Tartour phosphate deposits. Relative standard deviation (RSD) calculated for the analyzed samples were expressed with very low values the matter which confirms the precision of the developed method. The present work allowed the individual determination of lanthanide elements including yttrium and six heavy metal ions in an absolute time of about 110 minutes.

Chromatographic separation and determination of some heavy metals and the sum of the rare earth elements in some geological materials

An ion chromatographic method for separation and determination of the sum of the rare earth elements in addition to the individual determination of some heavy metal ions has been developed. The separation has been performed on a mixed bed column, IonPac CS5A containing both anion and cation exchange sites. Selective separation of heavy metals was performed by isocratic elution using pyridine-(2,6)-dicarboxylic acid eluent followed by on-line elution of the total rare earth elements using oxalic acid eluent. Post-column spectrophotometric detection with 4-(2-pyridylazo) resorcinol was then coupled at 530 nm. The separation factors of the different ions were found to be dependent on the eluent concentration, the pH and to a much more extent on the flow rate. The optimized developed method has been validated by its application for the analysis of some heavy metals and the sum of the rare earth elements in a sample from Abu Rusheid mineralization that is considered as a reference material and has then been used for the analysis of two other samples represent two different localities one of which is from Gabal Gattar area while the other is from Abu Tartour phosphate deposits. The optimized method enabled the successful determination of both heavy metals and rare earth elements sum within a total analysis time of about 20 min with high reproducibility.

Preparation of difunctional polymer-based cation exchangers and their application in ion chromatography

Ion chromatography (IC) is one of the most important means for the separation and analysis of cationic compounds. Research on high-performance cation exchangers is of great significance for the advancement of modern IC techniques. Herein we proposed a newly developed modification method for polymer-based particles, based on thiol-radical-mediated polymerization. Specifically, acrylic acid and maleic anhydride were used as monomers and sodium 2-mercaptoethanesulfonate was used as the thiol modifier to prepare novel difunctional cation exchangers, functionalized with both carboxylic and sulfonic groups. With simple strong acid eluents, typical cations were well separated with good resolution. The retention behaviors of metal cations and organic amines on the cation exchangers were investigated using multiple chromatographic models. The good performances of the cation exchangers were also demonstrated by the gradient separation of ten cations within 24 min. The new method was easy to perform with high efficiency. Additionally, the cation exchange capacities of the cation exchangers were easily modulated by adjusting the initial content of the thiol modifier.

Multithiol functionalized graphene bio-sponge via photoinitiated thiol-ene click chemistry for efficient heavy metal ions adsorption

Heavy metals contamination in the natural waters remains an unresolved environmental challenge pressing for the development of purification technologies. This paper presents the green engineering of a new bio-sponge for heavy metals adsorption composed of alginate bio-polymeric network encapsulated with reduced graphene oxide (rGO) modified with iron oxide nanoparticles and covalently attached multithiol (pentaerythritol tetrakis-mercaptopropionate) molecules using photoinitiated thiol-ene click chemistry. The multithiol functionalized graphene bio-sponge (SH-Graphene bio-sponge) is designed to enhance adsorption performances of heavy metals including structural approach combined with oxygen functionalities and high density of sulfur-containing groups (10.2 at % S, confirmed by X-ray Photoelectron Spectroscopy, XPS) with high binding affinity towards specific heavy metals (Cd and Pb). It was shown that the level of thiol functionalization on the graphene structure within the bio-sponge can be controlled by tuning the Ultraviolet (UV) irradiation time without adjusting the concentration of the precursors. SH-functionalized graphene bio-sponge showed outstanding adsorption capacity for Pb (II): 101.01 mg/g and Cd (II): 102.99 mg/g, outperformed commercial and literature reported adsorbents in highly competitive selectivity studies using co-existing heavy metal ions (Cu, Co, Pb and Cd) spiked- sea water. The multithiol modified bio-sponge also showcased an excellent stability and reusability feature with only 0.015 mg/L Pb (II) detected, conforming the strict United States Environmental Protection Agency (US EPA) maximum contaminant level (MCL) for lead, after five recurring cycles using mixed heavy metal ions solution and acidic eluent. The outcomes from this work present valuable and promising contribution towards the development of a scalable and sustainable adsorbents for efficient remediation of heavy metals from waters.