Adsorption Of Toxic Metals Research Articles

Chemical modifications on pinus bark for adsorption of toxic metals

Current research produced modified adsorbents from pinus bark with high removal capacity of Cd(II), Pb(II) and Cr(III) from water. Pinus barks were obtained directly from pinus logs and its biomass was chemically modified by solutions of H2O2, H2SO4 and NaOH 0.1 mol L−1. The adsorbents were characterized by means of their chemical composition, their point of zero charge (pHPZC), FT-IR, SEM, porosity and superficial area. Experiments evaluated the effect of contact time and equilibrium. Best results showed an increase in adsorption capacity for Cd, Pb and Cr of 413 (Qm of Langmuir), 259 (Qm of Langmuir) and 207% (Kf of Freundlich) for P. NaOH, P. NaOH and P. H2SO4, respectively. The modifying solutions were effective, and chemically modified the pinus bark, increasing the removal quantity of metals from water.

A magnetic nanocomposite produced from camel bones for an efficient adsorption of toxic metals from water

Abstract A new, simple, clean, and green procedure for the production of a magnetic nanocomposite (MBBC) from waste camel bone biochar was here described. MBBC particles were in the nano-size range (∼12 nm), having characteristics of both hydroxyapatite and magnetite. The produced nanocomposite was characterized by FT-IR, XRD, TG, SEM, TEM, BET, XRD, Zeta potential and XPS analyses. MBBC exhibited a paramagnetic behavior, having a saturation magnetization of 50.20 emu/g and a mesoporous structure with a BET surface area of 162 m2/g. The FT-IR spectrum of MBBC displayed doublet peaks at 573–601 cm−1 (corresponding to Fe–O vibrations) and a peak at 1046 cm−1 (associated with HPO4), which support the successful formation of MBBC. The maximum adsorption capacities of MBBC, as for the Langmuir isotherm model fittings, were 344.8, 322.6 and 294.1 mg/g for Pb(II), Cd(II) and Co(II), respectively. MBBC showed rapid heavy metals adsorption rates, accomplishing ∼75% adsorption within 5 min. After adsorption accomplishment, MBBC particles were magnetically separated from treated water and heavy metals from saturated MBBC were efficiently desorbed by elution with 0.01 M HCl. Under such elution, the MBBC stability against acid leaching of Fe was proved. Hence, it could be inferred that the production of MBBC from waste camel bones and its utilization for the removal of heavy metals from water is a novel approach within the cleaner production concept.

A review of the application of agricultural wastes as precursor materials for the adsorption of per- and polyfluoroalkyl substances: A focus on current approaches and methodologies

Abstract There is an abundant body of literature surrounding the use of agricultural wastes for the adsorption of pollutants from aqueous solutions. This area of research is often considered as an alternative to conventional treatment techniques. In the past, the research focus centred on the adsorption of toxic metals. Presently, there is an increase in the calls, for researchers to explore new adsorbent materials for the removal of organic pollutants. Since once ingested, these organic pollutants have health impacts such as chronic kidney and liver diseases and endocrine disruption. Hence, there is an increasing need to discover new and efficient ways of removing organic pollutants from water systems. It is worth mentioning that most agricultural wastes are not usually utilized in their original state, but rather modified in diverse ways to increase the material’s surface area of adsorption and porosity. Thermal treatment, carbonization, chemical and physical activation, nanostructuring, grafting with copolymers and many others are some of the widely used methodologies; that are currently being employed for modifying agricultural waste materials for use as adsorbents. In this review, therefore, a discourse on a range of agricultural wastes that have been used as adsorbents for the removal of per- and polyfluoroalkyl substances (PFAS) from aqueous media is provided. A proposition of the use of maize tassel–silver nanoparticles as new comers is made. This review article serves to give key insights on the technical realizations in the area of adsorption of PFAS by utilizing agricultural wastes as precursor materials for preparing adsorbents.

One-pot synthesis of trifunctional chitosan-EDTA-\u03b2-cyclodextrin polymer for simultaneous removal of metals and organic micropollutants

The global contamination of water resources with inorganic and organic micropollutants, such as metals and pharmaceuticals, poses a critical threat to the environment and human health. Herein, we report on a bio-derived chitosan-EDTA-β-cyclodextrin (CS-ED-CD) trifunctional adsorbent fabricated via a facile and green one-pot synthesis method using EDTA as a cross-linker, for the adsorption of toxic metals and organic micropollutants from wastewater. In this system, chitosan chain is considered as the backbone, and the immobilized cyclodextrin cavities capture the organic compounds via host-guest inclusion complexation, while EDTA-groups complex metals. The thoroughly characterized CS-ED-CD was employed for batch adsorption experiments. The adsorbent displayed a monolayer adsorption capacity of 0.803, 1.258 mmol g−1 for Pb(II) and Cd(II) respectively, while a heterogeneous sorption capacity of 0.177, 0.142, 0.203, 0.149 mmol g−1 for bisphenol-S, ciprofloxacin, procaine, and imipramine, respectively. The adsorption mechanism was verified by FT-IR and elemental mapping. Importantly, the adsorbent perform is effective in the simultaneous removal of metals and organic pollutants at environmentally relevant concentrations. All these findings demonstrate the promise of CS-ED-CD for practical applications in the treatment of micropollutants. This work adds a new insight to design and preparation of efficient trifunctional adsorbents from sustainable materials for water purification.

Novel chelant‐based washing method for soil contaminated with Pb and other metals: A pilot‐scale study

AbstractRemediation with chelants can restore metal‐contaminated soils for use as a natural resource. Calcareous soil from Meza Valley, Slovenia, and acidic soils from Arnoldstein, Austria, and Pribram, Czech Republic (with 1,028, 862, and 926 mg ∙Pb∙kg−1, respectively), were washed with 60–100 mmol EDTA per kilogram of air‐dried soil in series of 30 batches (50 kg soil batch−1). The approach involves a novel reaction that incorporates alkaline substitution, precipitation and adsorption of toxic metals on polysaccharides, and chelant acidic precipitation via 83% EDTA (on average) and complete process water recycling (no wastewater was generated). The pH gradient was imposed by Ca(OH)2 and H2SO4, and excess reagent was removed with the remediated soil as CaSO4, thereby preventing the salification of the recycled waters. Remediation removed 60%, 78%, and 71% of the Pb from the Meza, Arnoldstein, and Pribram soils, respectively, and reduced the Pb bioaccessibility levels in the simulated human gastrointestinal phase by 5.0, 7.7, and 8.1 times. Residual emissions (EDTA, toxic metals) were reduced with soil aging and remediated soil deposition on a reactive permeable barrier. The solid waste generated from the process totaled 10.8 kg tons−1 of the air‐dried soil, and the material/energy costs of remediation reached 20.6 € tons−1. These results demonstrate the robustness, efficiency, and safety of this novel approach.

Fractal-like concepts for evaluation of toxic metals adsorption efficiency of feldspar-biomass composites

Effective treatment of metals polluted water may be achieved using low-cost materials synergistically modified to obtain composite adsorbents. Thus, feldspar–biomass composites have been prepared via calcination of feldspar (FLC) and Carica papaya seeds or pine cone seeds to yield Carica papaya-FLC (CPF) and pine-cone-FLC (PCF) composite adsorbents, respectively. The composites physicochemical properties and effectiveness for Pb(II), Cd(II) and Cu(II) removal in aqueous solutions were examined. Results showed that calcination did not promote any structural modification in the basic FLC lattice. Though CPF and PCF exhibited lower specific surface area when compared with the FLC, their cation exchange capacities were enhanced. Unlike on the FLC, the metals adsorption on CPF and PCF were higher (>40%) for Cu(II) and Cd(II), pH independent and faster. The study showed that adsorption process on a system with varying types of surface sites and with varying affinity for an adsorbent can best be described by the fractal-like kinetic and equilibrium adsorption isotherm models (fractal pseudo-second order kinetic model and fractal Brouers–Sotolongo adsorption model) compared with the classical models (pseudo-first order and pseudo-second order kinetic models, Langmuir and Freundlich adsorption isotherm models). These adsorption processes were thermodynamically spontaneous, feasible and endothermic; however the modification significantly reduced their energy requirements. The Brouers–Sotolongo model showed that modification of FLC increased the width of the sorption energy distribution on the composites indicating the heterogeneity of the surface adsorption sites. Though no single classical theory of sorption can presently be put forward to explain the overall adsorptive process, metals adsorption on these feldspar-biomass composites are heterogeneous and complex processes with fractal architecture.

Fulvic acid anchored layered double hydroxides: A multifunctional composite adsorbent for the removal of anionic dye and toxic metal

A novel multifunctional composite adsorbent which possesses the ability for anion exchange and toxic metal complexation has been synthesized by the hybridization of layered double hydroxides (LDH) and fulvic acid (FA) in this study. The results show that FA with lots of functional groups can be effectively and stably anchored on the surface of LDH through coagulation process without occupying the interlayer of LDH. Therefore, the anion exchange ability remains and the adsorption capacity of Orange II can reach 1.9mmol/g, which is almost as much as stoichiometric anion exchange capacity of pure LDH. Moreover, the composite adsorbent’s adsorption capacity of Cu2+, Pb2+, Ni2+ and Cd2+ can also get to 2.25mmol/g, 0.98mmol/g, 0.99mmol/g and 0.16mmol/g respectively with an adsorption preference order of Cu2+>Pb2+>Ni2+>Cd2+. In addition, Orange II and toxic metals are able to be simultaneously removed by this composite adsorbent, and the adsorption of toxic metals can be enhanced by the synergetic adsorption of Orange II. Anion exchange with Cl− in LDH matrix accounts for the adsorption of Orange II, while the adsorption of toxic metal is mainly attributed to the complexation of carboxyl functional group derived from FA.

Is Male Rheumatoid Arthritis an Occupational Disease? A Review.

Background:Rheumatoid arthritis (RA) is a systemic, inflammatory disease with an estimated global prevalence of 0.3–1.0%. An unexplained association exists between low formal education and the development of RA independent of smoking. It is established that RA is initiated in the lungs and that various occupations associated with dust, fume and metal inhalation can increase the risk of RA development.Objective:The objective of this review is to evaluate published clinical reports related to occupations associated with RA development. We highlight the concept of a “double-hit” phenomenon involving adsorption of toxic metals from cigarette smoke by dust residing in the lung as a result of various work exposures. We discuss the relevant pathophysiological consequences of these inhalational exposures in relation to RA associated autoantibody production.Method:A thorough literature search was performed using available databases including Pubmed, Embase, and Cochrane database to cover all relative reports, using combinations of keywords: rheumatoid arthritis, rheumatoid factor, anti-citrullinated peptide antibody silica, dust, fumes, metals, cadmium, cigarette smoking, asbestos, mining, bronchial associated lymphoid tissue, heat shock protein 70, and adsorption.Conclusion:We postulate that the inhalation of dust, metals and fumes is a significant trigger factor for RA development in male patients and that male RA should be considered an occupational disease. To the best of our knowledge, this is the first review of occupations as a risk factor for RA in relation to the potential underlying pathophysiology.

Effects of adhesions of amorphous Fe and Al hydroxides on surface charge and adsorption of K+ and Cd2+ on rice roots

Iron (Fe) and aluminum (Al) hydroxides in variable charge soils attached to rice roots may affect surface-charge properties and subsequently the adsorption and uptake of nutrients and toxic metals by the roots. Adhesion of amorphous Fe and Al hydroxides onto rice roots and their effects on zeta potential of roots and adsorption of potassium (K+) and cadmium (Cd2+) by roots were investigated. Rice roots adsorbed more Al hydroxide than Fe hydroxide because of the greater positive charge on Al hydroxide. Adhesion of Fe and Al hydroxides decreased the negative charge on rice roots, and a greater effect of the Al hydroxide. Consequently, adhesion of Fe and Al hydroxides reduced the K+ and Cd2+ adsorption by rice roots. The results of attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and desorption of K+ and Cd2+ from rice roots indicated that physical masking by Fe and Al hydroxides and diffuse-layer overlapping between the positively-charged hydroxides and negatively-charged roots were responsible for the reduction of negative charge on roots induced by adhesion of the hydroxides. Therefore, the interaction between Fe and Al hydroxides and rice roots reduced negative charge on roots and thus inhibited their adsorption of nutrient and toxic cations.

A Potential Bio-Sorbent for Heavy Metals in the Remediation of Waste Water

Bay leaves are used for flavoring in cold drinks production, in bakery goods, sauces, confectionary products and liquors. The waste generated from these sources has been valorized by attempting the remediation of waste water. Hence, adsorption of toxic metals onto Bay leaves has been investigated after optimizing the experimental parameters, namely the pH, contact time, adsorbent and Zn(II) concentrations as well as the temperature of the equilibrium mixture (consisting of the metal solution in contact with the adsorbent). The participation of the constituent functional groups, of the adsorbent, was ascertained with Fourier transform spectroscopic studies. The mode of adsorption was examined by employing important isotherm models, namely Langmuir, Freundlich and Dubinin-Radushkevich models. The adsorption process was found to follow pseudo-first order kinetic model and also followed the intraparticle diffusion up to 60 minutes of contact time. The thermodynamic parameters suggest the spontaneous nature of adsorption.

Competitive adsorption of toxic metals on bentonite and use of chitosan as flocculent coagulant to speed up the settling of generated clay suspensions

Evaluation of modified Algerian clay as mineral adsorbent was done for its adsorbing capacity on copper (Cu) and Zinc (Zn) cations. The results obtained show a rapid kinetic adsorption for both metals (less than 2 h) following the pseudo-second order model with high elimination rates of 67.2 and 61.8% for Cu and Zn respectively. The adsorption isotherms analyzed with Langmuir model revealed a correlation with the experimental values. While the use of obtained chitosan at room temperature, as flocculent coagulant, accelerates the decantation of the colloidal particles in suspension generated after adsorption process.

Impact of Humin on Soil Adsorption and Remediation of Cd(II), Pb(II), and Cu(II)

ABSTRACTIn situ immobilization constitutes a promising technology for the mitigation of contaminants, through the reduction of metal bioavailability and mobility. This study investigated the adsorption isotherms and kinetic characteristics of humin extracted from peat soils. We also studied the influences of the pH, ionic strengths, and soluble organic matter concentrations of soil solutions on the adsorptive properties of humin, and compared its ability to detoxify potentially toxic metals in both actual and simulated soil solutions. The study results indicated that humin contains a massive population of oxygen-containing functional groups. Its adsorption capacity for Pb(II) was greater than that for Cu(II), which exceeded that for Cd(II). The adsorption of humin for Pb(II) conformed to the Freundlich model, while the adsorption of humin for Cd(II) and Cu(II) followed the Langmuir model. The adsorption kinetics of humin with respect to potentially toxic metals aligned well with second-order kinetics equations. As the pH was elevated, the potentially toxic metal adsorption by humin increased rapidly. Electrolyte ions and tartaric acids in solution both inhibited the adsorption of potentially toxic metals by humin, and its ability to inactivate potentially toxic metals. This was shown to be improved in actual field soil solutions in contrast to simulated soil solutions.

Adsorption of Toxic Metals and Control of Mosquitos-borne Disease by Lysinibacillus sphaericus: Dual Benefits for Health and Environment

ObjectiveAssessment of the bacterium L. sphaericus as a dual-action candidate for biological control of mosquito-borne diseases and bioremediation of toxic metals. MethodsLarvae of the mosquito, C. quinquefasciatus, were first evaluated for metal tolerance and then exposed to 5 ppm cadmium, chromium, arsenic, and lead in assays together with seven strains of L. sphaericus. A probit regression analysis was used to estimate the LC50 of Cd, Cr, As, and Pb to C. quinquefasciatus. An analysis of covariance and multifactorial ANOVA examined the metal biosorption and larvicidal properties of the seven strains of L. sphaericus. ResultsWe found that L. sphaericus adsorbed the toxic metal ions and was toxic against mosquito larvae. The L. sphaericus strain III(3)7 resulted in a larvae mortality of over 80% for all the tested metals. This strain also exhibited the capacity to adsorb 76% of arsenic, 32% of lead, 25% of chromium, and 7% of cadmium. ConclusionThis study found combined metal adsorption and larval toxicity associated with three strains of L. sphaericus [III(3)7, OT4b.31, and CBAM5]. This suggests that a combination of these strains shows strong dual potential for biological control of mosquitos in heavy metal-contaminated areas and remediate the heavy metal contamination as well.

Facile fabrication of silk protein sericin-mediated hierarchical hydroxyapatite-based bio-hybrid architectures: excellent adsorption of toxic heavy metals and hazardous dye from wastewater

Facilely fabricated silk protein sericin-mediated hierarchical hydroxyapatite hybrid architectures show excellent adsorption of toxic heavy metal ions of Pb(ii), Cd(ii) and Hg(ii) and a hazardous dye, Congo red (CR), from wastewater.

Toxic metal biosorption by macrocolonies of cyanobacterium Nostoc sphaeroides Kützing

The cyanobacterium Nostoc sphaeroides Kutzing is expected to be effective in toxic metal adsorption as it produces abundant exopolysaccharides with functional groups. Therefore, the adsorption properties of Cu2+, Cd2+, Cr3+, Pb2+, Ni2+, and Mn2+ on fresh macrocolonies and algal powder of N. sphaeroides were compared at pH 5 and 25 °C. The adsorption capacity of fresh biomass for Pb2+ and of algal powder for Pb2+ and Cr3+ were highest in single metal solutions. Compared to the fresh biomass, the metal adsorption capacities of algal powder were similar for Ni2+, Cd2+, and Pb2+ and slightly greater for Cr3+, but they were markedly smaller for Mn2+ and Cu2+. Coexisting ions (in tap water or in multiple solutions) significantly decreased the metal adsorption capacity, except for Cr3+ in tap water. The Pb2+ and Cr3+ adsorption dynamic process fitted the pseudo-second-order model well, showing fast adsorption at the first stage in 10 and 20 min, respectively. Higher pH in acidic ranges favored the adsorption greatly. The Langmuir isotherm model was suitable for explaining the adsorption, and the maximum adsorption capacities were 116.28 and 22.37 mg g−1 for Pb2+ and Cr3+, respectively. The adsorption process was endothermic, confirmed by the significantly higher adsorption capability at higher temperature. Hydroxyl, amino, and carboxyl groups were the main functional groups based on Fourier transform infrared spectroscopy analysis, and they bind to metal ions via ion exchange. The results suggest that fresh macrocolonies of N. sphaeroides can be used as an effective biosorbent for metal ion removal, especially for Pb2+ and Cr3+.

Adsorption of Cd, Cu and Zn from aqueous solutions onto ferronickel slag under different potentially toxic metal combination.

Adsorption characteristics of potentially toxic metals in single- and multi-metal forms onto ferronickel slag were evaluated. Competitive sorption of metals by ferronickel slag has never been reported previously. The maximum adsorption capacities of toxic metals on ferronickel were in the order of Cd (10.2 mg g(-1)) > Cu (8.4 mg g(-1)) > Zn (4.4 mg g(-1)) in the single-metal adsorption isotherm and Cu (6.1 mg g(-1)) >> Cd (2.3 mg g(-1)) > Zn (0.3 mg g(-1)) in the multi-metal adsorption isotherm. In comparison with single-metal adsorption isotherm, the reduction rates of maximum toxic metal adsorption capacity in the multi-metal adsorption isotherm were in the following order of Zn (93%) > Cd (78%) >> Cu (27%). The Freundlich isotherm provides a slightly better fit than the Langmuir isotherm equation using ferronickel slag for potentially toxic metal adsorption. Multi-metal adsorption behaviors differed from single-metal adsorption due to competition, based on data obtained from Freundlich and Langmuir adsorption models and three-dimensional simulation. Especially, Cd and Zn were easily exchanged and substituted by Cu during multi-metal adsorption. Further competitive adsorption studies are necessary in order to accurately estimate adsorption capacity of ferronickel slag for potentially toxic metals in natural environments.

Practical Homemade Copper Filter by Banana Peels, Sand and Charcoal for Wastewater Treatment

Copper ions are commonly contaminated in the effluents from many electronic factory. In copper filtration, most filter types are usually expensive and causes toxic residues and creates another health and environmental problem. Therefore, this research has been developed a copper filtration approach based on homemade non-hazardous residues of banana peels, unmeshed sand, and charcoal. The results showed that baked, minced banana peels media could absorb synthetic water having copper ion at 50 ppm with filtration efficiency of 70% within 2 hr. Baked minced banana peels in combination with sand and charcoal could adsorb Copper (II) at 50 mg/ mL more than 80%. However, the swollen structure of banana peels during copper (II) filtration caused limit filtration efficiency to 4-5 hour extraction period. The tentative wastewater treatment application is, therefore, the use of bio-adsorbent for effective adsorption of toxic heavy metals from effluents open discarded from agricultural wastes in the environment.

Design and Pilot Scale Application of a New Geocomposite for Capping of Contaminated Soil

This paper presents a pilot scale application of a new type Geosynthetic Clay Composite for environmental applications in the treatment of toxic metals contaminated land. The designed new geocomposite was consisted of a thin layer of permeable, attapulgite clay sandwiched between two geotextiles. To demonstrate its effectiveness a pilot scale application was implemented at a public primary school in Lavrion Greece, an area affected by extensive heavy metal soil pollution due to past metallurgical activities. The attapulgite clay in the geocomposite is an effective binder for the sorption/ adsorption of toxic metals, preventing upwards migration of metals from the contaminated subsoil to the top soil during evaporation. Also the used geotextiles ensured encapsulation but allowed downwards water infiltration. An extensive investigation of the physical and mechanical properties of this geocomposite was performed by testing both short and long-term behavior in this specific application. Environmental monitoring results over a three semester period indicated the long-term effectiveness of the applied remediation technique for toxic metal retention. Keywords: Attapulgite clay, capping, contaminated land, geosynthetics, pilot-scale, remediation, stabilization, toxic metals.

Biomineralized multifunctional magnetite/carbon microspheres for applications in Li-ion batteries and water treatment.

Advanced functional materials incorporating well-defined multiscale architectures are a key focus for multiple nanotechnological applications. However, strategies for developing such materials, including nanostructuring, nano-/microcombination, hybridization, and so on, are still being developed. Here, we report a facile, scalable biomineralization process in which Micrococcus lylae bacteria are used as soft templates to synthesize 3D hierarchically structured magnetite (Fe3O4) microspheres for use as Li-ion battery anode materials and in water treatment applications. Self-assembled Fe3O4 microspheres with flower-like morphologies are systematically fabricated from biomineralized 2D FeO(OH) nanoflakes at room temperature and are subsequently subjected to post-annealing at 400 °C. In particular, because of their mesoporous properties with a hollow interior and the improved electrical conductivity resulting from the carbonized bacterial templates, the Fe3 O4 microspheres obtained by calcining the FeO(OH) in Ar exhibit enhanced cycle stability and rate capability as Li-ion battery anodes, as well as superior adsorption of organic pollutants and toxic heavy metals.

Characterization of Toxic Metals Adsorption Isotherms on Activated Carbon Using Locally Design Jar Test Apparatus

Characterization of Toxic Metals Adsorption Isotherms on Activated Carbon Using Locally Design Jar Test Apparatus