Removal Of Toxic Ions Research Articles

Adsorptive Removal of Cd(II) Ions from Water by a Cheap Lignocellulosic Adsorbent and Its Reuse as a Catalyst for the Decontamination of Sulfamethoxazole.

The work reports the removal of cadmium from water by applying an efficient low-cost lignocellulosic adsorbent, rooibos tea waste. The cadmium-loaded rooibos tea waste was used for the photocatalytic abatement of sulfamethoxazole to cater to the setback of secondary pollution mostly associated with the adsorption technique. The rooibos tea waste adsorbent displayed a high removal efficiency of about 90.63% for 10 mg/L Cd(II) ions at 45 °C, 180 min agitation time, pH 7, and a dosage of 500 mg. The process of Cd(II) adsorption was endothermic and spontaneous. Also, the spent adsorbent was found to be efficient toward the photocatalytic breakdown of 10 mg/L sulfamethoxazole with a degradation efficiency of 69% after 150 min. In addition, the extent of mineralization of the sulfamethoxazole by the spent adsorbent as obtained from the total organic carbon data was found to be 53%. Therefore, based on the results obtained from this work, rooibos tea waste lends itself as a cheap, eco-friendly, easily sourced, and viable adsorbent for the removal of toxic ions like Cd(II). Also, the successful reuse of the spent adsorbent is a promising approach to cater to the major setback of secondary pollution associated with adsorption technology.

Redox flow deionization using Prussian blue and functionalized ion exchange membrane for enhanced selective ion recovery

Flow electrode capacitive deionization (FCDI) is a newly developed water treatment technology that offers better performance than the original, solid electrode capacitive deionization (CDI). By eliminating the need for discharging process, FCDI provides much higher desalination capacity with a continuous desalination operation. Along with applications for salt removal, selective removal and recovery of specific ions are also prominent features of FCDI technology. Characteristics of electrodes and ion exchange membranes play a crucial role in controlling the selectivity of ions in an FCDI system. In this study, we demonstrated selective and continuous ion recovery by combining redox-active Prussian blue as flow electrodes and functionalized ion exchange membranes in FCDI configuration. Prussian blue selectively absorbs monovalent Na+ ions from Na+/Ca2+ mixtures through intercalation reaction, in which a smaller Stokes radius of Na+ ion is more favored to fit in the crystal lattice. Furthermore, such selectivity is much more enhanced through functionalization of a cation-exchange membrane (CEM) with polymer multilayers. A layer-by-layer method was used to deposit poly(allylamine hydrochloride) (PAH) and poly(styrene sulfonate) (PSS) on the CEM. Results showed that polymer multilayers changed the CEM from divalent to monovalent ion-affinity due to different ion sizes and charge density. The combination of Prussian blue and functionalized CEM raised the selectivity for sodium around 17 times compared to a control system (0.2 to 3.35). We believe that our approach can provide insight into various areas including resource production, recovery, removal of toxic ions, and material recycling using an FCDI system.

Exogenous Xyloglucan Oligosaccharides Alleviate Cadmium Toxicity in Boehmeria nivea by Increasing the Cadmium Fixation Capacity of Cell Walls

Xyloglucan is an important component of hemicellulose, and xyloglucan oligosaccharides (Xh), which are metabolized by xyloglucan, play an important role in plant growth and development. However, the regulatory effects of the external application of Xh under cadmium (Cd) stress have not been determined. In this study, we evaluated the mechanism by which Xh contributes to resistance to Cd stress in ramie, a candidate plant species for toxic ion removal. The external application of Xh effectively attenuated the effects of Cd on ramie growth and photosynthetic pigments. Cd stress can also inhibit the activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX), resulting in a significant increase in the extent of membrane lipid peroxidation. After the external application of Xh, antioxidant enzyme activity was up-regulated, and damage to membranes in plants was reduced. In addition, the external application of Xh increased Cd retention in roots, thereby significantly decreasing Cd content in shoots. The external application of Xh also regulated the subcellular distribution of Cd and increased the Cd content of the cell wall. In particular, a root cell wall analysis revealed that Cd+Xh treatment significantly increased the hemicellulose content in the cell wall and the amount of Cd retained. In summary, the external application of Xh alleviates Cd toxicity in ramie by increasing the hemicellulose content and the Cd fixation ability of the cell wall and by reducing membrane lipid peroxidation via antioxidant enzymes.

Stimuli-Responsive Ion Adsorbents for Sustainable Separation Applications.

Stimuli-responsive ion absorbents (SRIAs) with reversible ion adsorption and desorption properties have recently attracted immense attention due to their outstanding functionalities for sustainable separation applications. Over the past decade, a series of SRIAs that respond to single or multiple external stimuli (e.g., pH, gas, temperature, light, magnetic, and voltage) have been reported to achieve excellent ion adsorption capacity and selectivity while simultaneously allowing for their reusability. In contrast to traditional adsorbents that are mainly regenerated through chemical additives, SRIAs allow for reduced chemical and even chemical-free regeneration capacities, thereby enabling environmentally friendly and energy-efficient separation technologies. In this review, we systematically summarize the materials and strategies reported to date for synthesizing single-, dual-, and multiresponsive ion adsorbents. Following a discourse on the fundamental mechanisms that govern their adsorption and desorption under various external stimuli, we provide a concise discussion of the regeneration capacity and application of these responsive ion adsorbents for sustainable water desalination, toxic ion removal, and valuable ion extract and recovery. Finally, we discuss the challenges in developing and deploying these promising multifunctional responsive ion adsorbents together with strategies to overcome these limitations and provide prospects for their future.

DFT calculation and experimental study of nitrogen-doped carbon nanotube nanocomposite in As+3 toxic ions removal

DFT calculation and experimental study of nitrogen-doped carbon nanotube nanocomposite in As+3 toxic ions removal

Highly efficient removal of toxic As(V), Cd (II), and Pb(II) ions from water samples using MnFe2O4@SBA-15-(CH2)3-adenine as a recyclable bio-nanoadsorbent

Millions of people nowadays are exposed to highly toxic ions, including arsenic, cadmium, and lead, which all have detrimental effects on human health and cause irreparable damage to the nature and health of living species. It is, therefore, absolutely crucial to remove these toxic ions from ecosystems. Herein, a sponge-like bio-nanocomposite with a core-shell-shell structure consisting of magnetic MnFe2O4 nanoparticles (NPs) as core and mesoporous silica (SBA-15) functionalized with the nucleobase adenine (Ade) as a shell was synthesized to be applied for the adsorptive removal of toxic ions from aqueous media. The prepared material was characterized using various techniques, such as FTIR, XRD, TEM, VSM, and BET. Under optimum conditions, the MnFe2O4@SBA-15@(CH2)3-Ade removed As(V), Cd(II), and Pb(II) ions with greater than 96% efficiency. The kinetic and equilibrium data were satisfactorily described by the pseudo-second-order and the Redlich-Peterson models. The maximum adsorption capacities for As(V), Cd(II), and Pb(II) were calculated to be 21.99 mg g−1, 29.62 mg g−1, and 31.01 mg g−1, respectively. Also, the bio-nanocomposite showed ion removal efficiencies of over 95% during the seventh cycle of adsorption-desorption. Pb (II) ions had a stronger affinity for the active sites of the bio-nanoadsrobent when all of the studied systems (mono-, bi-, and multi-component) were compared. In addition, the practical application of the bio-nanocomposite for ion capture was evaluated in groundwater and industrial wastewater samples. Based on the findings of this study, the MnFe2O4@SBA-15@(CH2)3-Ade can be considered a promising adsorbent for the fast and efficient removal of heavy metals from water matrices.

Varying growth behavior of redox-sensitive nanoparticles on 1:1 and 2:1 clay surfaces: Mechanistic insights on preferential toxic ions removal in mono, co, and multi-metal contaminated waters

In the current study, contrasting growth behaviour of redox sensitive Fe0 nanoparticles (nZVI) was observed on different clay surfaces i.e., 1:1 non-swelling kaolinite (K-nZVI) and 2:1 swelling bentonite (B-nZVI). Osmotic swelling of bentonite led to Fe0 nucleation and growth of 5–7 nm size particles in the broadened interlayer spaces. B-nZVI had negative zeta potential due to the domination of the surface charge of bentonite clay. In contrast, kaolinite has shown dominant surface growth of nZVI particles (>24.8 ± 7.4 nm) and positive zeta potential, suggesting domination of Fe0 nanoparticles (nZVI) characteristics. This surface-dependent variation led to higher and faster removal of oxy-anions with K-nZVI, i.e., chromium and arsenic (87.5 and 157.35 mg/g) than B-nZVI (18.4 and 86.9 mg/g). In comparison, B-nZVI has shown higher sorption of cations i.e., nickel and cadmium (36 mg/g and 46 mg/g) than K-nZVI (25 and 27 mg/g). XPS and pXRD analysis of reaction precipitates confirmed reductive sorption of chromium, co-precipitation/ complexation of arsenic, electrostatic attraction and complexation of nickel and cadmium as major removal mechanisms. Drastically higher total contaminant sorption capacities of B-nZVI (327 mg/g) and K-nZVI (372 mg/g) in multi-contaminant (Cr + As + Ni + Cd) solutions than individual capacities in mono-ionic solutions was due to co-operative effects and newer sites induced via sorption and redox-transformation of other ionic species. K-nZVI removed chromium and arsenic to below drinking water permissible limits whereas B-nZVI succeeded in separating nickel and cadmium to drinkable levels in groundwater, freshwater, river water, and wastewater samples, emphasizing their applicability in high cationic—low anionic and low cationic-higher anionic species contaminated waters, respectively.

Rapid and efficient removal of toxic ions from water using Zr-based MOFs@PIM hierarchical porous nanofibre membranes

The development of new adsorbent materials to improve adsorption capacity and selectivity constitutes a significant research direction for removing toxic ions from water. In this study, a series of Zr-based metal–organic framework hierarchical porous nanofibre membranes (MOFs@PIM-W) was designed and successfully synthesised, and their adsorption properties and mechanism for fluoride ions in water were investigated. The formation of Zr–F bonds in Zr-based MOFs is a primary reason for the rapid, effective, and stable removal of fluoride ions from water. Moreover, in contrast to common powder adsorbents and the conventional static adsorption process, the obtained hierarchical porous nanofibre membranes improve the removal rate of fluoride ions, which may be attributed to the formation of hierarchical porous structures. Specifically, by modifying the types of MOFs, the obtained nanofibre membranes can effectively remove Hg(II) ions from water under a wide range of pH environments (pH = 2–10) with a removal rate of up to 99 %. This indicates that the hierarchical porous design of nanofibre membranes incorporated with their specific adsorption provides a viable option for rapidly and efficiently removing toxic ions from water.

Infiltration of 3D-macrocycles to integrally skinned asymmetric P84 co-polyimide membranes for boron removal

We have molecularly designed negatively charged nanofiltration (NF) membranes by chemical modification of P84 flat membranes with hyperbranched polyethylenimine (HPEI) polymers and then infiltration of sulfocalix[4]arene (SCA4) to enhance their chemical stability and molecular sieving capability. The high molecular weight HPEI polymers developed a strong cross-linked network of P84 polymer chains with extraordinary chemical stability in solvents like N-methyl-2-pyrrolidone (NMP). In addition, the amine groups of HPEI ionically bonded with the electron-accepting sulfonic acid groups of SCA4, resulting in the cross-linked membranes with a proper pore dimension and enhanced size sieving capability. The NF membrane infiltrated with SCA4 in a 0.03 wt% SCA4 solution consisting of 50/50 (wt%) water and methanol for 8 h has boron rejections of 55.37 %, 67.23 %, 87.45 %, 89.95 %, and 98.24 % at pH = 4, 7, 8, 9 and 10, respectively. These performances are comparable with or superior to literature results for membranes made from thin-film interfacial polymerization. The unique SCA4 closed-loop structure not only enhances molecular sieving capability but also achieves negatively charged NF membranes that maximize the potential for removal of toxic ions. This study may provide useful insights to design NF membranes with the aid of supramolecular macrocycles for water reuse and removal of toxic ions.

TREATMENT OF INDUSTRIAL WASTEWATER FROM CADMIUM COMPOUNDS

The article is devoted to the problem of solving an urgent environmental problem - the rational use of water resources. The most harmful and widespread toxic substances in wastewater, andin some cases in natural waters, are heavy metal compounds, in particular cadmium, which belongs to the 2nd class of hazard. The presence of a large number of metal processing enterprises, chemical, machine-building, and metallurgical enterprises with electroplating shops for applying metal coatings leads to the formation of a large amount of metal-containing wastewater, which makes the problem of wastewater treatment containing heavymetals quite relevant.Among the developed approaches, sorption methods are important, as they ensure the mostcomplete removal of toxic ions, especially from solutions with low concentrations that exceedpermissible standards. The successful development of sorption water treatment technology is based on the development of high-quality sorbents. The development of effective methods for the treatment of industrial wastewater from heavy metal ions is an urgent problem of our time. The paper presents the results of experimental studies of water purification from cadmium ions using ferromagnetic sorbents obtained from waste industrial solutions. The optimal parameters of the purification process from the dose of magnetite, pH of the medium, at different ratios of Fe2+ : Fe3+ ratio in magnetite.

Bioinspired honeycomb-like 3D architectures self-assembled from chitosan as dual-functional membrane for effective adsorption and detection of copper ion

Metal ions released through industrial and human activities are difficult to degrade in the environment, and copper (II) ingestion and accumulation in the body would cause harm to human health and even disease. The environmentally friendly materials for simultaneous detection and removal of toxic ions are urgently required to be developed. Herein, carbon dots (CDs) with excellent optical properties as crosslinking agent introduced into chitosan-based membranes with freeze casting technique. The as-synthesized fluorescent membranes (CS-CDs) could generate fluorescent response to copper (II) with adsorption capacity (12.48–49.97 mg/g). Based on the stable fluorescence signal of CS-CDs and fluorescence quenching with copper (II), a simple fluorescence spectrometry method for detection of copper (II) was established. The fluorescence intensity of CS-CD-4 decreased linearly with copper (II) concentrations ranging from 0 to 350 μmol/L. Moreover, the 3D regular honeycomb-like porous structure of CS-CDs facilitated the mass transfer and provided more effective sorption sites. The adsorption isotherm and kinetics were more suitable for the Langmuir model (R = 0.9927) and pseudo-second-order model (R = 0.9989), which indicated the adsorption were monolayer adsorption and chemisorption, respectively. As a result, the CS-CDs with dual-functionalities of detecting and adsorbing copper (II) were successfully fabricated, demonstrating the potential application prospect in environmental protection.

Enhanced stability of hydroxyapatite/sodium alginate nanocomposite for effective fluoride adsorption

Fluoride contamination is the main contributor to environmental pollution, which occurred mainly due to anthropological activity. Owing to their biocompatibility, biomaterials have been widely used as an adsorbent for the removal of toxic ions by adsorption techniques. The hydroxyapatite (HAp) and its composites of sodium alginate (HAp/SA) were synthesized by the co-precipitation method. Batch adsorption experiments were used to find adsorption capacity by varying physical parameters such as the contact time, pH, initial concentration, and co-anions . At pH 7, the maximum fluoride adsorption capacity of HAp, HAp/SA1, and HAp/SA4 was 10 mg/g, 35 mg/g, and 50 mg/g, respectively. The fluoride ion adsorption capacity was increased by 92% compared to the HAp-sodium alginate compound reported so far. The recycling efficiency of HAp/SA4 showed (96%) sustained fluoride removal for five consecutive recycles. The fluoride adsorption follows the monolayer and chemisorption mechanisms, as confirmed by the Langmuir and pseudo second-order kinetics, respectively. The higher electronegative fluoride ions can be exchanged with phosphate, carbonate, and the hydroxyl surface functional groups of adsorbent. Therefore, this result suggests that the HAp/SA composites can be used as an efficient fluoride ion absorbent in water.

Facile hydrothermal synthesis of calcium silicate nanostructures for removal of Hg(II) and Cd(II) ions from aqueous media

ABSTRACT In this work, we have synthesised a mixture consisting of sodium calcium silicate and calcium silicate nanostructures in the presence and absence of the hydrothermal method. The synthesised products were identified utilising many techniques such as XRD, EDS, FT-IR, HR-TEM, and FE-SEM. The XRD demonstrated that the mean crystallite size of the product, which was synthesised in the absence of the hydrothermal method, is 72.71 nm. The average crystallite size of the products, which were synthesised using the hydrothermal method at 160℃ for 4, 8, and 16 h, are 44.85, 34.89, and 37.38 nm, respectively. HR-TEM confirmed that all the products consist of irregular and rod shapes. The product, which was synthesised after 8 h of hydrothermal treatment, was operated as an adsorbent for the efficient removal of toxic ions (Cd(II) and Hg(II)) from aqueous media. The maximum adsorption capacity of the adsorbent towards Hg(II) and Cd(II) ions are 177.94 and 199.20 mg/g, respectively. The removal process of the studied ions was fitted well with the pseudo-second-order kinetic model and Langmuir equilibrium isotherm. Thermodynamic parameters confirmed that the removal process of the studied ions was spontaneous, chemical, and endothermic.

Fabrication of lanthanum linked trimesic acid as porous metal organic frameworks for effective nitrate and phosphate adsorption

The potable water crisis worldwide may lead to the detoxification of aquatic pollutants which becomes the research hotspot. The construction of metal-organic frameworks (MOFs) serves as the promising adsorbent material for the efficient removal of toxic ions from aqueous solution. Hence, the present research article covers the development of lanthanum linked trimesic acid (LTA) based MOFs for soluble nitrate (NO3−) and phosphate (PO43−) adsorption from water. The developed LTA MOFs were characterized by numerous instrumentation techniques like FTIR, SEM, EDAX, XRD, TGA, DTA and BET studies. The function of LTA MOFs declares the enhanced removal properties on NO3−/PO43− adsorption at batch condition. The adsorption mechanism of LTA MOFs was explored along with kinetics, isotherms and thermodynamic studies. The emerging trends of LTA MOFs for controlling the water quality parameters were also discussed at field level. The synthesized LTA MOFs could be reused many cycles for adsorption technique.

Insight into surface hydroxyl groups for environmental purification: characterizations, applications and advances

Nanomaterials-involved heterogeneous interface functionalization, including adsorption and chemical catalysis, has developed into one of the most efficient environmental purification technologies, but the reaction efficiencies are extremely limited on account of the inferior interaction between reactant and the interface of nanomaterials. Surface hydroxyl groups (SHGs) on the interface of initial nanomaterials, even in infinitesimal concentration, are confirmed to play a decisive role in determining the kinetics, energetics, and even mechanisms of interface reactions. This review endeavors to clarify the investigations of SHGs in recent years, including the important characteristics and kinds of the SHGs, and also summarize the applications of SHGs in environmental remediation, including toxic ions removal, organic wastewater degradation, harmful waste gas removal and CO2 reduction. It is beneficial to consolidate and innovate the fundamental theories of environmental catalysis by a further cognizance on SHGs' chemical behavior. And novel perspectives and indications are presented on the rational design of catalysts with satisfactory performance. [Display omitted]

Recyclable aptamer-derived aqueous two-phase flotation for high-efficiency separation of mercury(II) ions modulated by aggregation states

• An efficient and economical ATPF technology was applied to Hg(II) ions removal. • ATPF separation of 97.22% of Hg(II) ions was achieved using TBC-P as a collector. • Hg(II) was captured onto TBC-P via specific coordination between Hg(II) and imide. • Recycling of collector and polymer was possible with removal of 70% Hg(II) ions. Developing an efficient and economical strategy for selective removal of toxic ions drives exploration of separation technology. In this respect, aqueous two-phase flotation (ATPF) is a promising technology, but for practical separation, it is restricted by low selectivity and difficult recycling of collector. Herein, we constructed aptamer-derived ATPF that could address these fundamental limitations by using aptamer-functionalized thermo-responsive polymers as collectors. Collector, PEG 113 -b-P(NIPAM 90 -co-HBMA 3 )-P (TBC-P), was relied on specific and reversible coordination interactions between aptamers and Hg(II) ions, and simple separation by thermally precipitating, achieving the highly efficient separation of Hg(II) ions and recycling of collector. Single-factor experiments were carried out first to determine the critical variables in influencing the removal of Hg(II) ions. Response surface methodology (RSM) was further conducted to optimize the removal conditions. Statistical analysis indicated that the quadratic models was significant, and could be utilized to determine optimum process conditions. Under the optimum process conditions, separation efficiency and partition coefficient for Hg(II) ions displayed by ATPF were 97.22% and 3.47, respectively. The collectors and phase-forming components were easily recovered, and then recycled to maintain 70% of its initial separation efficiency and 50% of its initial partition coefficient in the fifth cycle. This satisfactory result verifies aptamer-derived ATPF is a feasible and practical method, providing a great guarantee for pollutant treatment to ensure sustainable environment.

Salinity induced alterations in photosynthetic and oxidative regulation are ameliorated as a function of salt secretion.

Ion secretion facilitates recretohalophytes to tolerate saline and drought conditions but its relative contribution to the survival of many species remains poorly understood. Tamarix chinensis has high potential for restoration of saline deteriorated lands. The water management and high salt tolerance of the plant have highlighted the need to determine the strategies that govern these mechanisms. Here we report the selectivity of this halophyte to transport, utilize, and secrete different cations and anions under various NaCl (0, 100, 200 and 400mM) concentrations. Plant growth, photosynthesis and antioxidant defense responses were also determined to relate them with the function of ion secretion. Results reflected two different sets of strategies adopted by plants to survive low and high salinities. Exposure to highly saline conditions caused reduction in photosynthesis due to stomatal and biochemical limitations. The decreased content of photosynthetic pigments exposed plants to excessive light energy that accelerated production of ROS (i.e., hydrogen peroxide H2O2) and caused damage to cellular membranes. The increased activities of anti-oxidative enzymes (superoxide-dismutase, catalase, ascorbate-peroxidase, and glutathione-reductase) were insufficient to detoxify H2O2. In contrast, plants treated with low salinity did not face stomatal limitations while the photosynthetic pigments increased. As no damage to membranes was detected, the increased content of H2O2 was postulated for its messenger role. The assimilation of essential nutrients was affected due to increased content of toxic ions (Na+ and Cl-) in the growing medium and within the plants. However, the ability to regulate K+ facilitated plants to improve water use efficiency under hyper-osmotic environment. The removal of toxic ions from the photosynthesizing tissues demands high energy, which was evident in the compromised growth of plants. This study offers a window to physiological mechanisms, e.g., potassium retention that ensure salt secretion as a beneficial strategy for prolonged survival of T. chinensis.

Selective Removal of Toxic Ions from Water/Wastewater: Using a Novel Surfactant

Pollution of drinking water by toxic heavy-metal ions is a matter of concern worldwide. These ions occur naturally, and also from environmental spills, radioactive wastes and other industrial waste. Arsenic and lead are typical examples. A novel green surfactant, purpose designed, and environmentally friendly is shown to be extremely effective and specific for heavy metal ion removal. This is a considerable step forward on previous technologies. Surfactants have been used universally to remove organic and inorganic contaminants from water. But little selectivity has been achieved. After usage, the residual surfactants are discharged into surface waters or sewage systems. This causes environmental pollution. In this review, three surfactants from different classes (novel green surfactant, synthetic chemical surfactant and biosurfactant) are compared in terms of their efficiency in flotation, removal of different heavy-metal ions, biodegradability, and toxicity level, including their advantages and disadvantages.

Carbonated nanohydroxyapatite from bone waste and its potential as a super adsorbent for removal of toxic ions

The effective, low-cost decontamination of toxic metals is critical for addressing global health risks, reducing environmental pollution, and building a sustainable future. Here, we developed an eco-friendly hydroxyapatite nanocrystal adsorbent made from bone waste that can effectively capture 90Sr. Highly carbonated nanohydroxyapatite (C-NHAP) crystals with a negatively charged surface were obtained by simply immersing pig bone in an aqueous solution of sodium hydrogen carbonate (NaHCO3). Fourier transform infrared spectra showed that the C-NHAP was highly carbonated and that the amount of introduced carbonate ions (CO32−) increased with increasing NaHCO3 concentration in the immersion solution. With increasing amount of CO32− ions introduced into the C-NHAP, it exhibited a greater ion-adsorption performance. The distribution coefficient (Kd=24,780 mL g−1) of the C-NHAP for Sr2+ was approximately 20 and 250 times greater than those of clinoptilolite and untreated bone, respectively. The C-NHAP also exhibited high adsorption capacity (Qe=125 mg g−1) for Sr2+. The extended X-ray absorption fine structure spectra showed that the CO32− sites in C-NHAP played an important role in its high adsorption performance. The C-NHAP exhibited high adsorptivity for Cd2+, Pb2+, and Cu2+. The C-NHAP prepared from bone waste is an eco-friendly, high-performance, low-cost material that should be useful in environmental pollutant removal and food waste disposal.

Magnesium ferrite-reinforced polypyrrole hybrids as an effective adsorbent for the removal of toxic ions from aqueous solutions: Preparation, characterization, and adsorption experiments

Contaminated waters with high contents of toxic anions are detrimental to the human health and wildlife. Thus, the quality of drinking water should be carefully monitored. Adsorption technique has been determined to be a reasonable strategy out of several methods used to remove toxic anions from water. Novel MgFe2O4-reinforced polypyrrole (Ppy@x%MgFe2O4) (x = 1%, 2%, and 5% of MgFe2O4) hybrids were synthesized from a pyrrole monomer and MgFe2O4 using a simple chemical oxidation method. The fabricated hybrids were studied for their capability to remove PO43–, NO3–, and Cr(VI) from aqueous solutions. The results showed that PO43–, NO3–, and Cr(VI) removal was highly pH-dependent. The adsorption isotherms of hybrids were fitted well by the Langmuir model, with the maximum adsorption efficiency of 116.90, 76.14, and 138.60 mg/g for PO43–, NO3–, and Cr(VI), respectively. In addition, the above-mentioned toxic anions could be efficiently desorbed from spent Ppy@x%MgFe2O4 using a 0.1 M NaOH solution, and the hybrids exhibited good regenerability. The prepared materials are promising candidates for PO43–, NO3–, and Cr(VI) removal and exhibit high adsorption efficiency, rapid adsorption–desorption behavior, and appropriate recovery from the aqueous medium under external magnetic field.