Single Metal Solutions Research Articles

Single and binary adsorption of heavy metals on fly ash samples from aqueous solution

Thousands of toxins are released every day into the environment through numerous industrial operations and this resulted in continuous search for newer adsorbents. Two types of adsorbents, 1:10 fly ash and 1:15 fly ash samples were prepared from coal fired thermal power plant fly ash by treating it with calculated amount of calcium carbonate and phosphoric acid. Adsorbents were characterized on the basis of FTIR, XRF, surface area, pH and particle size studies. Adsorption of Pb(II), Ni(II) and Cr(VI) from single metal solutions on 1:10 fly ash from aqueous solution was carried out as a function of initial metal ion concentration, adsorbent dose, contact time and pH of the solution. Adsorption data obtained was analyzed with Langmuir, Freundlich and Temkin adsorption isotherm equations. Binary adsorption of Pb(II) and Ni(II) was studied on 1:10 and 1:15 fly ash samples as a function of initial metal ion concentration to investigate their efficiencies in removing metal ions from aqueous solution. In the case of 1:10 and 1:15 fly ash samples, Pb(II) and Ni(II) removal was observed to be almost the same. The significant difference observed between single and binary metal adsorption is in the initial metal removal rate. Slightly lower initial metal removal rate observed in the case of binary adsorption is probably due to the presence of competing metal ions in the solution. Fly ash based adsorbents prepared in the laboratory exhibited comparatively more adsorption capacity than that of the parent material, fly ash. Further, used adsorbents can be disposed in the form of concrete blocks as leaching of toxic metals is almost nil both under mild acidic and basic conditions. As cost involved in developing adsorbents from fly ash is comparatively less than other commercial adsorbents, reactivation or regeneration of used adsorbents was not considered.

Optimization of Preparation of Activated Carbon from Ricinus communis Leaves by Microwave‐Assisted Zinc Chloride Chemical Activation: Competitive Adsorption of Ni2+ Ions from Aqueous Solution

The preparation of activated carbon (AC) from Ricinus communis leaves was investigated in this paper. Orthogonal array experimental design method was used to optimize the preparation of AC using microwave assisted zinc chloride. Optimized parameters were radiation power of 100 W, radiation time of 8 min, concentration of zinc chloride of 30% by volume, and impregnation time of 24 h, respectively. The surface characteristics of the AC prepared under optimized conditions were examined by pHZPC, SEM‐EDAX, XRD, and FTIR. Competitive adsorption of Ni2+ ions on Ricinus communis leaves by microwave assisted zinc chloride chemical activation (ZLRC) present in binary and ternary mixture was compared with the single metal solution. The effects of the presence of one metal ion on the adsorption of the other metal ion were investigated. The experimental results indicated that the uptake capacity of one metal ion was reduced by the presence of the other metal ion. The extent of adsorption capacity of the binary and ternary metal ions tested on ZLRC was low (48–69%) as compared to single metal ions. Comparisons with the biosorption of Ni2+ ions by the biomass of ZLRC in the binary (48.98–68.41%‐~Ni‐Cu and 69.76–66.29%‐~Ni‐Cr) and ternary solution (67.32–57.07%‐~Ni–Cu and Cr) could lead to the conclusion that biosorption of Ni2+ ions was reduced by the influence of Cu2+ and Cr3+ ions. The equilibrium data of the adsorption was well fitted to the Langmuir isotherm. The adsorption process follows the pseudo‐second‐order kinetic model.

Bioremediation of toxic metals mercury and cesium using three types of biosorbent: bacterial exopolymer, gall nut, and oak fruit particles

Cesium and mercury are two mono-valent elements which can be found in toxic industrial, medical, and nuclear wastes. Their presence in the environment has deleterious effects on the ecosystem, living organisms including humans. Due to the chemical nature of these metals, bioremediation by conventional methods is more difficult to achieve compared to other metals. In this study, we used three biosorbents (oak powder, gall nut, and bacterial exopolymer) for the bioremediation of Hg and Cs. Bio-polymer was produced in the GMS mineral broth. Synthetic wastes of Hg(NO3)2 and isotope Cs-133 as the single-metal solutions were used. The biorefining process was carried out in glass columns, made of Pyrex, with dimensions 20 × 7/2 cm2 with a V-shaped bottom. The samples were analyzed using atomic absorption. The experimental results showed that eliminated metal percent by oak powder, gall nut, and bacterial exopolymer were, respectively, of 94.8%, 96%, and 13.8% for Hg and 7.8%, 4.4%, and 69.4% for Cs. The tests revealed that Ca++, when used as flocculant, played a key role in both biosorption and bio-precipitation rates. Consequently, it was concluded that the investigated biosorbents could be use as an integrated biosorption system for the refinement of mixed wastes.

Methods of using carbon nanotubes as filter media to remove aqueous heavy metals

Although carbon nanotubes (CNTs) are well known to have a strong affinity to various heavy metals in aqueous solution, little research has been dedicated to exploit their use in fixed-bed water treatment systems (e.g., trickling filters). In this work, batch sorption and fixed-bed experiments were conducted to examine the ability of functionalized multi-walled CNTs as filter media to remove two heavy metal ions (Pb2+ and Cu2+) from infiltrating water. Batch sorption experiments confirmed the strong sorption affinity of the CNTs for Pb2+ and Cu2+ in both single and dual metal solution systems. In addition, sonication-promoted dispersion of the CNT particles enhanced their heavy metal sorption capacity by 23.9–32.2%. For column experiments, laboratory-scale fixed-bed columns were packed with CNTs and natural quartz sand by three different packing: layered, mixed, and deposited. While all the three packing methods enhanced the fixed-bed filtering efficiency of Pb2+ and Cu2+ from single and dual metal systems, the CNT-deposited packing method was superior. Although the amount of the CNTs added into the fixed-bed columns was only 0.006% (w/w) of the sand, they significantly improved the fixed-bed’s filtering efficiency of Pb2+ and Cu2+ by 55–75% and 31–57%, respectively. Findings from this study demonstrate that functionalized multi-walled CNTs, together with natural sand, can be used to effectively and safely remove heavy metals from water.

Uptake of hazardous heavy metal ions by aqueous solution of poly(acrylamide) prepared through atom transfer radical polymerization process

AbstractPoly(acrylamide) (PACM) used in this study was prepared through an effective atom transfer radical polymerization process and characterized by NMR, FTIR, and thermo gravimetric analysis. Resulting polymer was used for the uptake of heavy metal ions from aqueous solution. Partition coefficient, retention capacity, and metal ion uptake behavior in aqueous solution of PACM at different monomer percent conversions and effect of parameters for optimization of polymerization reaction gives thermally stable PACM. Efficiency of metal ion uptake of different molecular weights of PACM were tested in batches for Ni2+, Pb2+, Cu2+, Zn2+, and Hg2+ ions in single metal solution. Metal ion sorption capacities increase with increase in polymer concentration. Metal ion sorption capacities in single metal system were 6.3 mg g−1 Ni2+, 6.0 mg g−1 Pb2+, 6.9 mg g−1 Cu2+, 6.2 mg g−1 Zn2+, 22.4 mg g−1 Hg2+ for PACM of 88% conversion (Mn = 19,850). Uptake by the PACM indicates that they are effective in removing metal ions from single metal ion solutions. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Phytoremediation of heavy metals from aqueous solutions by two aquatic macrophytes, Ceratophyllum demersum and Lemna gibba L.

Wetland plants are being used successfully for the phytoremediation of trace elements in natural and constructed wetlands. Under the present investigation, two aquatic macrophytes, Ceratophyllum demersum and Lemna gibba, were tested for their effectiveness at removing two toxic metals (Pb and Cr). These plants were grown at four different concentrations in single-metal solutions of the two metals and were separately harvested after 2, 4, 6, 9 and 12 days in a laboratory experiment. These plants performed extremely well at removing the chromium and lead from their solutions and were capable of removing up to 95% of lead and 84% of chromium during the 12-day incubation period. The removal continued through the 12 days and up to the highest value on the 12th day of the experiment. The results revealed that, of the two species, L. gibba was the most efficient for the removal of selected heavy metals. The plants accumulated heavy metals without the production of any toxicity or reduction in growth.

Immobilized Lentinus edodes residue as absorbent for the enhancement of cadmium adsorption performance

To investigate the potential use of Lentinus edodes (L. edodes) residue for Cd2+ adsorption, poly alcohol Na alginate (PVA) was applied to immobilize it. The parameters including contact time, pH, adsorbent dosages, and coexisting metal ions were studied. The suitable pH for immobilized L. edodes was 4-7 wider than that for raw L. edodes (pH 6-7). In the presence of Pb2+ concentration varying from 0 to 30 mg center dot L-1, the Cd2+ adsorption ratios declined by 6.71% and 47.45% for immobilized and raw L. edodes, respectively. While, with the coexisting ion Cu2+ concentration varied from 0 to 30 mg center dot L-1, the Cd2+ adsorption ratios declined by 12.97% and 50.56% for immobilized and raw L. edodes, respectively. The Cd2+ adsorption isotherms in single-metal and dual-metal solutions were analyzed by using Langmuir, Freundlich, and Dubinin-Radushkevich models. The Cd2+ adsorption capacities (q (m)) in single-metal solution were 6.448 mg center dot L-1 and 2.832 mg center dot L-1 for immobilized and raw L. edodes, respectively. The q (m) of immobilized L. edodes were 1.850 mg Cd center dot g(-1) in Cd2+ + Pb2+ solution and 3.961 mg Cd center dot g(-1) in Cd2+ + Cu2+ solution, respectively. The Cd2+ adsorption processes subjected to both adsorbents follow pseudo-second-order model. Mechanism study showed the functional group of L. edodes was -OH, -NH, -CO, and PVA played an important role in metal adsorbing. Mining wastewater treatment test showed that PVA-SA-immobilized L. edodes was effective in mixed pollutant treatment even for wastewater containing metal ions in very low concentration.

Competitive adsorption and desorption of copper and lead in some soil of North China

The competitive adsorption and desorption of Pb(II) and Cu(II) ions in the soil of three sites in North China were investigated using single and binary metal solutions with 0.01 mol·L−1 CaCl2 as background electrolyte. The desorption isotherms of Pb(II) and Cu(II) were similar to the adsorption isotherms, which can be fitted well by Freundlich equation (R2>0.96). The soil in the three sites had greater sorption capacities for Pb(II) than Cu (II), which was affected strongly by the soil characteristics. In the binary metal solution containing 1:1 molar ratio of Pb(II) and Cu(II), the total amount of Pb(II) and Cu(II) adsorption was affected by the simultaneous presence of the two metal ions, indicating the existence of adsorption competition between the two metal ions. Fourier transform infrared (FT-IR) spectroscopy was used to investigate the interaction between soil and metal ions, and the results revealed that the carboxyl and hydroxyl groups in the soil were the main binding sites of metal ions.

Adsorption of Cu (II) from Aqueous Single Metal Solutions by Bagasse Pith Chemically Modified with EDTA Dianhydride (EDTAD)

It was detail studied that the preparation of new chelating materials derived from bagasse pith for adsorption of Cu2+ ion. The bagasse pith was modified by the ethylenediaminetetraacetic dianhydride (EDTAD) and the mechanism of sorption property for heavy metal ion was studied. The FTIR was used to characterize the esterified pith(EP). The results show that the optimal conditions are 24 h of reaction time and 1.5 g of EDTAD dosage and the maximum adsorption capacity for Cu2+ is 76.76mg/g. The peaks at 1743.62 cm−1, 1598.59 cm−1,1408.06 cm−1 in FTIR suggest carbonyl functions in the materials. The Langmuir model can describe the process of adsorbing Cu2+onto EP.

Mycoremediation of Cu(II) and Ni(II)

In the present study, Cu(II) and Ni(II) removal capacity of two filamentous fungi namely, Aspergillus niger van. Tieghem and Rhizopus arrhizus Fischer was evaluated through batch adsorption assays. Batch sorption experiments were performed at 30°C, pH 5.0 and 150 rpm taking biomass amount of 0.2 g. Adsorption trials were carried out as function of initial metal ion concentration within range of 100 to 500 mg/L -1 for both single and binary metal solutions. Results revealed the biosorption capacity of both fungal species significantly increased as the initial concentration of metal ions was raised in the medium. Whereas, adsorption capacity of fungal species significantly decline in binary metal in comparison with single metal solution, desorption and reusability of the biosorbents biomass demonstrated a significantly higher desorption capability of R. arrhizus (> 65%) as compared to A. niger (> 60%) for both metal ions after 4th adsorption/desorption cycle. Batch experiments conducted with real industrial effluents reveled 5 to 10% reduction in sorption potential of test fungi in comparison to capacity obtained with synthetic solution of metal ions.

Extraction of valuable metal ions (Cs, Rb, Li, U) from reverse osmosis concentrate using selective sorbents

The potential of a number of sorbents at extracting valuable metals (Cs, Rb, Li, U) from reverse osmosis brine was evaluated. The experiments, carried out in batch mode, focused on (1) metal sorption onto selected sorbents using single metal solutions, (2) effect of brine salinity on Cs sorption extent, and (3) sorption of Cs and Rb using bi-metallic solutions. Results showed that the hexacyanoferrate-based extractant (CsTreat) was a more promising sorbent for both Cs and Rb than the zirconium phosphate–based material (ZrP), but that any of them was successful at sorbing Li. With regards to U(VI), the resin containing phosphonic and sulphonic groups displayed the highest affinity towards this metal, while ampholyte resins containing amidoxime or aminophosphonic groups performed modestly and the resin containing quaternary ammonium groups proved to be clearly ineffective for the uptake of U(V). Results also revealed that Cs uptake by ZrP decreased with increasing brine salinity, while salinity appeared to hardly influence the Cs sorption onto CsTreat. The sorption results from bi-metallic systems differed moderately from those with single metal systems, indicating that the sorption capacity was not much influenced by any co-ion effect and, thus, that CsTreat was highly selectivite towards Cs and Rb.

Adsorption of heavy metals on amine-functionalized SBA-15 prepared by co-condensation: Applications to real water samples

SBA-15 functionalized with 3-aminopropyltrimethoxy-silane was studied as potential absorbent for Cd 2+, Co 2+, Cu 2+, Zn 2+, Pb 2+, Ni 2+, Al 3+ and Cr 3+. The adsorption capacity and selectivity of the materials were investigated in single and multi-metal solutions. Using single-metal solutions, the adsorbent was found to have an affinity (molar basis) for metal ions in decreasing order of Al 3+ > Cu 2+ > Ni 2+ > Zn 2+ > Co 2+ > Cd 2+ > Pb 2+ > Cr 3+. Using very dilute solutions, i.e., 10 ppm, more than 95% of cations were removed, except Co 2+ and Cr 3+, indicating the high sensitivity of the current adsorbent. The affinity for coexisting metal cations decreased in the order of Al 3+ > Ni 2+ > Cr 3+ > Pb 2+ > Zn 2+ > Cd 2+ > Co 2+ > Cu 2+. The adsorption capacities in multi-metal solutions were lower than in single-metal ones because of competition between metallic elements for the amine groups, with a preference for Al 3+. The amine-modified SBA-15 adsorbent exhibited an excellent selectivity against sodium, potassium, and calcium, indicating that the ionic strength does not affect the adsorption properties. Application of this material to remove copper in tap water, river water, and electroplating wastewater was shown to be successful.

English

The efficacy of the banana peel ( Musa sapientum ) biomass was tested for the removal of lead, copper, zinc and nickel metal ions using batch experiments in single and binary metal solution under controlled experimental conditions. It is found that metal sorption increases when the equilibrium metal concentration rises. At highest experimental solution concentration used (150 mg/L), the removal of metal ions were 92.52% for lead, 79.55% for copper, 63.23% for zinc and 68.10% for nickel while at lowest experimental solution concentration (25 mg/L), the removal of metal ions were 94.80% for lead, 86.81% for copper, 84.63% for zinc and 82.36% for nickel. Biosorption equilibrium isotherms were plotted for metal uptake capacity (q) against residual metal concentrations (C f) in solution. The q versus Cf sorption isotherm relationship was mathematically expressed by Langmuir and Freundlich models. The values of separation factor were between zero and one indicating favourable sorption for four tested metals on the biosorbent. The surface coverage values were approaching unity with increasing solution concentration indicating effectiveness of biosorbent under investigation. The non-living biomass of M. sapientum present comparable biosorption capacity for lead, copper, zinc and nickel metal ions with other types of biosorbent materials found in literature and is effective to remove metal ions from single metal solutions as well as in the presence of other co-ions with the main metal of solution.

Biochar application to metal-contaminated soil: Evaluating of Cd, Cu, Pb and Zn sorption behavior using single- and multi-element sorption experiment

The aim of this study was to evaluate metals (Cd, Cu, Pb and Zn) sorption behavior after biochar application into a metal-contaminated soil. Additionally, two different types of biochar originated from the same organic material (contaminated and uncontaminated) at different application rates (1% and 2% w/w) were evaluated as a novelty of the experiment. Batch sorption/desorption experiments were established to compare the sorption behavior of metals originating from single- and multi-element solutions. Zinc as one of the main contaminants in the studied soil was easily desorbed in the presence of Cu, Pb and to a lesser extent by Cd. This desorption was reduced after biochar application. The obtained results proved the different sorption behavior of metals in the single-metal solution compared to the multi-metal ones due to competition effect. Moreover, during multi-element sorption, Zn was significantly desorbed. The applied biochar enhanced Cu and Pb sorption and no changes were observed when contaminated and uncontaminated biochar was used. Furthermore, the application rate (1% and 2% w/w) had no effect as well. In summary, it is needed to point out that the applied rates of biochars were insufficient for metal immobilization in such contaminated soils.

III. Co-electrodeposition/removal of copper and nickel in a spouted electrochemical reactor.

Results are presented of an investigation of co-electrodeposition of copper and nickel from acidic solution mixtures in a cylindrical spouted electrochemical reactor. The effects of solution pH, temperature, and applied current on metal removal/recovery rate, current efficiency, and corrosion of the deposited metals from the cathodic particles were examined under galvanostatic operation. The quantitative and qualitative behavior of co-electrodeposition of the two metals from their mixtures differs significantly from that of the individual single metal solutions. This is primarily attributed to the metal displacement reaction between Ni(0) and Cu(2+). This reaction effectively reduces copper corrosion, and amplifies that for nickel (at least at high concentrations). It also amplifies the separation of the deposition regimes of the two metals in time, which indicates that the recovery of each metal as a relatively pure deposit from the mixture is possible. It was also shown that nitrogen sparging considerably increases the observed net electrodeposition rates for both metals - considerably more so than from solutions with just the single metals alone. A numerical model of co-electrodeposition, corrosion, metal displacement, and mass transfer in the cylindrical spouted electrochemical reactor is presented that describes the behavior of the experimental copper and nickel removal data quite well.

Competitive adsorption of Cu(II) and Cd(II) ions by chitosan crosslinked with epichlorohydrin–triphosphate

In this study, chitosan (CTS) was crosslinked with both epichlorohydrin (ECH) and triphosphate (TPP), by covalent and ionic crosslinking reactions, respectively. The resulting adsorbent (CTS–ECH–TPP) was characterized by SEM, CHN, EDS, FT-IR and TGA analyses, and tested for metal adsorption. The adsorbent was used in batch experiments to evaluate the adsorption of Cu(II) and Cd(II) ions in single and binary metal solutions. In single metal solutions the maximum adsorption capacities for Cu(II) and Cd(II) ions, obtained by Langmuir model, were 130.72 and 83.75mgg−1, respectively. Adsorption isotherms for binary solutions showed that the presence of Cu(II) decreased Cd(II) adsorption due to a significant competition effect, that is, the adsorbent was selective towards Cu(II) rather than Cd(II).

Removal of Heavy Metal Ions from Aqueous Solutions by Adsorption Using Modified Orange Peel as Adsorbent

In this study, orange peel (OP) was modified by KCl to prepare a novel orange peel adsorbent named as KOP. The adsorption behaviors of KOP for five heavy metals (Cu2+, Cd2+, Pb2+, Zn2+, Ni2+) were studied. The effects of pH, adsorption time and metal ion concentration on single heavy metal solution adsorption by KOP were investigated. All adsorption processes can attain equilibrium with 20min and kinetics data of five heavy metal ions were fitted to pseudo-second-equation; the maximum adsorption capacities for Cu2+, Cd2+, Pb2+, Zn2+and Ni2+were calculated as 59.77, 125.63, 141.84, 45.29 and 49.14 mg/g, respectively. Recycle and reuse experiments indicate that KOP could be used for more than 10 cycles. The effect of coexist metal ions on adsorption can be neglected.

Interactive effects of binary combinations of manganese with other heavy metals on metal uptake and antioxidative enzymes in Brassica juncea L. seedlings

The present study investigates the interactive mechanism involved during the uptake of heavy metals and stress tolerance in Brassica juncea L. seedlings under the influence of Mn(II) in binary combinations with Cr(VI), Ni(II), Co(II) and Cu(II) in terms of changes in antioxidative enzymes-superoxide dismutase (SOD), guaiacol peroxidase (GPX), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR). The order of uptake of heavy metals by the seedlings in single metal solutions was observed to be, Mn>Cu>Co>Cr>Ni. As revealed by multiple regression and path analysis, manganese (Mn) in binary combination with other heavy metals mutually decreased the uptake of each other. Mn and other metals were antagonistic to each other for the activities of SOD, GPX, APX and GR, and decreased the effect of each other through interaction, whereas antagonism between these metals increased the activity of CAT.

The Adsorption Properties of Agricultural and Forest Soils Towards Heavy Metal Ions (Ni, Cu, Zn, and Cd)

Adsorption of Cu, Cd, Ni, and Zn in single and multi-metal solutions by agricultural and forest soils was investigated in batch sorption experiments. The results showed significant differences in sorption capacities of the studied soils. The selectivity order was as follows: agricultural soil≫ top forest soil > bottom forest soil. The adsorption sequence Cu > Zn > Ni > Cd was established for the agricultural and bottom forest soil, while the order for the top forest soil was Cu > Ni > Zn > Cd. The experimental isotherms for the metal sorption were described satisfactorily by the Freundlich and Langmuir models. The competitive adsorption experiment indicated a reduction in the amount of metals adsorbed by the soils from the multi-metal solution compared to the single metal solution. Properties of the soils, such as pH, content of clay and organic matter, exchangeable bases and hydrolytic acidity, showed a significant influence on adsorption capacities of the studied soils.

Biosorption of heavy metals from mining influenced water onto chitin products

Mining influenced water (MIW) emanating from mine sites poses a major environmental concern due to its impact on water contamination caused by low pH and the presence of high concentrations of toxic metals. Chitorem SC-20® (raw crushed crab shells containing 40% (w/w) CaCO3, 30% protein, 20% chitin, 7% moisture, and 3% ash) and Chitorem SC-80® (the chitin polymer containing 88% chitin and 12% moisture) were used to evaluate heavy metals removal from MIW. It was found that SC-20 was very effective at neutralizing the strong acidity of MIW, even at loads as low as 1g/L the equilibrium pH was neutral. At a load of 2g/L, SC-20 showed a final pH of 7.94 with almost complete (>99.8%) removal of iron (120mg/L), lead (1.1mg/L) and zinc (79mg/L), along with partial removal of cadmium (96% of 1.3mg/L), cobalt (54% of 0.78mg/L), copper (42% of 72mg/L), and manganese (64% of 52mg/L) from MIW. Metal removal was achieved primarily by neutralization and precipitation mainly due to the dissolution of the CaCO3 from the SC-20. SC-80 was used to differentiate the effect of alkalinity and the amount of metal adsorption achievable by the chitin polymer. Lead (up to 1.24mg/g), cadmium (up to 1.81mg/g), and cobalt (up to 0.93mg/g) from single-metal solutions were adsorbed onto the chitin polymer (SC-80). Metal adsorption onto the chitin polymer seemed to have a minor role as a mechanism of metal removal from MIW. Overall, this study demonstrated that crab-shell products can be an important alternative for MIW remediation.