Pb Adsorption Capacity Research Articles

Effect of Microwave Irradiation on Lead Adsorption Properties of Vermiculite with Different Particle Sizes.

The expansion of vermiculite using microwave irradiation is an environmentally friendly and efficient method that can enhance the material's adsorption performance. This study investigated the microwave irradiation of vermiculite with five different particle sizes (4/2/1/0.5/0.2 mm) and found that the adsorption capacity for Pb2+ increased with larger particle sizes. The equilibrium adsorption capacity reached 15.98 mg/g at 4 mm, representing a 45.01% improvement compared to 0.2 mm. The pseudo-second-order kinetic model effectively described the adsorption kinetics. No significant differences were observed in the specific surface area and pore size distribution of all samples. Thermogravimetric quantitative analysis revealed that larger particle sizes retained interlayer water more effectively. As the particle size decreased, the interlayer water content generally showed a decreasing trend. Fourier-transform infrared spectroscopy analysis also indicated that the -OH groups in larger particle sizes exhibited higher stability. The results suggest that the high content and stability of -OH groups may be key factors in the enhanced adsorption performance for Pb2+. This provides new insights for the preparation of environmentally friendly adsorbent materials rich in hydroxyl groups.

Comparative kinetic study of Pb(II) and Cd(II) metal ions removal from aqueous solutions by Lactobacillus helveticus, Limosilactobacillus fermentum, and Lactiplantibacillus pentosus

ABSTRACT In this study, selected lactic acid bacteria, including Lactobacillus helveticus, Limosilactobacillus fermentum, and Lactiplantibacillus pentosus, were evaluated for their potential to remove Pb(II) and Cd(II) ions from aqueous solutions. The highest removal efficiency was achieved at a pH value of 4. Kinetic modeling using the pseudo-first-order, pseudo-second-order, and intraparticle diffusion models demonstrated that the intraparticle diffusion model provided the best fit for describing the adsorption process. The results of the study indicated that among the three bacteria tested, L. fermentum exhibited the highest maximum adsorption capacity for Pb(II) at 4.95 mg g−1, followed by L. helveticus at 4.91 mg g−1 and L. pentosus at 4.08 mg g−1. In contrast, for Cd(II) adsorption, L. helveticus showed the highest maximum adsorption capacity at 4.38 mg g−1, followed by L. pentosus at 3.45 mg g−1 and L. fermentum at 2.86 mg g−1. The mechanism of Pb(II) and Cd(II) ions removal by LAB strains involves adsorption onto the bacterial cell surfaces, where interactions such as ion exchange, electrostatic attraction, and complexation play crucial roles. Overall, L. helveticus, L. fermentum, and L. pentosus hold promising potential for various applications in wastewater treatment, particularly in the removal of heavy metal ions.

Synthesis of amidoxime adsorbent prepared by radiation grafting on upcycled low-density polyethylene sheet for removal of heavy metals from wastewater

The issue of discharging waste, especially heavy metals from industrial activities into the environment, not only adversely impacts environmental quality but also has impacts on communities and human health. Removal and reduction of heavy metal contamination in rivers and wastewater are, therefore, critical initiatives that require significant attention. This work studied the removal of heavy metals, including Zn(II), Cu(II), As(III), and Pb(II) by utilizing an upcycled amidoxime low-density polyethylene sheet (AO-sheet). The synthesized AO-sheet was analyzed for various physical properties, including scanning electron microscope, energy-dispersive x-ray spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. For the batch adsorption experiment, parameters affecting adsorption capacity were studied: initial concentration, submerging time, and pH. Adsorption isotherms were also studied. The results of the heavy metal adsorption study showed that the initial concentration was the most significant parameter; the higher the initial concentration, the greater the adsorption capacity. The adsorption capacity of Zn(II) and Pb(II) increased with submersion time, which achieved 21.07 and 0.855 mg/g-adsorbent, respectively, after four weeks of submersion under the highest initial concentration studied. The adsorption capacity of Cu(II) was 7.98 mg/g-adsorbent after two weeks of optimal adsorption duration under the highest initial concentration studied. The adsorption capacity of As(II) was 1.07 mg/g-adsorbent after one week of optimal submersion time under the highest initial concentration studied. Moreover, the appropriate pH range for effective adsorption of Zn(II), Cu(II), and Pb(II) was identified as 8–9, while for As(III), it was 6–8, with an adsorption duration of 0.43 weeks (3 days). From the Langmuir isotherm, it was found that the adsorption of this work was characterized by monolayer adsorption. The results demonstrate that the AO-sheet can be effectively used to remove heavy metals from wastewater. Its potential for reusability was up to 8 cycles, with the Zn(II) adsorption capacity being reduced to about 20.37%.

Kenaf Biochar as an Eco‐Friendly Adsorbent for Removal of Cu(II) and Pb(II): Optimal Temperature, Adsorption Models, and Efficiency Evaluation

ABSTRACTThis study examined the adsorption capacities of biochars derived from kenaf (KF‐BCs) for the removal of heavy metals such as Cu(II) and Pb(II). The thermal decomposition temperature (300–750°C) significantly influenced the morphology and composition of KF‐BCs, enhancing their surface area, pore structure, and alkalinity. Among them, kenaf pyrolyzed at 750°C (KF‐750) was the most effective in removing Cu(II) and Pb(II), as validated by kinetic, equilibrium, and isotherm model analyses. Adsorption kinetics revealed that equilibrium was attained after 24 h, with chemisorption governing the process rate. Equilibrium adsorption conformed to the Langmuir and Freundlich models for Cu(II) and Pb(II), respectively. KF‐750 exhibited midrange adsorption capacities for Cu(II) and Pb(II) (23.47 ± 0.3 mg/g and 50.07 ± 0.9 mg/g, respectively), compared with the literature. The thermodynamic assessment revealed an endothermic process with positive ∆H0, indicating that higher temperatures favor metal adsorption. At low pH, adsorption decreased due to electrostatic repulsion, particularly affecting Cu(II). More than 99.8% of Cu(II) and Pb(II) were removed with a 5.00 g/L KF‐750 dose. The cation effect order on KF‐750 was Ca2+ > Mg2+ > Na+ > K+. Overall, KF‐750 demonstrates promising potential as an adsorbent for the efficient heavy metal removal from aqueous solutions, presenting a viable option for environmental remediation.

Effective and green in-situ remediation strategies based on TEMPO-nanocellulose/lignin/MIL-100(Fe) hydrogel nanocomposite adsorbent for lead and copper in agricultural soils

Hydrogel adsorbents are promising tools for reducing heavy metals' bioavailability in contaminated soil. However, their practical feasibility remains limited by the low stability, inefficient removal efficiency, and potential secondary pollution. Optimizing the adsorption operation and the functional properties of hydrogel adsorbents could eliminate this method's drawbacks. Herein, three innovative in-situ remediation strategies for Pb/Cu-contaminated soil were adopted based on the concept of novel TEMPO-cellulose (TO-NFCs)/lignin/acrylamide@MIL-100(Fe) nanocomposite hydrogel adsorbent (NCLMH). Characteristic analyses revealed ideal Pb/Cu adsorption mechanisms by swelling, complexation, electrical attraction, and ion exchange via carboxyl/hydroxyl/carbonyl groups and unsaturated Fe(III) sites on ANCMH besides FeOOH formation. The highest maximum theoretical adsorption capacities of Pb(II) and Cu(II) on ANCMH were 416.39 and 133.98 mg/g, under pH 6.5, governed by pseudo-second-order/Freundlich models. Greenhouse pot experiments with contaminated soils amended with two-depth layers of 0.5% NCLMHs (SA@NCLMH) displayed a decline in Pb and Cu bioavailability up to 85.9% and 74.5% within 45 d. Soil column studies simulating continuous water soil flushing coupled with NCLMH layers, instead of conventional extractant fluids, and connected to NCLMH-sand column as purification unit (CF@NCLMH) achieved higher removal rates for Pb, and Cu of 89.5% and 77.2% within 24 h. Alternatively, conducting multiple-pulse soil flushing mode (MF@NCLMH) gained the highest Pb and Cu removal of 96.5% and 85.4%, as the water flushing-stop flux events allowed adequate water movement/residence period, promoting Pb/Cu desorption-adsorption from soil to NCLMH. Also, the NCLMH-sand column conducting and easy separation of the stable/reusable NCLMHs prevented the potential secondary pollution. Interestingly, the three remediated soils reached the corresponding regulation of the permissible limits for Pb and Cu residential scenarios in medium-to-heavily agricultural polluted soils, alleviating the Pb/Cu bioaccumulation and phytotoxicity symptoms in cultivated wheat, especially after MF@NCLMH treatment. This study introduces promising alternative remediation strategies with high sustainability and feasibility in acidic-to-neutral heavy metal-contaminated agricultural soil.

Carrier effects of face mask-derived microplastics on metal ions: Enhanced adsorption by photoaging combined with biofilms, exemplified with Pb(Ⅱ)

Face masks have emerged as a significant source of microplastics (MPs) under the influence of biotic and abiotic interactions. However, the combined effects of abiotic photoaging and biofilm-loading on mask-derived MPs as carriers of metal ions are not clear. We investigated the Pb(Ⅱ) adsorption onto polypropylene (PP) and polyurethane (PU) mask-derived MPs treated by photoaging, biofilm-loading, and both combinations, evaluating the composite risks. PU mask-derived MPs (1.157.47 mg/g) exhibited greater Pb(Ⅱ) adsorption capacity than PP mask-derived MPs (0.842.08 mg/g) because of the presence of intrinsic carbonyl functional groups. Photoaging (30.5%, 88.4%), biofilm-loading (110.7%, 87.1%), and both combinations (146.7%, 547.0%) of PP and PU masks enhanced Pb(Ⅱ) adsorption compared to virgin mask-derived MPs due to the increase of oxygen-containing functional groups. High-throughput sequencing indicated that the structural morphology and chemical composition of masks significantly affected the microbial community. Adsorption mechanisms involved electrostatic force and surface complexation. A combination of photoaging and biofilms increased the ecological risk index of mask-derived MPs in freshwater, showing the risk level to be high (PP mask) and very high (PU mask). This research highlights the crucial role of photoaging combined with biofilms in controlling metal ion adsorption onto mask-derived MPs, thereby increasing the composite risks.

Enhanced performance of amine and thiol chemically modified graphene oxide for effective removal of Hg(II), Pb(II), and Cr(VI) from aqueous solution

This study describes a novel adsorbent with a multidentate ligand that was facilely fabricated by covalently bonding 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole on graphene oxide (AHMT-PRGO). The AHMT-PRGO nano-adsorbent was used for the effective removal of Hg(II), Pb(II), and Cr(VI) from wastewater. The AHMT-PRGO nano-adsorbent was synthesized by a nucleophilic substitution reaction between GO acyl chloride and AHMT chelating ligand in the presence of tetrabutyl-ammonium bromide as a catalyst. The successful modifications were confirmed via several spectroscopic and electron microscopy instrumentations including UV–Vis, FTIR, Raman, XRD, XPS, SEM, and TEM. The maximum adsorption capacities of Hg(II), Cr(VI), and Pb(II) on the AHMT-PRGO nano-adsorbent were 370.0, 136.2, and 109.6 mg/g, respectively, exceeding those of most previously reported adsorbents. Additionally, the equilibrium contact times for Hg(II), Pb(II), and Cr(VI) were 60, 30, and 400 min, respectively. In a mixture of nine heavy metal ions containing 250 ppm of each ion, the AHMT-PRGO nano-adsorbent exhibited high selectivity for Hg(II) ions. Furthermore, the AHMT-PRGO nano-adsorbent showed high stability over five adsorption–desorption cycles. Additionally, the AHMT-PRGO nano-adsorbent was successfully applied to remove heavy metal ions from real water samples. The novelty of AHMT-PRGO lies in the combination of a multidentate ligand for strong and selective binding with the high surface area and stability offered by covalently bonded graphene oxide. This combination offers potential advantages over traditional adsorbents in terms of adsorption capacity, selectivity, and reusability.

Efficient removal of Pb(II) and Cd(II) ions from wastewater using amidoxime functionalized graphene oxide

AbstractThis study aimed to develop iminodiethylamine oxime graphite oxide (IOGO) through the grafting of iminodiethylamine oxime onto graphene oxide (GO) via amidation and oximation. The primary objective was to investigate the adsorption characteristics of Pb(II) and Cd(II) ions on IOGO. Results demonstrated that IOGO exhibited exceptional adsorption capabilities, reaching maximum adsorption capacities of 798.87 mg/g for Pb(II) and 283.50 mg/g for Cd(II). Remarkably, IOGO maintained its high adsorption performance over five consecutive adsorption cycles. Specifically, the adsorption capacity for Pb(II) remained significantly stable at 480.78 mg/g, exhibiting only an 8.77% decrease. Similarly, the Cd(II) adsorption capacity remained robust at 204.13 mg/g, demonstrating a modest reduction of 10.47%. These findings underscore the feasibility of employing IOGO in repeated adsorption processes, thereby showcasing its potential for practical applications in the removal of heavy metals from aqueous solutions.

Effective Removal of Pb(II) from Multiple Cationic Heavy Metals—An Inexpensive Lignin-Modified Attapulgite

To develop cost-effective heavy metal adsorbents, we employed water-soluble lignin from black liquor to modify activated attapulgite, resulting in the creation of a novel adsorbent called Lignin-modified attapulgite (LATP). In this study, scanning electron microscopy and Fourier transform infrared spectrometer techniques were utilized to characterize the structural details of LATP. The results revealed that lignin occupies the micropores of attapulgite, while additional functional groups are present on the attapulgite surface. We conducted adsorption tests using LATP to remove five types of heavy metal ions (Cd2+, Pb2+, Zn2+, Mn2+, Cu2+), and it was found that LATP exhibited greater removal mass and binding strength for Pb(II) compared to the other ions. For further investigation, batch experiments were performed to evaluate the adsorptive kinetics, isotherms, and thermodynamics of Pb2+ removal from aqueous solutions using LATP. The results indicated that the adsorption capacity of Pb(II) on LATP decreased with decreasing pH, while the presence of Na+ had no effect on adsorption. The adsorption process reached equilibrium rapidly, and the Langmuir adsorption capacities increased with temperature, measuring 286.40 mg/g, 315.51 mg/g, and 349.70 mg/g at 298 K, 308 K, and 318 K, respectively. Thermodynamic analysis revealed positive values for ΔH0 and ΔS0, indicating an endothermic and spontaneous adsorption process. Furthermore, ΔG0 exhibited negative values, confirming the spontaneous nature of the adsorption. Consequently, LATP demonstrates great potential as an effective adsorbent for the removal of Pb(II). Therefore, LATP shows great potential as an effective adsorbent for the removal of Pb(II) from natural water environments, contributing to the sustainable development of man and nature.

Preparation of 6-Amino-N-hydroxyhexanamide-Modified Porous Chelating Resin for Adsorption of Heavy Metal Ions.

The pollution of water bodies by heavy metal ions has recently become a global concern. In this experiment, a novel chelating resin, D851-6-AHHA, was synthesized by grafting 6-amino-N-hydroxyhexanamide (6-AHHA) onto the (-CH2N-(CH2COOH)2) group of the D851 resin, which contained a hydroxamic acid group, amide group, and some carboxyl groups. This resin was developed for the purpose of removing heavy metal ions, such as Cr(III) and Pb(II), from water. The findings from static adsorption experiments demonstrated the remarkable adsorption effectiveness of D851-6-AHHA resin towards Cr(III) and Pb(II). Specifically, the maximum adsorption capacities for Cr(III) and Pb(II) were determined to be 91.50 mg/g and 611.92 mg/g, respectively. Furthermore, the adsorption kinetics of heavy metal ions by D851-6-AHHA resin followed the quasi-second-order kinetic model, while the adsorption isotherms followed the Langmuir model. These findings suggest that the adsorption process was characterized by monolayer chemisorption. The adsorption mechanism of D851-6-AHHA resin was comprehensively investigated through SEM, XRD, FT-IR, and XPS analyses, revealing a high efficiency of D851-6-AHHA resin in adsorbing Cr(III) and Pb(II). Specifically, the (-C(=O)NHOH) group exhibited a notable affinity for Cr(III) and Pb(II), forming stable multi-elemental ring structures with them. Additionally, dynamic adsorption experiments conducted using fixed-bed setups further validated the effectiveness of D851-6-AHHA resin in removing heavy metal ions from aqueous solutions. In conclusion, the experimental findings underscored the efficacy of D851-6-AHHA resin as a highly efficient adsorbent for remediating water bodies contaminated by heavy metal ions.

Adsorption of Pb(II) in water by modified chitosan-based microspheres and the study of mechanism

In this study, a fresh three-dimensional microsphere adsorbent (CATP@SA3) was successfully synthesized by Attapulgite (ATP) and combining Chitosan (CS), incorporating them into a Sodium alginate (SA) solution, and crosslinking them in a CaCl2 solution. Multiple analyses, including XRD, TGA, FTIR, XPS, SEM-EDS, and BET were utilized to comprehensively characterize the structural makeup of CATP@SA3. These analyses revealed the presence of beneficial functional groups like hydroxyl, amino, and carboxyl groups that enhance the adsorption efficiency in adsorption procedures. CATP@SA3 was evaluated by studying different factors, including material ratio, contact time, dosage, solution pH, Pb(II) concentration, temperature, ionic strength, and aqueous environment. Three adsorption models, including kinetic, isotherm, and thermodynamic, were fitted to the experimental data. The findings demonstrated that the maximum Pb(II) adsorption capacity of CATP@SA3 was 1081.36 mg/g, with a removal rate that exceeded 70 % even after 5 cycles of use. Furthermore, correlation adsorption models revealed that the adsorption process of Pb(II) with CATP@SA3 was driven by a chemical predominantly reaction.

Adsorptive removal of Pb(II) ions from aqueous effluents using O-carboxymethyl chitosan Schiff base-sugarcane bagasse microbeads

In this study, a novel and cost-effective approach was employed to prepare an effective Pb(II) adsorbent. We synthesized highly porous CMCSB-SCB microbeads with multiple active binding sites by combining carboxymethylated chitosan Schiff base (CMCSB) and sugarcane bagasse (SCB). These microbeads were structurally and morphologically characterized using various physical, analytical, and microscopic techniques. The SEM image and N2-adsorption analysis of CMCSB-SCB revealed a highly porous structure with irregularly shaped voids and interconnected pores. The CMCSB-SCB microbeads demonstrated an impressive aqueous Pb(II) adsorption capacity, reaching a maximum of 318.21 mg/g, under identified optimal conditions: pH 4.5, 15 mg microbeads dosage, 30 min contact time, and Pb(II) initial concentration (350 mg/L). The successful adsorption of Pb(II) onto CMCSB-SCB beads was validated using FTIR, EDX, and XPS techniques. Furthermore, the experimental data fitting indicated a good agreement with the Langmuir model (R2 = 0.99633), whereas the adsorption kinetics aligned well with the pseudo-second-order model (R2 = 0.99978). The study also identified the Pb(II) adsorption mechanism by CMCSB-SCB microbeads as monolayer chemisorption.

Lead stabilization and remediation strategy with soil amendment in situ immobilization in contaminated range lands

In situ immobilization is a potential approach that can be used to remediate low-to-medium levels of heavy-metal in contaminated-soil. There is little known about how modifications to soil characteristics may affect Pb’s release from soil. The four different amendments, triple-superphosphate and attapulgite were combined in Ad-1; zeolite and triple-superphosphate were in Ad-2; hydroxyapatite and humus were in Ad-3; and nano-carbon. These amendments are mostly made of phyllosilicate minerals, humus, base minerals, and nano-carbon, respectively. Results revealed that the test amendments’ maximal Pb-adsorption capacity varied from 7.47 to 17.67 mg g−1. Surface precipitation and ion-exchange were found to be the main mechanisms for Pb-adsorption by Ad-1 and Ad-2, while Ad-3 and Ad-4 were promising among the all, according to analysis of the modifications both before and after Pb loading. When the pH dropped (7-1) or the ion-strength rose (0–0.2 M), there was a discernible rise in the Pb-desorption percentages from the amendments. It was determined that Ad-3 and Ad-4 were more effective in situ immobilizing lead in contaminated-soils because of their high adsorption capacities (12.82 and 17.67 mg g−1) and low-desorption percentages (4.46–6.23%) at ion-strengths of 0.01–0.1 mol L−1 and pH levels ranging from 5 to 7.

Two-step recovery of Pb(II) and Cd(II) with thiophene functionalized hydrogel from lead-acid battery wastewater: Insight into pH-regulated separation

Lead-acid batteries (LAB) are one of the most harmful batteries to the environment and human health. LAB wastewater contains Pb(II) and Cd(II), meanwhile, strongly acidic media (pH ≤ 3.0) poses a serious threat to ecological safety and human health. Herein, a novel thiophene functionalized biomass-based hydrogel (PEITC-SA) containing various groups was prepared by a two-step synthesis strategy involving liquid-phase modification and dopant-induced crosslinking. The static experiments relating to selectivity, kinetics and equilibria confirmed that PEITC-SA not only had a high adsorption capacity and selectivity for Pb(II) at pH 2.0, but also had a good adaptability for both Pb(II) and Cd(II) at pH 3.0. Moreover, the coexistence of inorganic salts and organic compounds had little effect on the adsorption of Pb(II) and Cd(II). Complexation was confirmed as the main adsorption force at pH 2.0, meanwhile at pH 3.0, electrostatic interaction, ion exchange interaction and complexation were all involved. According to Density Functional Theory calculations, tetradentate coordination of thiophene and amino groups was the most stable. Dynamic column experiments towards simulated LAB wastewater demonstrated the high efficiency and feasibility of pH-regulated fractional treatment, which of unexpected economic prospects. Furthermore, PEITC-SA could be easily desorbed with dilute HCl solution. Therefore, PEITC-SA possessed satisfactory potential for the resource recovery towards LAB wastewater through pH-regulated two-step separation.

Acetate anions intercalated Fe/Mg-layered double hydroxides modified biochar for efficient adsorption of anionic and cationic heavy metal ions from polluted water

The simultaneous removal of anionic and cationic heavy metals presents a challenge for adsorbents. In this study, acetate (Ac-) was utilized as the intercalating anion for layered double hydroxide (LDH) to prepare a novel biochar composite adsorbent (Ac-LB) designed for the adsorption of Pb(II), Cu(II), and As(V). By utilizing Ac- as the intercalating anion, the interlayer space of the LDH was enlarged from 0.803 nm to 0.869 nm, exposing more adsorption sites for the LDH and enhancing the affinity for heavy metals. The results of the adsorption experiments showed that the adsorption effect of Ac-LB on heavy metals was significantly improved compared to the original FeMg-LDH modified biochar composites (LB), and the maximum adsorption capacity of Pb(II), Cu(II), and As(V) were 402.70, 68.50, and 21.68 mg/g, respectively. Wastewater simulation tests further confirmed the promising application of Ac-LB for heavy metal adsorption. The analysis of the adsorption mechanism revealed that surface complexation, electrostatic adsorption, and chemical deposition were the main mechanisms of action between heavy metals (Pb(II) and Cu(II)) and Ac-LB. Additionally, Cu(II) ions underwent a homogeneous substitution reaction with Ac-LB. The adsorption process of As(V) by Ac-LB mainly relied on complexation and ion-exchange reactions. Lastly, the modification of the LDH structure by Ac− as an intercalating anion, thereby increasing the affinity for heavy metals, was further illustrated using density-functional theory (DFT) calculations.

Pb(II) Adsorption Properties of a Three-Dimensional Porous Bacterial Cellulose/Graphene Oxide Composite Hydrogel Subjected to Ultrasonic Treatment.

A three-dimensional porous bacterial cellulose/graphene oxide (BC/GO) composite hydrogel (BC/GO) was synthesized with multi-layer graphene oxide (GO) as the modifier and bacterial cellulose as the skeleton via an ultrasonic shaking process to absorb lead ions effectively. The characteristics of BC/GO were investigated through TEM, SEM, FT-IR, NMR and Zeta potential experiments. Compared to bacterial cellulose, the ultrasonic method and the carboxyl groups stemming from GO helped to enhance the availability of O(3)H of BC, in addition to the looser three-dimensional structure and enriched oxygen-containing groups, leading to a significantly higher adsorption capacity for Pb(II). In this paper, the adsorption behavior of BC/GO is influenced by the GO concentration, adsorption time, and initial concentration. The highest adsorption capacity for Pb(II) on BC/GO found in this study was 224.5 mg/g. The findings implied that the pseudo-second-order model explained the BC/GO adsorption dynamics and that the data of its adsorption isotherm fit the Freundlich model. Because of the looser three-dimensional structure, the complexation of carboxyl groups, and the enhanced availability of O(3)H, bacterial cellulose exhibited a much better adsorption capacity.

Sustainable Solutions for Heavy Metal Contamination: Characterization and Regeneration of Water Hyacinth Biosorbent in Wastewater Treatment

<p>The water hyacinth biosorbent has undergone thorough characterization and assessment for its capacity to remove heavy metals, specifically Pb(II) and Hg(II), from aqueous solutions. Notably, the biosorbent demonstrated an impressive maximum adsorption capacity for Pb and Hg, reaching values of 158.7 mg/g and 123.5 mg/g, respectively. Indeed, these adsorption capacities align with or even surpass those documented in the existing literature for various biosorbents derived from similar agro-industrial waste materials. Several methods were used to characterize the water hyacinth biosorbent's structure and morphology, including pH-Zero Point Change, scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS), and infrared spectrometry with Fourier transform (FT-IR). The water hyacinth biosorbent was found to have broken exteriors with mixed particles that involved useful adsorption clusters such as OH, C=O, and C-O-C. The most effective adsorption of Pb(II) and Hg(II) takes place at a pH of 5.0, using a hyacinth dose of 2 g/L. The chemisorption process is the primary cause of the fast growth rate of the adsorption process, which is governed by pseudo-second-order kinetics. Using a 0.1M HNO3 eluent, both biosorbents were effectively regenerated, enabling effective reuse for up to five cycles. The thermodynamic studies confirm the endothermic nature of the adsorption process.</p>

Synthesis of Chitosan Silica Membrane from Petung Bamboo (<i>Dendrocalamus asper</i>) Leaves and Its Application as Pb(II) Metallic Adsorbent

Membrane synthesis through a phase inversion method using chitosan and sodium silicate solutions has been conducted. This research aims to characterize the silica chitosan membrane (SCM) of petung bamboo leaves and determine the synthesized product's adsorption capacity for Pb(II) ions. The XRF characterization showed the silica content of petung bamboo leaves with a percentage of 78.03%. SEM analysis before adsorption is around 13.0 μm, and the pore diameter after adsorption is around 9.7 μm. The results of adsorption analysis of Pb(II) metal using AAS showed that the SCM variation A at an initial concentration of 10.0000 ppm Pb(II) metal adsorbed was 9.8101 ppm, and at an initial concentration of 25.0000 ppm Pb(II) metal was 22.3421 ppm. The variation B at an initial concentration of 10.0000 ppm Pb(II) metal adsorbed was 9.8870 ppm and at an initial concentration of 25.0000 ppm Pb(II) metal adsorbed was 23.5806 ppm. The variation C at an initial concentration of 10.0000 ppm Pb(II) metal adsorbed was 9.9639 ppm, and at an initial concentration of 25.0000 ppm Pb(II) metal was 24.1855 ppm. The results of this research conclude that the highest SCM adsorption power is variation C (2%:22.95%) with a percentage of 99.63%.

Functionalization of Strontium Ferrite Nanoparticles with Novel Chitosan–Schiff Base Ligand for Efficient Removal of Pb(II) Ions from Aqueous Media

Lead contamination in water poses significant health risks, making its removal imperative. In this study, magnetic strontium ferrite (SrFe12O19) nanoparticles were facilely synthesized by the Pechini sol–gel method and subsequently functionalized with a novel chitosan–Schiff base ligand to obtain a novel inorganic/organic nanocomposite for removing Pb(II) ions from aqueous solutions. The chitosan–Schiff base ligand was synthesized through the reaction of chitosan with 2,4,5-trihydroxybenzaldehyde. The presence of two X-ray diffraction (XRD) peaks at 2Ɵ = 10.5° and 2Ɵ = 20.5°, alongside the characteristic SrFe12O19 peaks, confirmed the functionalization of the nanoparticles with the ligand. Additionally, a significant decrease in the saturation magnetization value from 40.29 emu/g in pure SrFe12O19 nanoparticles to 17.32 emu/g in the nanocomposite further verified the functionalization. The presence of carbon (C) and nitrogen (N) atoms in the energy-dispersive X-ray (EDX) pattern of the nanocomposite, in addition to iron (Fe), strontium (Sr), and oxygen (O), also confirmed the functionalization. The nanocomposite’s maximum adsorption capacity for Pb(II) ions was 390.63 mg/g. Moreover, the adsorption process is endothermic, spontaneous, and chemical, occurring via complexation with -C=N and -OH groups, and it fits well with the Langmuir equilibrium isotherm and the pseudo-second-order kinetic equation.

Selective separation of lead (II) from foodstuffs and environmental samples by adsorption onto modified truffle peels with nanoparticles [TPs/TiO2(NP)] as a novel biomass

ABSTRACT This study aims to examined truffle peel powder modified with nanoparticles [TPs/TiO2(NP)] as a solid adsorbent for the removal of lead ions Pb(II) from environmental media and foodstuffs. The characterisation of TPs/TiO2(NP) was studied by a Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and energy dispersive X-ray (EDX). Through the application of several adsorption isotherm models, the Langmuir at 25°C revealed to be most appropriate, having the highest R2 (0.961), and the maximum Pb(II) adsorption capacity was found 0.908 mg g−1. In addition, the various kinetics models were applied, and the data was well-fitted by the pseudo-second order kinetics model (R2 = 0.9997). Thermodynamic parameters indicated that the technique of adsorption had been endothermic (∆H = 30.79 J mol−1), The value of ΔG indicates the spontaneous and physical nature (- 29.26 KJ mol−1) and the positive value of ∆S indicates a moderate step of sorption of the Pb(II) complex ion associate (98.32 J). Foodstuffs (energy drinks and ice pops) and environmental samples (tap water) were successfully confirmed with a good recovery.