Adsorption Of Heavy Metals Research Articles

Hydrogen Peroxide Modification Enhances the Ability of Metakaolin based Alkali Activated Materials Adsorbent to Remove the Ni2+ Ions

The presence of nickel ions in wastewater is a significant environmental concern due to its toxicity, which can cause severe health problems. Metakaolin is a pozzolanic material that can be activated by alkali to produce a highly porous and reactive material that can be utilised as a heavy metal ion adsorbent. However, the adsorption capacity of metakaolin-based adsorbents is limited by their surface chemistry and porosity. Metakaolin-based alkali-activated materials adsorbent modified with hydrogen peroxide can effectively remove nickel ions from wastewater. The modification process increases the surface area and porosity of the adsorbent, enhancing its adsorption capacity. The modified adsorbent (1.00 wt.% H2O2) showed a higher sorption capacity of 26.57 mg/g and efficiency of 85.22% compared to the non-modified adsorbent (10.55 mg/g) sorption capacity and 45.63% nickel removal efficiency, indicating the potential of hydrogen peroxide-modified adsorbents as an economical and ecologically sustainable solution for environmental applications, particularly for metal immobilization.

A short review of the sustainable utilization of coal gangue in environmental applications.

The production of coal gangue, a by-product of coal mining and washing, is rapidly increasing due to growing energy consumption. As the accumulated coal gangue has not been appropriately utilized, this has resulted in a squander of resources, waste disposal problems, and environmental pollution issues. However, coal gangue, a form of solid waste, exhibits various potential applications in the field of recycling. Currently, the processing capacity and utilization rate of coal gangue are insufficient to meet the demands of global low-carbon environmental protection. As such, this paper provides a detailed overview of the physical and chemical properties of coal gangue and its resource utilization methods in the environmental field, particularly in soil remediation, soil reclamation, the preparation of adsorbents for heavy metals, dyes, and CO2, and as catalysts for organic degradation and catalytic cracking. This review highlights the significance of coal gangue classification according to its properties for the comprehensive utilization of gangue. Additionally, we briefly introduce and discuss suggestions for future directions of research and development in this area. Nevertheless, with regard to the environmental impact of secondary pollution and the efficiency of coal gangue utilization, there remain numerous obstacles that hinder future research. This review is expected to provide significant insights into the development of coal gangue utilization strategies, potentially facilitating the efficient and practical large-scale management of solid waste.

Urban and Groundwater Microplastic Contamination: Sources, Distribution, Impacts, and Remediation Technologies

The presence of microplastics (MPs) in urban environments and groundwater systems has garnered significant global attention due to the critical role groundwater plays as a primary freshwater source. This review paper aims to comprehensively examine the sources, distribution, movement, and environmental impact of MPs, particularly focusing on urban areas and groundwater contamination. Special emphasis is placed on MPs originating from landfill leachate and their distribution along Malaysia's beaches. The paper also discusses the movement patterns of MPs, providing mathematical models for their migration. The environmental and health impacts of MPs, including soil degradation, toxicity in agricultural crops, and heavy metal adsorption, are analyzed. Additionally, current remediation technologies such as reverse osmosis, microbial exploitation, and ozonation are evaluated, with recommendations for combining different methods to enhance MP removal effectiveness. The involvement of the general public, socio-economic sectors, tourism, and waste management companies is highlighted as crucial for addressing this pervasive issue.

Unveiling heavy metal removal mechanisms in mulberry and rice husk biochars via sacrificial mineral descriptors.

Rice husk biochar (RBC) and mulberry biochar (MBC) have gained significant attention in the removal of heavy metals in aquatic environments. Their easy affordability and eco-friendly nature make these biochar's a powerful adsorbent for sustainable water remediation applications. Although their heavy metal adsorption characteristics of individual biochar's have been widely studied, a clear understanding of how the inherited mineral composition in RBC and MBC influences Pb2+, Cd2+, and Zn2+ removal in both deionized water (DIW) and Organization for Economic Co-operation and Development (OECD) water is currently lacking. In this study, heavy metal removal mechanisms of RBC and MBC in these water systems were investigated using various kinetic models and correlated them with their mineral composition. With the highest correlation coefficient of modified two-compartment first-order kinetic model (MTCFOKM), the measured qe values highlight MBC as a promising candidate for heavy metal removal in both acidic and alkaline conditions. pH edge experiments revealed significant differences in metal removal efficiency between these biochars, despite their similar specific surface areas and surface charges (pHpzc). XRD and FTIR characterization provided a strong support in explaining the high heavy metal removal ability of MBC stem from calcite mineral that inherited from biomass. Furthermore, the pH edge experiment combined with MINEQL+ speciation profiles revealed that heavy metal removal by MBC at low pH is linked to calcite leaching, shift in system pH, and heavy metal precipitation.

Preparation of bio‐based polyamide 56/chitosan heavy metal adsorbing nanocomposite fibers by electrospinning

AbstractElectrospinning technology can produce nanofibers with extremely high specific surface area. Bio‐based polyamide 56 (PA56) was combined with chitosan (CS) to prepare PA56/CS composite nanofibers. An in vitro mineralization experiment was conducted to obtain a super hydrophilic composite fiber (PA56/CS‐HAP) with hydroxyapatite deposited on the surface. The adsorption performance of the composite fiber (PA56/CS‐HAP) was evaluated by the adsorbent dosage, solution pH value, and adsorption kinetics. The curves obtained after fitting the kinetics and adsorption isotherms show that the adsorption behavior under pH = 6 is more consistent with the Langmuir adsorption model. The adsorption capacity in a 100 mg L−1 Pb2+ environment is more than 5 times that of 10 mg L−1. Bio‐based PA56/CS static‐spun nanocomposite fibers prepared by in vitro mineralization have great potential in environmental protection, sensors, chemical engineering, and other fields.Highlights PA/CS fibers were prepared by electrospinning. Hydroxyapatite was deposited by in vitro mineralization technique. PA/CS‐HAP fiber achieves super hydrophilic effect. The adsorption capacity of PA/CS‐HAP in 100 mg L−1 Pb(II) reached 27.5 mg g−1. After fitting, the adsorption process is consistent with Langmuir adsorption.

Synthesis of silicone material organo-cured with thiourea and methyl methacrylate for heavy metals adsorption from polluted water

Synthesis of silicone material organo-cured with thiourea and methyl methacrylate for heavy metals adsorption from polluted water

Advances in Microplastic Characterization: Spectroscopic Techniques and Heavy Metal Adsorption Insights

Advances in Microplastic Characterization: Spectroscopic Techniques and Heavy Metal Adsorption Insights

Clay-Based Materials for Heavy Metals Adsorption: Mechanisms, Advancements, and Future Prospects in Environmental Remediation

Given the severe threats posed by heavy metal pollution to ecological environments and human health, developing effective remediation technologies is of paramount importance. This review delves into the mechanisms, recent advancements, and future prospects of clay mineral-based materials in the adsorption of heavy metals. Clay minerals such as kaolinite, montmorillonite, and bentonite have demonstrated immense potential for the removal of heavy metals from water and soil due to their natural abundance, low cost, and high efficiency. This article summarizes the latest advancements in the adsorption of heavy metals like chromium, copper, lead, cadmium, arsenic and hydrargyrum by clay minerals, while examining how chemical and physical modifications can enhance the adsorption capacity, selectivity, and stability of these minerals. Furthermore, this review discusses how factors such as pH, temperature, and ionic strength affect adsorption efficiency and outlines challenges and future research directions for optimizing clay-based adsorbents in environmental applications.

Effects of particle size and aging on heavy metal adsorption by polypropylene and polystyrene microplastics under varying environmental conditions

Microplastics have become a major environmental issue because of their widespread presence and tendency to adsorb heavy metals, which can have harmful effects on aquatic ecosystems and human health. The present study investigates the adsorption mechanisms of Pb2+ and Cu2+ ions on both pristine and artificially aged microplastics (MPs) made of polystyrene (PS) and polypropylene (PP). Furthermore, the influence of MP size on the adsorption capacity under different environmental conditions was evaluated. According to the characterization of MPs, aging leads to physical damage and an increase in the number of oxygen-containing functional groups on their surface. The experimental results highlight the significantly higher adsorption ability of smaller and aged MPs compared with that of pristine MPs for both the heavy metal ions. The pseudo-second-order equation provided a better fit for the adsorption kinetics study (R2 = 0.95), suggesting that chemisorption governs the rate-limiting phase in the adsorption mechanism on the MP surfaces. The concordance between the adsorption isotherm model and Freundlich model (R2 > 0.95) indicated a predominance of multilayer adsorption. The environmental factors such as pH, humic acid, temperature, and SO42- concentration significantly affected the adsorption of Pb2⁺ and Cu2⁺ onto PP and PS MPs. These variables play a crucial role in determining the nature of the interactions between heavy metal ions and the microplastic particles under diverse environmental conditions. Electrostatic interactions, surface complexation and van der Waals forces were identified as two factors that could either improve or diminish the metal ion adsorption capacity of MPs.

Microwave Irradiation-Assisted Synthesis of Anisotropic Crown Ether-Grafted Bamboo Pulp Aerogel as a Chelating Agent for Selective Adsorption of Heavy Metals (Mn+)

Crown ether is widely used in water purification because of its ring structure and good selective adsorption of specific heavy metals. However, its high cost and difficulty in recycling limit the purification of heavy metals in water. The anisotropic [2,4]-dibenzo-18-crown-6-modified bamboo pulp aerogel (DB18C6/PA) is successfully synthesized by microwave irradiation and directional freezing technology. The physical and chemical properties of DB18C6/PA are analyzed by FTIR, XPS, SEM, TEM, TGA, surface area and porosity analyzers. Single or multivariate systems containing Pb2+, Cu2+ and Cd2+ are used as adsorbents. The effects of the DB18C6 addition amount, pH, initial concentration and adsorption temperature on the adsorption of DB18C6/PA are systematically explored. Pseudo-first-order kinetic models, pseudo-second-order kinetic models and the isothermal adsorption models of Langmuir and Freundlich are used to fit the experimental data. The adsorption selectivity is analyzed from the distribution coefficient and the separation factor, and the adsorption mechanism is discussed. The results show that anisotropic DB18C6/PA has the characteristics of 3D directional channels, high porosity (97.67%), large specific surface area (103.7 m2/g), good thermal stability and regeneration (the number of cycles is greater than 5). The surface has a variety of functional groups, including a hydroxyl group, aldehyde group, ether bond, etc. In the single and multivariate systems of Pb2+, Cu2+ and Cd2+, the adsorption process of DB18C6/PA conforms to the pseudo-second-order kinetic model, and the results conform to the Freundlich adsorption isothermal model (a few of them conformed to the Langmuir adsorption isothermal model), indicating that chemical adsorption and physical adsorption are involved in the adsorption process, and the adsorption process is a spontaneous endothermic process. In the single solution system, the maximum adsorption capacities of Pb2+, Cu2+ and Cd2+ by DB18C6/PA are 129.15, 29.85 and 27.89 mg/g, respectively. The adsorption selectivity of DB18C6/PA on Pb2+, Cu2+ and Cd2+ is in the order of Pb2+ >> Cu2+ > Cd2+.

Adsorption of Heavy Metals from Low Concentration Solutions onto Dried Chlamydomonas reinhardtii

Adsorption of Heavy Metals from Low Concentration Solutions onto Dried Chlamydomonas reinhardtii

Chankanai Zeolite Modified with Heteroatomic Derivatives of 3-Aminopropyltriethoxysilane as an Effective Sorbent for Ag(I), Co(II)

Bis-N,N-(3-triethoxysilylpropyl)thiosemicarbazide 3 was obtained by the condensation of 3-aminopropyltriethoxysilane 1 with thiosemicarbazide 2. Ethyl ether N-[3-(triethoxysilyl)propyl]-b-alanine 5 was obtained by the interaction of an equimolar amount of aminopropyltriethoxysilane 1 and ethyl acrylate 4 (aza-Michael reaction). Synthesized functional organosilanes 3 and 5 were successfully immobilized on the surface of natural zeolite Z (Chankanai deposit, Kazakhstan). Compounds and materials have been studied by NMR and IR Fourier spectroscopy and X-ray diffraction analysis. The elemental composition and morphology of modified zeolites Z3 and Z5 were studied using SEM-EDX analysis. The modification of zeolite by organosilanes 3 and 5 leads to changes in the surface structure of the material: with the enlargement of particles and agglomerates, the surface becomes more homogeneous and less porous. This indicates a high degree of zeolite coverage by the modifier layer. The study of the sorption characteristics of the initial Z and modified zeolites (Z3 and Z5) showed a high sorption capacity relative to Ag(I) and Co(II) (static sorption capacity, SSC = 35.85–23.92 mg/g), whereas the SSC values for Z were SSC = 20.63 and 16.64 mg/g. The adsorption of Ag(I) and Co(II) ions was studied in solutions prepared using Co(NO3)2·6H2O, AgNO3 and distilled water. The choice of the initial concentration of metal ions, as well as the pH of the solutions, corresponded to the composition of wastewater from real electroplating production. Zeolites Z3 and Z5 can be used in various sectors of industry, in ecology and for medical purposes as inexpensive and effective adsorbents (enterosorbents) of heavy and noble metals.

Treatment performance of different units in the anaerobic-anoxic-aerobic process of landfill leachate under antibiotic exposure

ABSTRACT The effectiveness of three different treatment units (anaerobic, anoxic, and aerobic) in A/A/O reactors when treating landfill leachate that contained varying concentrations of tetracycline (TC) was evaluated. The effluent quality, sludge performance, and removal rates of COD, TN, TP, and NH3-N of the reactors were investigated. The results showed that in the three treatment units (anaerobic, anoxic, and aerobic), when the TC dosage was 10 mg/L, the removal rates of NH3-N continued to decrease to 6.9%, 16.3%, and 32.8%, and the removal rates of COD, TN, and TP in the three treatment units reached their maximum values, which were 37.5%, 57.4%, and 69.6%; 21.1%, 37.1%, and 41.0%; 13.0%, 16.2%, and 27.4%, respectively. During the reactor's operation, the heavy metal content in the treatment units initially increased followed by a decrease, especially for Mn and Zn. This was due to the production of more EPS by microorganisms, resulting in more active sites for heavy metal adsorption. In addition, with the increase of TC concentration, TC removal rate was always positively correlated with PN, COD, TN and heavy metals removal rates, and negatively correlated with NH3-N, TP, pH, and PS. Further analysis revealed that TC was toxic to microorganisms, leading to a decrease in biodiversity and microbial community diversity among the three treatment units in the reactor. This article analyzed the treatment effects of different treatment units in leachate under antibiotic exposure conditions, to explore better external conditions for sewage biological treatment facilities.

Simulation, prediction and optimization for synthesis and heavy metals adsorption of schwertmannite by machine learning

Due to its sea urchin-like structure, Schwertmannite is commonly applied for heavy metals (HMs) pollutant adsorption. The adsorption influence parameters of Schwertmannite are numerous, the traditional experimental enumeration is powerless. In recent years, machine learning (ML) has been gradually employed for adsorbent materials, but there is no comprehensive research on the Schwertmannite adsorbent. In this paper, 27 features and 814 groups of experimental data were used to systematically analyze the adsorption modeling of Schwertmannite first time. The results indicated that the adsorption capacity of Schwertmannite was better predicted by the Random Forest (RF) model (the R2 was 0.874). Then, the RF model was used to analyze the features importance that affects the adsorption of HMs by Schwertmannite. And the importance of Schwertmannite synthesis conditions, Schwertmannite characteristics, adsorption environment, and HMs properties were 11.88%, 30.01%, 48.26%, and 8.19% respectively. Moreover, the synthesis and adsorption conditions of Schwertmannite were predicted and optimized based on RF model, it was predicted that the better synthesis method of Schwertmannite was biological oxidation > Fe2+ oxidation > Fe3+ hydrolysis. Finally, a predictive Graphical User Interface Web Page for Schwertmannite-HMs was developed. We hope that this paper can promote the integration of machine learning and Schwertmannite.

Magnetic nanoparticles for efficient heavy metal removal: synthesis, adsorption capacity, and key experimental parameters

Abstract Heavy metals are toxic, non-biodegradable pollutants that pose serious risks to human health and the environment, even at trace concentrations. The contamination of drinking water and groundwater by heavy metals requires urgent attention. Nanotechnology has advanced significantly over the past decade, offering innovative solutions for water purification, particularly through the adsorption of heavy metal ions using nanomaterials. This study focuses on the synthesis of magnetic nanoparticles, their adsorption capacity, and the desorption process. Additionally, the effects of key experimental parameters – such as contact time, ion concentration, pH, temperature, ionic strength, and adsorbent dose – on the removal efficiency of metal ions are examined. The findings underscore the potential of magnetic nanoparticles for effective heavy metal remediation in water.

The Effect of Different Aging Methods on the Heavy Metal Adsorption Capacity of Microplastics

The Effect of Different Aging Methods on the Heavy Metal Adsorption Capacity of Microplastics

Mg/Si- and Ag-Doped Carbon-Based Media Rainwater Filtration System for Multiple Pollutants Removal.

In this study, the removal performances of a multi-pollutant elimination cartridge system (MPECS) composed of palm shell waste-based activated carbon (PSAC), magnesium (Mg)/silicon (Si)-doped PSAC (Mg/Si-PSAC), and silver (Ag)-doped PSAC (Ag-PSAC) for heavy metals, organic pollutants, and Escherichia coli were investigated. Mg/Si impregnation significantly improved heavy metal removal using PSAC by increasing the surface area and adding more sorption sites to the magnesium silicate nanolayer. Fixed-bed column experiments showed that the MPECS column outperformed PSAC and commercial activated carbon (DJAC), with a 1.5 to 2.0 times higher E. coli removal and a higher removal of organic pollutants and heavy metals. The MPECS column, with its disinfection ability and adsorption of heavy metals and organic matter, is a promising system for removing multiple pollutants from rainwater.

Functionalized Cyclodextrin/Carboxymethyl Cellulose Composite Hydrogel with Double Network Structure for Adsorption of Heavy Metal Ions in Wastewater.

Heavy metal ions in industrial wastewater pose significant environmental and ecological threats. In this work, a hydrogel featuring a double network structure was synthesized via radical polymerization and cross-linking of β-cyclodextrin (CD) and carboxymethylcellulose (CMC) with acrylic acid (AA). The hydrogel's functional groups and microstructure were characterized using Fourier transform infrared spectroscopy (FTIR-ATR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Mechanical properties were evaluated through rheological and compression tests. The study examined the impact of initial metal ion concentration, adsorbent-ion contact time, and solution pH on adsorption capacity. The maximum adsorption capacities of the functionalized CD/CMC-PAA-MBA hydrogel for Cu2+, Pb2+, and Cd2+ ions were 158.12, 393.56, and 290.12 mg/g, respectively. Notably, the hydrogel exhibited the highest selectivity for Pb2+ in mixed solutions. The adsorption kinetics of the metal ions were modeled using the pseudo-second-order rate equation and the Langmuir adsorption isotherm.

Thermal Oxidation Degradation Characteristics and Kinetic Analysis of Waste Shell Powders for Efficient Utilization and Environmental Protection

ABSTRACT The thermal oxidation degradation and kinetic behavior of four waste shell powders: Hyriopsis cumingii, abalone, scallop, and clam were investigated. The thermal oxidation degradation process was elucidated using thermogravimetric analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and the Coats-Redfern method. This process typically occurs in four stages, with the decomposition of CaCO₃ (Stage III) being pivotal. Notably, clam and scallop powders exhibited the highest CaO yields of approximately 55.1% and 55.0%, respectively. Although abalone powder had a lower yield of 50.2%, it demonstrated the lowest activation energy of 118.08 kJ/mol in Stage III, suggesting potential energy and cost savings during CaO conversion. High-temperature calcination altered the chemical composition and microstructure of the shell powders, resulting in rough and porous CaO surfaces conducive to heavy metal ion and pollutant adsorption. The research provides a theoretical framework and experimental validation for the sustainable utilization of calcined shell powders, fostering efficient shell resource management and environmental protection.

Removal of Pb2+ in aqueous solution by diatom-derived biochar: Role of inherent Ca/Mg minerals

Mineral components can significantly enhance the adsorption capacity of contaminants on biochar, yet research on the changes in mineral crystal structure within biochar and their effects on adsorption performance remains limited. In this study, biochar was prepared from diatom, an abundant and eco-friendly biomass, at various pyrolysis temperatures. Adsorption experiments were conducted to evaluate the removal of Pb²⁺ using diatom-derived biochar under different conditions. The results indicated that the primary mechanism of Pb²⁺ removal involved ion exchange between the inherent Ca/Mg minerals and Pb²⁺, followed by the formation of PbCO₃ and Pb₂(CO₃)₂(OH)₂ on biochar surface. Inherent Ca/Mg minerals contributed 93.1 % to Pb2+ adsorption capacity. Additionally, adsorption capacity of Pb²⁺ were found enhanced with increased pyrolysis temperature, which was due to the change of inherent Ca-minerals crystal structure in diatom-derived biochar. Furthermore, diatom-derived biochar demonstrated excellent adsorption capacity for Pb²⁺ up to 1027.0 mg·g⁻¹. The adsorption kinetics fitted well with pseudo-second-order model, and the adsorption isotherm was well-described by the Langmuir model. An increase in pH favored the adsorption process. These findings suggest that diatom-derived biochar could serve as a promising adsorbent for heavy metals in water.