Removal Of Nickel Research Articles

Mitigating Health Risks Through Biosorption: Effective Removal of Nickel (II) and Chromium (VI) from Water with Acid-Treated Potato Peels

Introduction: Nickel (Ni(II)) and chromium (Cr(VI)) are associated with serious health risks, including respiratory problems, kidney damage, and cancer, along with potential threats to ecosystems. Given their persistence and significant toxicity, effective removal from contaminated water is essential to mitigate these health risks. This study explores the efficacy of acid-treated potato peels (ATPP) as an economical and readily accessible biosorbent for the removal of Ni(II) and Cr(VI) from water solutions. Methods: The study explored two biosorbents: raw potato peels (RPP) and ATPP. Fourier Transform Infrared (FTIR) spectroscopy was utilized to analyze changes in surface functional groups. Batch biosorption experiments were performed using distinct contact times (30-180min), pH (3–11), and biosorbent dosages (0.1–0.5 g). The Mann-Whitney U test was applied for the statistical analysis. Results and Discussion: The FTIR analysis indicated an enhancement in carboxyl groups on the ATPP surface after acid treatment, with stronger transmittance peak at 1645 cm⁻¹. ATPP showed significant improvements in biosorption capacity compared to RPP, removing 18.23% of 10 mg/L Ni(II) at pH 5 in 120minutes using 0.5 g of ATPP. For Cr(VI), 52.28% removal was achieved at pH 7 with 0.2 g of ATPP within the same time frame. Statistical analysis confirmed the superior performance of ATPP in removing Ni(II) (p = 0.024) and Cr(VI) (p = 0.004). Conclusion: ATPP offers significantly higher biosorption capabilities than RPP attributed to the increased presence of carboxyl groups on the modified surface, indicating potential for eco-friendly effective material in mitigating the heavy metal pollution's health risks.

Investigation of the biological removal of nickel and copper ions from aqueous solutions using mixed microalgae

AbstractThe use of mixed microalgae offers an effective solution for the management of contamination risks in cultivation while enhancing economic viability. In this study, mixed microalgae were used for the first time for the removal of copper (Cu) and nickel (Ni) from aqueous solutions. The characteristics of the adsorbents were examined thoroughly, and the adsorption process was assessed using isotherms, kinetics, and thermodynamics. Particle size, concentration, contact time, temperature, and pH were among the variables assessed. The findings demonstrated that, at an initial concentration of 100 mg L–1 and a pH of 6, the maximum adsorption of Cu with a particle size of 1 mm (90.20%) took place in 60 min. The highest adsorption rate (78.25%) was found for Ni. Microalgae performed best over 180 min at room temperature and at pH values that promoted metal dissolution. The removal percentages of wet and dried microalgae were comparable, and the wet adsorbent was more economical. It was feasible to remove both metals at the same time. Up to three cycles of adsorbent reuse were possible, with sodium hydroxide treatment offering superior removal to hydrochloric acid. Thermodynamic analysis demonstrated that this process, which results in a disordered state, is exothermic and spontaneous.

Optimization and Efficiency of Novel Magnetic-Resin-Based Approaches for Enhanced Nickel Removal from Water

Nickel contamination in water is a critical issue due to its toxicity and persistence. This study presents a novel magnetic resin, developed by modifying Lewatit® MonoPlus TP 207 with magnetite nanoparticles, to enhance adsorption capacity and facilitate efficient separation. A Definitive Screening Design (DSD) was employed to identify and optimize key parameters affecting nickel adsorption, including pH, resin dosage, initial nickel concentration, and the presence of competing ions (calcium and magnesium). The DSD analysis revealed that pH and magnesium concentration were the most significant factors influencing nickel removal. Optimal conditions were determined as pH 7, 270 min contact time, resin dosage of 0.5 mL/L, initial nickel concentration of 110 µg/L, calcium concentration of 275 mg/L, and magnesium concentration of 52.5 mg/L, achieving a maximum removal efficiency of 99.21%. The magnetic resin exhibited enhanced adsorption capacity and faster kinetics compared to the unmodified resin, leading to more efficient nickel removal. Moreover, its magnetic properties facilitated rapid separation from treated water, offering practical advantages for real-world applications. This study demonstrates the effective use of DSD in optimizing adsorption parameters and underscores the potential of magnetic resin as a sustainable and efficient adsorbent for water treatment.

Optimizing the Cementation Process of Leach Solution of Cold Purification Cake: Maximum Removal of Cadmium and Minimum Removal of Nickel

Optimizing the Cementation Process of Leach Solution of Cold Purification Cake: Maximum Removal of Cadmium and Minimum Removal of Nickel

Mycosynthesis of TiO2 nanoparticles using Aspergillus penicillioides for toxic metal removal and photocatalytic applications

Globally, heavy metal pollution, especially lead and nickel, is becoming a problem and is of great concern due to its adverse effects. This study focuses on the eco-friendly biosynthesis of TiO2 nanoparticles using Aspergillus penicillioides metabolites as capping and reducing agents. The myco-synthesized TiO2 nanoparticles were characterized as oblate spherical and applied for photocatalytic removal of lead and nickel from industrial effluent. Optimal conditions for removal included lead and nickel concentrations of 60 μg/mL and 2 μg/mL, 10 μg/mL TiO2 nanoparticle concentration, a pH of 6, and sunlight irradiation. The kinetics and isotherm of adsorption were explained. Effective degradation of lead and nickel by using TiO2 nanoparticles was confirmed by atomic absorption spectroscopy. The nanoparticles demonstrated effective photocatalytic degradation of crystal violet dye achieved a high of 86.9% in 4h and 25% in 2 h, respectively, and showed promising biological activities, including antibacterial, antioxidant, and protein leakage properties. The hemolytic assay confirmed their ecological sustainability for bioremediation. The study highlights the effectiveness of new bio-based TiO2 nanoparticles arbitrated by Aspergillus penicillioides as effective bioremediation agents.

The impact of plasma-activated water on the process of nickel bioremediation by Neowestiellopsis persica A1387

Cyanobacteria provide an economical, feasible, and environmentally friendly solution for heavy metal removal. In addition, plasma can facilitate the removal of heavy metals across various time frames. In this study, we applied plasma-activated water (PAW) to prepare Neowestiellopsis persica A1387 strain medium culture for 0, 10, 15, and 20 min via an Atmospheric Cold Plasma Jet device (ACPJ-17A). Nickel removal efficiency was evaluated after 48 hours of cultivation under controlled conditions at 0, 10, 30, 60, and 90 min. Further investigation was performed through FTIR, GC-MS, and XRD techniques. Statistical analysis of ANOVA and Tukey's test indicated that the samples treated for 15 min had the highest biomass dry weight, polysaccharide content, and nickel removal rate (p ≤ 0.05). The GC-MS analysis presented elevated concentrations of ethanol, 1,3-dimethylbenzene, acetic acid, 3-methylbutyl ester, aromatic chemicals, 2-methyl-1-propanol, and 3-octen-2-ol in all samples treated with plasma. The functional group analysis using the FT-IR approach showed increased peak intensities with more extended treatment periods, indicating the addition of methyl, methylene, and hydroxyl groups to the cyanobacterium cell wall. Furthermore, a peak at 468 cm⁻¹ wavelength was observed, correlating to the Ni-O stretching mode after absorption of Ni on the cyanobacterium surface. The XRD data exhibited prominent peaks in all diffraction patterns angles below 20 degrees, suggesting the presence of amorphous and non-crystalline chemical structures within the cyanobacterial structures. The peak intensity increased with longer treatment durations. The 15-min plasma treatment optimized Ni removal, but the efficiency decreased with prolonged exposure due to adverse effects such as increased reactive oxygen species (ROS) production.

Nickel (II) removal from real electroplating wastewater in an electrocoagulation reactor: parametric optimization by response surface methodology

ABSTRACT Electrocoagulation (EC) process was successfully applied and optimized for the removal of nickel (Ni) from real electroplating wastewater to achieve higher removal efficiency with low energy consumption. In the present study, an electrocoagulation reactor employing iron electrodes was set up for the experimental work. Response surface methodology (RSM) for a four-factorial central composite design (CCD) was applied to study the effects of process parameters on removal efficiency and energy consumption. Maximum Ni(II) removal efficiency of 95.16% was attained on optimization at an applied current of 0.31 A, an initial nickel concentration of 10 ppm, an application time of 18 min, and a pH of 7 along with the energy consumption of 0.443 Wh/g. With the help of the obtained three-dimensional (3D) plots, the interaction between the process variables was evaluated. By analysing the variance (ANOVA), the generated models were successfully validated.

Boron/Fe2+/H2O2 combined with resins process cost-effectively remove Ni(II) in wastewater containing Ni-EDTA: Performance and mechanism

This study proposes a green purification strategy in which mild decomplexation of Ni-EDTA into other Ni complexes facilitates the efficient removal and recovery of nickel through resin adsorption. Decomplexation of Ni-EDTA by boron/Fe2+/H2O2 (B/Fe2+/H2O2) followed by resins adsorption was conducted for Ni(II) removal in Ni-EDTA. The Ni(II) removal efficiency could only achieve 1.3 % and 6.2 % while Ni(II) coexisted with EDTA but more than 10 times of higher when Ni(II) coexisted with EDTA-relatives via the single adsorption of commercial heavy metal-affined resins (D001 and D463), which attributed to the increased binding energies of these Ni-EDTA’s degradation products complexes than Ni-EDTA based on density functional theory (DFT) calculation. In comparing to precipitation, the resin adsorption required much less mineralization of EDTA to have a better removal efficiency of Ni(II). B improved the efficiency of Ni-EDTA decompexation by accelerating the recycle of Fe3+/Fe2+. The EDTA (and TOC) removal enhanced from 48.7 % (4.7 %) to 94.7 % (11.9 %) by B/Fe2+/H2O2 process comparing to Fe2+/H2O2 process. With the high EDTA but low TOC removal efficiency after B/Fe2+/H2O2 treatment, Ni(II) removal efficiency via resins adsorption could maximum achieve 80.5 %, 2–3 times of that via regular precipitation method. In addition, B and resins exhibited good reusability in five cycles, and B/Fe2+/H2O2-resins process had excellent adaptability to different heavy metal complexes. B/Fe2+/H2O2-D463 system not only could reduce 78.4 % reagents cost compared with that of Fe2+/H2O2-precipitation process, but also could save much cost than other processes. The results provide new insights for the cost-effective treatment of EDTA-complexed heavy metal wastewater.

Tailoring the characteristics of polyacrylonitrile nanofiltration membranes for nickel removal from wastewater: The influence of binary solvents and pore-forming agents.

This work presents the results of an investigation on the physiochemical and structural characteristics of polyacrylonitrile (PAN) nanofiltration (NF) membranes prepared using a novel concept of binary solvents for nickel (Ni) removal from wastewater streams. The thermodynamic and kinetic aspects are emphasized aiming to optimize dope formulation, membrane performance, and durability. The fabricated membranes were characterized by scanning electron microscopy (SEM), porosimetry, tensile stress/strain, and flux and rejection. Results revealed that the use of an equal (1:1) mixture of n-methyl-2-pyrrolidone (NMP) and dimethylformamide (DMF) as dope solvents led to the formation of membranes with enhanced performance, offering pure water flux of 2.33 L·m-2·h-1·bar-1 and Ni rejection of 90.84%. Moreover, the incorporation of 0.5wt.% PEG as a pore-forming agent to the dope solution further boosted pure water flux to 4.97 L·m-2·h-1·bar-1 with negligible impact on Ni rejection. Besides attractive performance, the adopted strategy offered membranes of exceptionally high flexibility with no sign of defect or failure especially during module fabrication and testing enabling smooth and hassle-free scale-up and extension to other applications. PRACTITIONER POINTS: Optimized solvent mixture: A 1:1 blend of n-methyl-2-pyrrolidone (NMP) and dimethylformamide (DMF) as solvents resulted in enhanced membrane performance. High flux and Ni rejection: The fabricated membranes exhibited a pure water flux of 2.33 L·m-2·h-1·bar-1 and a remarkable Ni rejection of 90.84%. PEG enhancement: Incorporating 0.5wt.% PEG as a pore-forming agent further improved the membrane's pure water flux to 4.97 L·m-2·h-1·bar-1, without compromising Ni rejection. Exceptional flexibility: The adopted strategy yielded membranes with exceptional flexibility, making them suitable for scale-ups and other applications.

Investigation of demetallization of Ni and V in crude oil using spherical polyelectrolyte brushes with adjuvant

Nickel and vanadium in crude oil adversely affects the quality of petroleum coke and refining process. Polymer brushes bearing high-density ligands have shown promising nickel removal ability. In this work, submicron polybutadiene (PB) grafted by aminodithio- carbamate acrylamide (PAMDTC@PB) was prepared and characterized by the infrared spectroscopy, dynamic light scattering, and elemental analysis. Based on results of molecular simulation, PAMDTC was selected as ligand molecule at first. Then the nickel and vanadium removal rates by PAMDTC@PB and traditional polyacrylic acid brushes (PAA@PB) were evaluated through the electric desalination process, both in the model and real oil samples. The result shows that S atom in AMDTC is most likely to chelate with metal porphyrin compounds and AMDTC molecule presents highest chelating activity. Compared with PAA@PB, the removal rate of Ni and V porphyrin compounds with the aid of PAMDTC@PB increases significantly, with an optimized removal rate of 46.91 % and 56.81 %. To achieve better metal removal efficiency and higher utilization rate of prepared polymer brushes, sodium dimethyl dithiocarbamate (SDD) is introduced into the electric desalination process as a adjuvant. The results indicate that the addition of SDD leads to a increment of 10–30 % to the removal rate of Ni and V and a reduction of brush dosage by 200–400 ppm in the electric desalination process, exhibiting great potential of industrial applications of novel desalination process with adjuvant.

Sodium alginate/banana peels/reduced graphene oxide nanocomposite beads for effective removal of copper and nickel from aqueous solutions

The use of naturally derived nanocomposite beads to remove nickel and copper is gaining more attention due to its relative abundance, low toxicity, and strong affinity toward heavy metals. Most previous studies focus on removing single heavy metals using developed nanocomposite beads. This work prepared sodium alginate/banana peels/reduced graphene oxide nanocomposite beads through simple precipitation using banana peels, reduced graphene oxide, and sodium alginate. The formed nanocomposite beads were characterized and evaluated for the adsorption of nickel and copper from the aqueous phase at neutral pH. The Langmuir isotherm suggests the homogenous adsorption of metals on the surface of the bead. The maximum removal capacity is 85.32 mg/g and 95.79 mg/g for nickel and copper, respectively. This study provides new insight into utilizing banana peels, reduced graphene oxide, and sodium alginate for toxic metal remediation to overcome pollution problems.

Challenges in using Electrocoagulation Process in Removal of Nickel Metal in Wastewater: a Literature Review

In recent years, the surge in nickel production, driven by the growing demand for electric vehicle batteries, has raised concerns regarding environmental consequences. The nickel mining and processing industries contribute to increased nickel levels in wastewater, presenting a serious threat to aquatic ecosystems and human health. This article emphasizes the urgency of developing effective technologies for treating nickel-contaminated wastewater. Electrocoagulation emerges as a promising method, providing high efficiency, minimal sludge production, and cost-effectiveness. The article critically and systematically reviews the potential of the electrocoagulation process in nickel removal from wastewater. In the review, we identify and analyze nearly 32 studies published from 2013 to 2023. We discuss contaminant removal mechanisms and analyze trends in the use of operational parameters. This article identifies the most commonly applied conditions: aluminum electrodes, inter-electrode spacing ≥ 1 cm, current density ≤ 10 mA/cm², initial pH 6 ≤ pH < 11, electrolysis time < 60 min, batch operation, and initial nickel concentration > 50 mg/L. This comprehensive review serves as a foundational resource for advancing electrocoagulation technology in the removal of heavy metals from nickel wastewater.

Exploration of polymer inclusion membrane for nickel recovery from waste printed circuit boards

In this study, the selective recovery of nickel ions from waste printed circuit boards (WPCBs) solution through polymer inclusion membranes (PIMs) containing 5-nonylsalicylaldoxime (ACORGA M5640) as extracting agent and polyvinyl chloride (PVC) as base polymer has been explored. The proposed method utilizes combined process of solvent extraction and PIMs route for the recovery of nickel. As a first step, the copper was solvent extracted using ACORGA M5640 by the previously developed method by our group and further the raffinate of first stage is utilized as feed phase for the nickel recovery. The consequence of carrier concentration on transportation of nickel, pH of feed solution and effect of acidity of stripping agent has also been investigated. The increase in carrier concentration increases the nickel removal efficiency from feed phase to strip phase. Moreover, the increase in concentration of strip phase also increases the nickel ion flux. 99.77 % nickel was selectively recovered from leach liquor using PIMs containing 50 % of ACORGA M5640. Further, PIMs stability and transport studies has been carried out to know the feasibility of its use in recycling of electronic waste.

Process and kinetics of ammonium sulfide removal of zinc, nickel and cobalt from manganous sulfate electrolyte

In producing electrolytic manganese and manganese-based lithium batteries, Manganous sulfate solution serves as a crucial intermediate material. During the preparation of manganese sulfate solution by acid leaching, the removal of impurities such as zinc, nickel, and cobalt ions by sulfide precipitation is essential for obtaining high-quality metallic manganese and high-purity manganese sulfate. The results show that when the temperature is 45 °C, the pH is 5.60, the ammonium sulfide dosage is 40 %, the time is 5 min, and the rotation speed is 650 rpm, the sulfidation rates of zinc, nickel and cobalt are 99.07 %, 89.30 %, and 87.70 % respectively. At this time, the loss rate of manganese in the solution after sulfide impurity removal is 11.45 %, and the manganese-impurity ratio is 80.00. Response surface methodology analysis revealed that temperature, pH, and ammonium sulfide concentration significantly affected the manganese loss rate. After process optimization, at a temperature of 32.70 °C, a pH of 5.20, and an ammonium sulfide concentration of 32.73 %, the manganese loss rate decreased to 6.05 %, while the removal rates of Ni, Co, and Zn were 75.35 %, 60.80 %, and 99.51 %, respectively. In the Manganous sulfate electrolyte with or without ammonium sulfate, the sulfide precipitation processes of zinc, nickel and cobalt ion are all first-order reactions, and the reaction order is zinc > nickel > cobalt. More importantly, the density functional theory (DFT) calculation results also confirmed the formation sequence of zinc sulfide > nickel sulfide > cobaltous sulfide, which supported the experimental results well. This study will lay the foundation for process optimization and mechanism elucidation of impurity ions in ammonium sulfate electrolyte precipitated by ammonium sulfate.

Removal of Chromium ions (Cr6+) and Nickel ions (Ni2+) from Simulated Industrial Wastewater Using Flow-by-Porous Electrode

The quality of water is significantly impacted by the presence of Cr6+ and Ni2+ ions. This study investigates the effectiveness of a flow-by porous graphite electrode cell in removing these contaminants from simulated industrial wastewater. We explore the impact of various factors on the removal process, demonstrating the method's potential for efficient removal. The initial concentration of nickel and chromium ions (20 to 80 mg/l and 20 to 100 mg/l, respectively), the feed flow rate (0.28 to 1.11 ml/s), current density (0.2 to 2.25 mA/cm2) and pH all influence the removal rate and efficiency. A higher feed flow rate negatively affects the removal efficiency of both Ni2+ and Cr6+ ions. Nickel removal efficiency decreased by 34.9% at 20 ppm and 26% at 80 ppm, representing the highest and lowest reductions in efficiency, respectively. Chromium removal efficiency decreased by 19% at 100 ppm and 6.5% at 50 ppm, indicating the highest and lowest reductions in efficiency, respectively, under the same flow rate change. Under optimal conditions, the removal efficiency for Ni2+ was 99.47% after 15 min of operation at a current density of 1.96 mA/cm2, a flow rate of 0.28 ml/s, and a pH of 8 and the removal efficiency for Cr6+ was 99.97% after 10 min of operation at a current density of 2.25 mA/cm2, a flow rate of 0.28 ml/s, and a pH of 2. The flow-through porous electrode system achieves efficient heavy metal removal with operating costs of 0.24 USD/m3 for nickel and 0.38 USD/m3 for chromium at optimal conditions.

Investigations on the biosorption of nickel using tea leaves and tea fibre (Camellia Sinensis) as adsorbents: thermodynamics, isotherms and kinetics

The adsorption behavior of tea leaves and tea fiber (Camellia sinensis) as low-cost adsorbent with respect to nickel was investigated to justify its usage in wastewater treatment. A good number of adsorption constraints were investigated which provides information about the effect of pH value, temperature, adsorbent dosage, time of contact as well as the starting concentration of the simulated system on the sorption process itself. From the result effects of these parameters could be seen in the biosorption of Nickel by both the tea leaves and fibers. The optimal pH for Ni biosorption in tea leaves and fiber is between 3 and 5, with the highest removal at pH 5 and a dosage of 3 g. The leaf adsorbent is more effective at 50 mg/L metal ion concentration showing 99.8% Nickel removal. The kinetics was best described by the pseudo-second order which gave the most convincing fit. The Langmuir isotherm gives R2 values of 0.990 and 0.985 for tea leaves and tea fiber and Freundlich isotherm gives 0.985 and 0.980 values for tea leaves and tea fiber correspondingly with the Langmuir isotherm having higher R2 values considered the most suitable. In the long run, this process was endothermic, spontaneous, and of course thermodynamically feasible hence, the adsorbent was considered fit for wastewater treatment.

A comparative study of calcium oxide nanoparticle and its ferrite (CaO/Fe2O3) nanocomposite for removal of zinc and nickel from electroplating effluent

Electroplating effluent contains many heavy metals including Zinc (Zn) and Nickel (Ni) are some of the crucial metals which exist in high concentrations. Calcium Oxide nanoparticles (CaONPs) and CaO/Fe2O3 nanocomposite (CaO/Fe2O3NC) were synthesized to evaluate the feasibility of Zn (II) and Ni (II) removal from wastewater. CaO NPs were successfully synthesized from waste eggshells by the sol–gel process while the chemical precipitation method was used for the synthesis of CaO NC. The morphology of the prepared material was characterized by X-ray diffraction (XRD), DLS, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) analysis. Batch studies were performed to assess the effect of pH, time, and adsorbent dose on the adsorption efficiency of the nanoparticle and nanocomposite for Zn (II) and Ni (II) removal. Inductively coupled plasma mass spectroscopy (ICP-MS) was used to monitor the amount of Zn (II) and Ni (II) ions in the aqueous solutions. The adsorption capacity of both metal ions increases with an increase in pH, with maximum adsorption occurring at pH 8. An optimum dose of 75 mg/L was observed with both CaO nanoparticle and CaO/Fe2O3 nanocomposite to remove Zn (II) and Ni (II) while equilibrium was achieved after 1 h. The high adsorption capacity makes these adsorbents a promising candidate for removal of metal ions from electroplating effluent.

Strychnos potatorum seeds derived magnetic graphene oxide nanocomposite for removal of nickel from wastewater: Adsorption performance, isotherm, kinetic and desorption behavior

In the present study investigates the adsorption of nickel ions by Strychnos potatorum seeds derived magnetic graphene oxide (SP-MGO). The fitness of the derived material was analyzed using BET and zeta seizer which proves the suitability of this adsorbent for adsorption process. The surface area, pore size and pore volume were obtained through BET analysis and the results were 51.798 (m2/g), 16.795 nm and 0.217 (cm3/g) respectively. And the size of the nanoparticle was measured using zeta seizer. For achieving maximum adsorption capacity, the following optimized conditions were; 60 min of contact time, under pH of 8, with 10 mg of SP-MGO dose, for the concentration of 10 mg/l, at the temperature of 35 °C. Freundlich isotherm (R2 =0.999) and pseudo second order (R2 =0.997) was well described the adsorption process. According to the isotherm model the adsorption of nickel ions occurs by multilayer of adsorption on heterogeneous surface of SP-MGO nanoadsorbent and also by chemisorption according to kinetic model. The Langmuir monolayer adsorption capacity (Q max) obtained by SP-MGO was 6.66 mg/g. The regeneration ability of SP-MGO was only reduced 17.1 % even after five cycles of adsorption runs. Overall, the SP-MGO can be a potential option for develop into a commercial adsorbent for industrial use to eliminate the pollutants from waste water.

Biosorption of copper, nickel, and manganese as well as the production of metal nanoparticles by Bacillus species isolated from soils contaminated with electronic wastes.

Improper electronic waste management in the world especially in developing countries such as Iran has resulted in environmental pollution. Copper, nickel, and manganese are from the most concerned soil contaminating heavy metals which found in many electronic devices that are not properly processed. The aim of this study was to investigate the biological removal of copper, nickel, and manganese by Bacillus species isolated from a landfill of electronic waste (Zainal Pass hills located in Isfahan, Iran) which is the and to produce nanoparticles from the studied metals by the isolated bacteria. The amounts of copper, nickel, and manganese in the soil was measured as 1.9 × 104 mg/kg, 0.011 × 104 mg/kg and 0.013 × 104 mg/kg, respectively based on ICP-OES analysis, which was significantly higher than normal (0.02 mg/kg, 0.05 mg/kg, and 2 mg/kg, respectively. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of metals on the bacterial isolates was determined. The biosorption of metals by the bacteria was evaluated by inductively coupled plasma optical emission spectroscopy (ICP-OES). The metal nanoparticles were synthetized utilizing the isolates in culture media containing the heavy metals with the concentrations to which the isolates had shown resistance. X ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) were used for the evaluation of the fabrication of the produced metal nanoparticles. Based on the findings of this study, a total of 15 bacterial isolates were obtained from the soil samples. The obtained MICs of copper, nickel, and manganese on the isolates were 40-300 mM, 4-10 mM, and 60-120 mM, respectively. The most resistant isolates to copper were FM1 and FM2 which were able to bio-remove 79.81% and 68.69% of the metal, respectively. FM4 and FM5 were respectively the most resistant isolate to nickel and manganese and were able to bio-remove 86.74% and 91.96% of the metals, respectively. FM1, FM2, FM4, and FM5 was molecularly identified as Bacillus cereus, Bacillus thuringiensis, Bacillus paramycoides, and Bacillus wiedmannii, respectively. The results of XRD, SEM and EDS showed conversion of the copper and manganese into spherical and oval nanoparticles with the approximate sizes of 20-40 nm. Due to the fact that the novel strains in this study showed high resistance to copper, nickel, and manganese and high adsorption of the metals, they can be used in the future, as suitable strains for the bio-removal of these metals from electronic and other industrial wastes.

Energy efficient electrocoagulation using brass electrode for simultaneous nickel and chromium removal from synthetic wastewater: Cost and parametric evaluation

Electrocoagulation process using brass anode was designed for simultaneous removal of nickel (Ni) and chromium (Cr (VI)) from synthetic wastewater. In the present work, the effect of current density (Cd) 13.16–65.79 A/m2, the concentration of chromium (CC) and nickel (CN): 10–50 mg/L, pH: 2–10, Electrode distance (Ed): 0.7–3.5 cm, types of electrode material, and supporting electrolyte have been studied on the nickel and chromium removal. The brass electrode demonstrated Cr(VI) and Ni removal percentages of 99.9 % and 99.38 % respectively at concentration of Cr(VI) = Ni = 50 mg/L, Cd = 65.79 A/m2, Ed = 0.7 cm, EC time = 50 min at the initial pH of synthetic wastewater. In addition, the brass electrode demonstrated better performance with lower energy consumption (21.58 kWh/m3) and less operation cost 1.797 US$/m3) as compared to Al, Fe and Cu electrode materials.