Metal Removal Process Research Articles

Removal of iron from salt water entering the chlor-alkali membrane system using activated carbon adsorbent to reduce environmental damage

Heavy metal ions have deadly and deadly effects on all life forms and enter the food chain through the disposal of waste in water channels. One of the most important heavy metals is iron. There are several methods used to remove heavy metal ions. The adsorption method is widely used due to its easy operation, low energy consumption, easy maintenance, high adsorption capacity and high efficiency. Activated carbon as an adsorbent with high adsorption capacity and low cost, has many applications in heavy metal removal processes. The purpose of this paper is to remove iron (III) ions from brine entering the chlorinated alcohol system using activated carbon adsorbent to reduce environmental damage.In order to achieve this goal, after preparation of activated carbon adsorbent, and its contact with salt water of chlor-alkali unit containing iron (III) ion, the effect of adsorbent amount factors (0.5 to 2 g / l), contact time (15 to 120 minutes) and pH (3 to 9) were assessed.Based on the results of this study, pH = 7 was determined as the optimal pH and 90 minutes as the equilibrium time. with increasing the amount of adsorbent, the removal percentage increased and the maximum removal percentage of iron ions in the amount of 2 g / l of activated carbon adsorbent was obtained. Also, the effect of contact time, pH and the amount of activated carbon adsorbent on the process of iron ion removal was significant (p <0/05).

Sustainable milling of Ti-6Al-4 V super alloy using AlCrN and TiAlN coated tools

Majority of the heat energy generated during the metal removal processes disperses with the help of cutting fluids, which possess numerous challenges to environment and mankind. Dry machining with the help of coated tools is a sustainable alternative to eliminate the cutting fluids. The present work investigates the influence of AlCrN and TiAlN coating during the end milling of high-performance Ti-6Al-4 V super alloy. Experiments were also performed at high-speed condition where coated tools were employed in dry condition and uncoated tools in the presence of cutting fluid. For both the conditions, force, tool wear, surface roughness and surface morphology were investigated. The resultant force generated by the AlCrN and TiAlN coated tool under dry condition is comparable to that of uncoated tool under wet condition. It is observed that the chipping of cutting is the major mode of failure of cutting tool. This was evident while machining with uncoated tool under low-speed condition. AlCrN coated tool gave better surface finish when compared to TiAlN coated tool. At various operating conditions, various defects such as redeposition of material, side flow, presence of black spot were observed.

Tunning the defects in lignin-derived-carbon and trimetallic layered double hydroxides composites (LDH@LDC) for efficient removal of U(VI) and Cr(VI) in aquatic environment

Utilizing different absorbents to remove heavy metals from aquatic environment has been extensively investigated because of its simple operation, good reusability, and low cost. The removal efficiency of these adsorbents, nevertheless, need to be further enhanced to meet the practical requirement. In this study, we demonstrate defect engineering as an effective approach to enhance the performance of biochar-based composites for U(VI) and Cr(VI) removal. Lignin derived carbon and Ca/Fe/Al-trimetallic layered double hydroxide composites (LDH@LDC) is prepared by hydrothermal method. Defects are introduced into the LDH layer by H2 plasma treatment. The obtained defective LDH@LDC exhibits outstanding removal efficiency for U(VI) (267.65 mg/g at pH = 5.0, T = 308.15 K, CInitial = 30 mg/L), which is much higher than LDH@LDC as-prep (190.47 mg/g at pH = 5.0, T = 308.15 K, CInitial = 30 mg/L). Similar defect-induced enhancement is observed for the removal of Cr(VI). The thermodynamic and kinetic studies of the removal process, as well as the surface analyze suggest that the removal mechanism of U(VI) and Cr(VI) by the as-prepared and plasma-treated LDH@LDC were both dominated by ion exchange. The plasma treatment introduces defects into the LDH layer, which effectively promote the ion exchange between the LDH layer and the heavy metal in the aquatic environment, leading to strongly enhanced removal performance. This study clarifies the critical role of defects in heavy metal removal process and provides a new pathway of designing high performance absorbents for water remediation.

Selective Removal of Pb From Aqueous Phase by HGMS and Ion-Imprinted Magnetic Adsorbent

A selective removal of certain ions from aqueous phase containing common ions is very useful in engineering aspect because the process allows removal of toxic substances only or recovery of valuable ion species. The ion imprinting technology has shown great potential in the synthesis of materials that are capable of adsorbing a metal ion selectively. In current study, a Pb (II) imprinted magnetic polymer was synthesized using surface imprinting technique employing Pb (II) as template, polyethyleneimene functionalized magnetic Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> as functional monomer and epoxy chloropropane as cross-linker. The magnetic adsorbent was successfully imprinted, and the ion imprinted sorbent was used for selectivity test for Pb (II). Through the imprinting process, the shape of sorbent has changed, and the magnetic properties have decreased. This is an adverse effect of the polymer formed on the surface of the sorbent by the imprinting. The synthesized magnetic adsorbent was recovered from aqueous phase by a high gradient magnetic separation (HGMS) system with a superconducting magnet. The magnet is a cryo-cooled Nb-Ti superconduction magnet. Magnetic filter (SUS 403, 10 mesh) was used for the magnetic separation. The synthetic polymer with small particle size and weak magnetic properties successfully recovered the by the HGMS system and the recovery efficiency was improved with increased magnetic field of the superconducting magnet. By the magnetic separation, the adsorbent could be recovered and reused after the selective adsorption process for a heavy metal removal. The prepared Pb (II) imprinted magnetic adsorbent was also characterized by transmission electron microscope (TEM) and vibrating sample magnetometer (VSM). Batch selectivity studies were performed to evaluate the influence of competing ions such as Cd (II), Ni (II), and Cu (II). The selectivity coefficients of Pb (II)/Cd (II), Pb (II)/Ni (II) and Pb (II)/Cu (II) were calculated as 1.89, 3.57 and 11.23 respectively.

Insights into the Recent Use of Modified Adsorbents in Removing Heavy Metal Ions from Aqueous Solution

Natural water gets contaminated with heavy metal ions because of industrial effluents' discharge into the aquatic environment. As these heavy metal ions cause various health hazards, they should be removed from the aqueous solution. Heavy metal ion concentration in the aqueous solution is very less, so conventional metal removal and recovery processes cannot be applied here. The adsorption method is a great alternative to all these processes as it is a cost-effective and easy method. The use of natural, low-cost materials as adsorbents is eco-friendly also. However, metal uptake capacity of low-cost materials is very less. So, modification is required for low-cost materials to increase their efficiency. In the present review, different modification procedures adopted by different researchers have been discussed. Different low-cost materials used are sawdust, fruit and vegetable wastes, soil, minerals, etc. The modifying agents are heat, acids, bases, and other chemicals. Nevertheless, most of the studies are limited to batch tests only. Future research should be carried out on the extension of batch tests to column study for the large-scale treatment of contaminated water, and the cost of modification procedures and their impact on the environment should also be assessed.

Use of Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans in the Recovery of Heavy Metals from Landfill Leachates

Among the methods used to remove metals and their compounds from landfill leachates with low application costs and high efficiency are bioleaching and biosorption. The most effective bacteria used in the metal removal process are Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. The aim of the study was to determine the usefulness of the A. ferrooxidans and A. thiooxidans population in removing heavy metals from landfill leachate. In addition, development opportunities for bacterial population using landfill leachate as growth medium were identified. The substrate for the research was the raw leachate before the reverse osmosis process. In order to increase the efficiency of trace elements removal and recovery from leachate, variable combinations have been used which differ by the addition of sulfuric acid, A. ferrooxidans culture, A. thiooxidans culture, mixed culture containing populations of both bacteria, and elemental sulfur. Based on the research, it was found that the removal of heavy metals from leachate was a selective process. High bioleaching efficiency, from 80% to 90%, was obtained for all metals for which the sample acidification or sulfur addition was used. The simultaneous combination of both these additives turned out to be the most advantageous. The A. thiooxidans culture was the most effective in bioleaching reverse osmosis effluents. For the A. ferrooxidans culture used, much lower efficiencies were obtained, while by contrast, the use of mixed culture of two bacterium species had no significant effect.

Removal of Heavy Metals during Primary Treatment of Municipal Wastewater and Possibilities of Enhanced Removal: A Review

Resource reuse has become an important aspect of wastewater management. At present, use of sludge in agriculture is one of the major reuse routes. Conventional municipal wastewater treatment does not involve any designated process for removal of heavy metals, and these distribute mainly between effluent and sludge. Enhanced removal of heavy metals during primary treatment may decrease the heavy metal concentrations in both effluent and sludge from secondary treatment and promote long-term reuse of secondary sludge. This review considers heavy metal occurrence and removal during primary settling, together with possible treatment technologies for heavy metal removal in primary settlers and their theoretical performance. The variation in total heavy metal concentrations and dissolved fraction in raw municipal wastewater points to a need for site-specific assessments of appropriate technologies for improved heavy metal removal. Studies examining the heavy metal speciation beyond dissolved/particulate are few. Missing or disparate information on process parameters such as hydraulic retention time, pH and composition of return flows makes it hard to generalize the findings from studies concerning heavy metal removal in primary settlers. Coagulation/flocculation and use of low-cost sorbents were identified as the most promising methods for enhancing heavy metal removal during primary settling. Based on the available data on heavy metal speciation and removal during primary settling, sorption technologies may be most effective for enhancing the removal of Cu and Ni, while coagulation may be efficient for Cd, Cr, Cu, Pb, Zn and Hg removal (but not as efficient for Ni removal).

Effective use of activated carbon from olive stone waste in the biosorption removal of Fe(III) ions from aqueous solutions

The pollution of industrial wastewater by heavy metals introduces a large number of iron ions, which constitute a hazard to human life even at trace concentrations. Most processes for the treatment of wastewater with Fe(III) ions and others heavy metals today are based on chemical physical methods. They have the disadvantage of generating a secondary sludge, which always requires additional treatment. This makes the heavy metal removal process more expensive. In contrast, the biosorption process has proven in recent years to be an alternative, economical and efficient process for the treatment of wastewater that is contaminated by metals. This paper proposes the use of Multi-Response Surface with desirability functions (MRS) to optimize the process of biosorption using activated carbon from olive stone waste to remove Fe(III) ions from aqueous solutions. The study has been validated on a laboratory scale, is not technically demanding, is environmentally friendly and involves a cost that will be acceptable to the industrial wastewater for economic reasons. Several parameters or inputs of the biosorption process were considered. They included the initial iron concentration, biosorbent dosage, process temperature, agitation time and mixing speed. However, the concentration of Fe(III) ions that are present in the treated wastewater is the variable to optimize in three optimization scenarios when the minimum, mean and maximum values of initial iron concentration appear in their study range (lower, intermediate and higher value). These scenarios were based on a desire to obtain the maximum elimination of Fe(III) for any value of parameters or inputs of the biosorption process, maximum elimination of Fe(III) when the energy consumption of the adsorption process was minimized, and maximum elimination of Fe(III) when the biosorbent dosage was minimized. The proposed adsorption process achieved a maximum Fe(III) elimination of 99.51%, 99.24% and 99.49% for the first, second and third optimization scenarios respectively when, in all cases, the initial iron concentration was 55 mg/L. Agreement between the experimental and predicted results indicates that activated carbon that is derived from olive stone waste can be used as a biosorbent.

Application of machine drive oscillations for chip breaking in heavy duty turning operations

The quality of many metal removal processes is partially defined by the chip formation process. The creation of long chips is one of the main problems in continuous processes like turning. The long chips can scratch the final part surface and generate production stops for manual chip removal. In this article, a technique called modulation-assisted machining is used to vary the chip thickness and force the chip breakage. For the heavy duty applications considered here, the oscillation is generated by the ordinary drives of the machine. The limits of the drives are taken into account and the system automatically selects the most appropriate oscillation parameters according to the machine oscillation capability and process parameters. Experimental validations show the effect of this system on the chip length and surface finish.

Computational analysis of machining characteristics of surface using varying concentration of nanofluids (Al2O3, CuO and TiO2) with MQL

When the Nanoparticles are mixed at different concentration in Basefluid, are called Nanofluid. By the addition of different nanoparticles at different concentration in different basefluid we get the enhancement of different-different properties which we are going to analyze in this paper. In this article, we are going to analyze the nanoparticles (Al 2 O 3 , CuO and TiO 2 ) at concentration (0%, 1%, 2%, 3%, 4%, 5% and 6%) into the basefluid (water) through MATLAB and obtain the different input parameters like Thermal Conductivity; Specific Heat; Viscosity; Density and we get that during different parameter analysis different nanofluids shows their property enhancement hence we can we different nanoparticles during different machining process according to the properties we required for machining. After that we do a theoretical study that how these input parameters affect the output parameters like Surface Roughness, Machining Temperature, Chip Morphology, Tool Wear, Coefficient of Friction, etc. during the machining or metal removal process. The summary and conclusions are also presented on basis of data collected and some area for future research is also identified.

Modeling and Characterization of Aisi S-7 Steel Using the Johnson Cook Model – an Explicit Analysis

: A two dimensional, uniformly distributed grains model has been developed for AISI S-7 grade Steel and the orthogonal machining process, in the pursuit of determining the various effects of temperature rise, residual stresses, chip morphology, and strain hardening. A Johnson-Cook material model, along with a numerical, technique was used to simulate the machining process using ANSYS 15 academic license. The machining has been carried out at different velocities: 60, 70, and 80 ms-1 and with depths of cut of 2, 3, and 5 mm. Results revealed that the accumulation of tandem grains offers a maximum resistance ahead of the tool-chip interface due to the strain hardening effect, during the metal removal process. This effect leads to a maximum rise in temperature up to 912.59 °C, which has been observed in the secondary shear zone. Serrated chip flow was observed mainly at a low speed of 60 ms-1. The Strain hardening effect was more substantial at 60 ms-1 and 5 mm depth of cut compared to any other machining parameters. A great deal of discussion has been made on the above material machining process that may serve as a useful resource to the tool designer and manufacturing scientist.

Frictional force during machining process Part 2: Influence of process parameters

In manufacturing, metal removal process is a vital activity which defines the productivity of the organization. The metal removal during machining operations, depend on factors which include cutting tool, work piece material, cutting fluids, machine tool condition, process parameters etc. In the present work, an effort has been made to understand the behavior of frictional force (Ff) during turning operation. Experiments were designed and executed with selected set of process parameters. The Ff for each trial was computed based on the Merchant’s circle diagram. The influence of each machining parameter on Ff has been analyzed and quantified for each parameter. The investigation reveals that feed rate and depth of cut has direct consequences on Ff , whereas spindle speed has indirect impact.

Supervision of Milling Tool Inserts using Conventional and Artificial Intelligence Approach: A Review

Due to continuous cutting tool usage, tool supervision is essential for improving the metal cutting industry. In the metal removal process tool, supervision is carried out either by an operator or online tool supervision. Too... | Find, read and cite all the research you need on Tech Science Press

Experimental investigation of surface roughness and cutting force during machining of SS43100 by using coated and uncoated carbide inserts

Machining processes are the accurate metal removal processes for shaping components in the manufacturing industry. The main challenges of the manufacturing industry are to increase productivity and quality. Manufacturing industries are trying to reduce the cost of machined parts which are manufactured by different machined methods. Machining hard metals is a challenging task. In the presented research work machining parameters were investigated for machining of SS43100 by using coated and uncoated carbide tool inserts. Carbide tool inserts were coated by Ti16Zr using the PVD method of coating. Experiments were performed during the turning operation of SS43100 by coated and uncoated tool inserts. Cutting speed range were 150r.p.m, 250 r.p.m., 350 r.p.m., feed were 0.085 mm/rev, 0.095 mm/rev, 0.1 mm/rev. and depth of cut was 0.1 mm, 0.15 mm, and 0.2 mm selected as controlling factors. Surface roughness and cutting force were selected as response factors. Digital lathe tool dynamometer was used for cutting force measurement and ITI surface tester RS232 was used for surface roughness measurement. In the experimental study and analysis of output response parameters, Taghuchi L9 orthogonal array model has used The results obtained were optimized using the Taghuchi technique for cutting forces and surface roughness. The Taghuchi technique was performed for combinations of each input variable in linear fit model multivariate analytics. Experimental results were compared and models established supported by evidence.

Retracted] Impact of Different Electrolytes on the Machining Rate in ECM Process

Electrochemical machining is a nonconventional machining process in which the metal removal is achieved by the electricity and chemical solution known as an electrolyte. It is the reverse electrolysis process where the application of electricity facilitates the current travel in between anode and cathode. The mechanism of the ion movement is similar to the electrolysis process. Electrochemical machining (ECM) is a type of advanced machining process which employs electricity to perform the machining process on the workpiece. It is also known as a reverse electroplating process where metal removal is achieved instead of metal deposition on the metal surface. There are various parameters that affect the metal removal process in the ECM process, such as electrolyte, power supply, workpiece material, and tool material. The electrolyte is one of the key factors impacting the machining rate, surface finish, and reliability of the produced parts. In this project, a brief study is carried out regarding the electrochemical process and the electrolytes where the properties, functions, merits, and demerits are evaluated. The impact of the various electrolytes and their suitability for machining of various metals is also discussed. The findings of the effect produced by using the mixture of the electrolyte in the electrochemical machining process are discussed in this project. The effects of the complexing agents on the electrolyte and the electrochemical process as a whole are also reviewed.

Innovative polymer-complex draw solution for copper(II) removal using forward osmosis

In forward osmosis (FO) process, reverse solute flux (RSF) is considered as a major disadvantage that limits the potential of FO. In this study, an innovative approach to reduce RSF was developed by introducing complexing agent into draw solution (DS) containing magnesium chloride (MgCl2). A water-soluble complexing agent namely poly(sodium 4-styrenesulfonate) (PSS) was chosen for this study and its affinity towards complexation with MgCl2 was investigated in terms of its loadings (0.1–5.0 w/w%) and pH condition (3.0, 5.0, 7.0 and 9.0). It was found out that the addition of PSS was able to reduce the effect of RSF due to its complexation with MgCl2 which enhanced the molecular weight and inhibited the movement of MgCl2 across thin film composite (TFC) membrane. Under pH studies, it is demonstrated that the optimum DS condition for complexation affinity was at none-adjusted pH. Compared to RSF value without the PSS addition, reduced RSF value (0.3 g/m2.h) was achieved at 1.0 w/w% PSS. When copper(II) sulphate was used as feed solution, the rejection was maintained at an average value of 95%. Based on these findings, this study promotes the feasibility of polymer-complex DS to be used in FO process for heavy metals removal.

Central composite design of heavy metal removal using polymer adsorbent

The industrial effluents of heavy metal become a great concern because of their toxicity. The better design of experimental (DOE) should be applied for an efficient treatment process. The statistical DOE of central composite design (CCD) can be used for the optimization process of heavy metal removal. The cadmium ions (Cd2+) and lead ions (Pb2+) were removed using amidoxime modified poly(acrylonitrile-co-acrylic acid) (poly(AN-co-AA)). The CCD response result (Cd2+ and Pb2+ removal) was obtained by considering independent variables of pH (A), adsorbent dosage (B), and initial concentration (C). The experimental removal of Cd2+ and Pb2+ at optimum conditions was 98.90% and 99.99%, respectively. The regression analysis illustrated the optimum conditions were 10 mg.L−1 Cd2+ concentration with 4.66 g.L−1 adsorbent at pH 9.31, and 20 mg.L−1 Pb2+ concentration with 8.27 g.L−1 adsorbent at pH 9.08. Both of the metal ions yielded insignificant lack of fit of the analysis of variance (ANOVA).

Tribological behavior of the boric acid and titanium dioxide based nanofluid in machining of EN24 steel

Turning operation is a widely recognized metal removal process in the industry. If the machining were not run efficiently, it may affect the performance of the tool and the work piece by generating higher cutting forces and the temperature as in hard steel. To minimize these effects, lubrication has to be effective in reducing these forces and lowering the tool temperature. In the present study, machining experiments were conducted on EN24 steel with the application of nano sized boric acid (50 nm) as the solid lubricant that is mixed with titanium dioxide (100 µm) in SAE 40 oil. Turning tests are conducted using tungsten carbide tool inserts under dry, wet and MQL conditions to measure and compare the cutting forces, tool temperatures and roughness of the work piece. Results indicate that boric acid enables significant reduction in the cutting forces which in combination with the titanium dioxide helps to improve the heat dissipation; an advantage that makes such lubricants an effective cutting fluid. H3BO3 and TiO2 based nanofluid resulted in reducing the surface roughness of up to 2.7 µm that is a re-duction by ~15%.

Metal-sulfide dynamics in a constructed wetland in the Southeastern United States

The Tritium Processing Facility at the Savannah River Site releases effluent containing copper (Cu), zinc (Zn), and lead (Pb) to the H-02 constructed wetland for remediation before the final release. Sediment cores were collected in the wetland cells in both summer and winter. Concentrations of total metals in all sediment layers and acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM) in surface sediments were determined. Total metal concentrations suggested most metals removed from surface water were retained by the organic-rich flocculent in the top sediment layers instead of being transported to the deeper sulfide mineral layers. The seasonal difference of AVS and SEM indicated a season-related sulfur cycle and metal removal process in the wetland cells. SEM-Zn was the major contributor to total SEM. Metals accumulating in surface sediments were mainly sequestered in AVS and SEM extractable phases including metal-sulfides and organic matter complexes. The general SEM/AVS ratio was > 1, demonstrating the metals associated with sediments were potentially mobile and/or bioavailable, which becomes a concern for the long-term sustainability of the constructed wetland. The disturbance event in the sediment triggered the release of total metals, which were mostly in particulate form and were not bioavailable. Due to the high levels of reduced ion (Fe) in the sediment, the released particulate metals were likely to form metal-scavenging particulate Fe3+ oxyhydroxides under oxic conditions.

Experimental study and parameters optimization of microalgae based heavy metals removal process using a hybrid response surface methodology-crow search algorithm

This study investigates the use of microalgae as a biosorbent to eliminate heavy metals ions from wastewater. The Chlorella kessleri microalgae species was employed to biosorb heavy metals from synthetic wastewater specimens. FTIR, and SEM/XRD analyses were utilized to characterize the microalgal biomass (the adsorbent). The experiments were conducted with several process parameters, including initial solution pH, temperature, and microalgae biomass dose. In order to secure the best experimental conditions, the optimum parameters were estimated using an integrated response surface methodology (RSM), desirability function (DF), and crow search algorithm (CSA) modeling approach. A maximum lead(II) removal efficiency of 99.54% was identified by the RSM–DF platform with the following optimal set of parameters: pH of 6.34, temperature of 27.71 °C, and biomass dosage of 1.5 g L−1. The hybrid RSM–CSA approach provided a globally optimal solution that was similar to the results obtained by the RSM–DF approach. The consistency of the model-predicted optimum conditions was confirmed by conducting experiments under those conditions. It was found that the experimental removal efficiency (97.1%) under optimum conditions was very close (less than a 5% error) to the model-predicted value. The lead(II) biosorption process was better demonstrated by the pseudo-second order kinetic model. Finally, simultaneous removal of metals from wastewater samples containing a mixture of multiple heavy metals was investigated. The removal efficiency of each heavy metal was found to be in the following order: Pb(II) > Co(II) > Cu(II) > Cd(II) > Cr(II).