Removal Of Mn Research Articles

Modification of Multiwalled Carbon Nanotubes and Their Mechanism of Demanganization.

Multiwalled carbon nanotubes (MWCNTs) were modified by oxidation and acidification with concentrated HNO3 and H2SO4, and the modified multiwalled carbon nanotubes (M-MWCNTs) and raw MWCNTs were characterized by several analytical techniques. Then the demanganization effects of MWCNTs and M-MWCNTs were well investigated and elucidated. The experimental data demonstrated that the adsorption efficiency of Mn(II) could be greatly promoted by M-MWCNTs from about 20% to 75%, and the optimal adsorption time was 6 h and the optimal pH was 6. The results of the kinetic model studies showed that Mn(II) removal by M-MWCNTs followed the pseudo-second-order model. Isothermal studies were conducted and the results demonstrated that the experimental data fitted well with the three models. The reliability of the experimental results was well verified by PSO-BP simulation, and the present conclusion could be used as a condition for further simulation. The research results provide a potential technology for promoting the removal of manganese from wastewater; at the same time, the application of various mathematical models also provides more scientific ideas for the research of the mechanism of adsorption of heavy metals by nanomaterials.

Removing Mn, Cu and Fe from Real Wastewaters with Macrophytes: Reviewing the Relationship between Environmental Factors and Plants' Uptake Capacity.

Heavy metal pollution creates environmental health concerns. Among these, iron (Fe), copper (Cu) and manganese (Mn) are commonly found in aquatic environments due to the release of wastewaters. Phytoremediation in hydroponics uses macrophytes to treat contaminated environments, and this is influenced by environmental factors. However, the relationship between these factors and the removal of Fe, Cu and Mn by macrophytes is not known. Therefore, a meta-analysis serves to determine the correlations between environmental factors and the removal of these metals in real wastewater by macrophytes, as well as to identify the role of different aquatic forms of macrophytes in phytoremediation. Emergent macrophytes had higher concentrations of manganese in their tissues, and higher bioconcentrations factor of iron and manganese than floating plants. Regardless of the biotope, higher concentrations of Fe and Cu decreased the ability of plants to bioconcentrate them. The correlations among exposure time, pH, dissolved oxygen, nitrogen, phosphorus, photoperiod and metal phytoremediation by plants were also found. It can be concluded that the emergent macrophytes showed better performance in terms of the removal of Fe, Cu and Mn, and that the significant correlations between environmental factors and removal vary with the type of metal and the environmental factor analyzed.

Experimental study on solidification and remediation of lead–zinc tailings based on microbially induced calcium carbonate precipitation (MICP)

With the development of industry, the human demand for lead and zinc is increasing gradually, and the heavy metal pollution caused by the mining process of lead–zinc tailings is becoming more and more serious. To alleviate the pollution problem, microbially induced calcium carbonate precipitation (MICP) technology has been used to solidify and remedy lead–zinc tailings containing heavy metals based on the multi-shell curing method. Based on unconfined compression strength (UCS) and the parameters of heavy metal ions leaching concentration, exploring the addition of lead–zinc tailings on the impact of microbially induced calcium carbonate precipitation on solidifying and repairing lead–zinc tailings, using SEM, XRD, FTIR, EDS and XPS tests, and revealing the mechanism of MICP to solidify lead–zinc tailings. The results of the experiment showed that MICP had a good solidifying and repairing effect on heavy metals in lead–zinc tailings. When the thickness of lead–zinc tailings was 2 cm, the unconfined compression strength of the specimen was the maximum up to 0.93 MPa and the calcium carbonate content was up to 7.41 %. At the same time, Fe3+, Zn2+, Pb2+, Cu2+ and Cd2+ in the leaching solution could be completely removed, and the removal of Mn2+ and Cr3+was up to 98.24 % and 95.56 % respectively, which was the best condition for solidification. The samples of lead–zinc tailings being solidified and repaired based on MICP showed that calcium carbonate was primarily precipitated as the commonly crystal forms of aragonite, calcite, and vaterite, with strong cohesiveness, which made lead–zinc tailings particles connected together. At the same time, the CO32– and alkaline substances produced by microbial metabolism made the heavy metal ions released by the lead–zinc tailings mainly precipitate in the form of metal carbonate, which reduced the pollution to the environment. This technology provides a new method for solidifying and repairing lead–zinc tailings.

Novel Sustainable Adsorbents Prepared by Banana/Pomegranate Peels via EDTA Grafting for Effective Removal of Cd(II), Co(II), Mn(II), and Ni(II) from Sewage System

Novel Sustainable Adsorbents Prepared by Banana/Pomegranate Peels via EDTA Grafting for Effective Removal of Cd(II), Co(II), Mn(II), and Ni(II) from Sewage System

Thermodynamics of Formation of Al<sub>6</sub>Mn Inter-Metallic Compound for Mn Removal from Molten Al–Mg Alloy

Thermodynamics of Formation of Al<sub>6</sub>Mn Inter-Metallic Compound for Mn Removal from Molten Al–Mg Alloy

Study of reverse osmosis performance for manganese and iron removal from raw freshwater

The presence of metallic ions in raw freshwater is a problem that occurs with greater intensity in periods of drought, due to the intensification of water withdrawal from lower levels of the dams, where there is a higher percentage of organic matter and concentration of metallic ions, including manganese and iron. High levels of these dissolved metals, in addition to altering the organoleptic properties of water, also cause deleterious effects on human and animal health. Given this, the present study aimed to evaluate the use of reverse osmosis in the removal of Mn+2 and Fe+2 from raw freshwater, to comply with the MS 5/2017 regulation (Brazilian standard), which establishes the maximum allowable values for Mn+2 and Fe+2 ions in drinking water. Three synthetic feed solutions were evaluated to study the retention alone and together of the metals, as well as the water permeability before and after the retention tests with each studied solution. The results showed that the reverse osmosis process retained 99 % of Mn+2, 93 % of Fe+2, and 98 % of the two ions together. Regarding the cleaning process, it increased the water permeability of the membrane after exposure to Fe+2 and the mixture of Mn+2 and Fe+2, being reduced after exposure to Mn+2 only. For the three types of feed, the post-cleaning fouling was estimated at 9.14 − 13.65 % in terms of permeability. Thus, reverse osmosis can be considered a promising process for the treatment of drinking water, and further studies are needed to implement this process in water treatment plants.

Effect of Particle Size on Chromium (III) and Manganese (IV) Removal from Tannery Wastewater

The removal of Cr (III) and Mn (IV) from a tannery wastewater was evaluated using atomic absorption spectrophotometer (AAS). Activated carbon prepared from sorghum (bicolor) chaff was used to remove Cr (III) and Mn (IV). The evaluated physicochemical properties of the activated carbon were pH (6.30), bulk density (0.33 g/cm3), moisture content (4.40%), Iodine Adsorption Ratio (0.28 mol/g), porosity (13.00), attrition factor (11.00%), and surface area (797.4 m2/g). Optimum percentage adsorption and equilibrium adsorption capacity for the effect of pH, inlet flow rate, bed height, inlet concentration and particle size gave, (89.796, 90.116, 93.046) % and (2.245, 2.253, 2.326) mg/g, (74.720, 84.990, 91.346) % and (2.277, 2.275, 2.284) mg/g, (88.192, 89.994, 90.190) % and (2.205, 2.249, 2.255) mg/g, (88.934, 90.002, 90.634) % and (2.223, 2.250, 1.266) mg/g, (91.346, 89.964, 88.936) % and (2.284, 2.249, 2.223) mg/g for Cr (III) and (84.630, 87.830, 82.507) % and (1.269, 1.317, 1.238) mg/g, (47.770, 74.425,83.790) % and (0.239, 0.744, 1.257) mg/g, (85.590, 84.023, 83.167) % and (1.284, 1.260, 1.248) mg/g, (82.473, 83.790, 85.230 ) % and (1.237, 1.257, 1.278) mg/g, (88.497, 87.220, 84.420) % and (1.327, 1.308, 1.266) mg/g for Mn (1V) respectively. The results therefore, shows that percentage adsorption increases with the effects mentioned and the kinetic data fitted well to the model for the effect of particle size.

Mechanism of Permanganate Biosorption by Fermentation Biowaste

Biosorptive treatment of industrial wastewater contaminated with heavy metals has been recognized as one of the most effective green tools, competing with traditional physical/chemical treatment processes. This study delves into the detailed investigation of the biosorbent prepared from fermentation biowaste, particularly focusing on the mechanism behind permanganate (Mn(VII)) removal. Various parameters including pH, biosorbent dosage, initial concentration, and temperature were examined. Among these factors, solution pH emerged as the most crucial in removing Mn(VII) using the biosorbent. The significant removal of Mn(VII) was attributed to both reduction and adsorption, as confirmed by X-ray photoelectron spectroscopy. Depending on the experimental conditions, the removal of Mn(VII) was influenced not only by simple adsorption but also by oxidation-reduction and precipitation processes. This study not only advances our understanding of biosorptive treatment but also highlights the promising potential of fermentation biowaste-based biosorbents for effective Mn(VII) removal.

The batch tests on new catalytic filtration masses creation by natural materials modification with MnO2 supporting by electrolysis with the view of Fe and Mn removal

The batch tests on new catalytic filtration masses creation by natural materials modification with MnO2 supporting by electrolysis with the view of Fe and Mn removal

A comparative analysis on Mn (VII) removal from wastewater using leaves of Dalbergia sissoo and Brassica campestris by biosorption method

A comparative analysis on Mn (VII) removal from wastewater using leaves of Dalbergia sissoo and Brassica campestris by biosorption method

Adsorption removal of Mn2+ and NH4+–N from electrolytic manganese metal wastewater by modified phosphate ore flotation tailings

Electrolytic metal manganese wastewater (EMMW) is industrial wastewater produced in the process of producing electrolytic metal manganese, which contains Mn2+ and NH4+–N pollutants.

Acceleration of sand filtration start-up for manganese-containing groundwater treatment: microbial-mediated autocatalytic oxidation of manganese oxides

Mn removal performance in biotic and abiotic accelerated rapid sand filters.

EVALUATION OF THE EFFICIENCY OF SORBENTS-CATALYSTS FOR THE PURIFICATION OF WATER FROM MANGANESE COMPOUNDS

The condition of sources and central water supply systems does not guarantee the required quality of drinking water. A large part of the population of Ukraine uses drinking water that does not meet hygienic requirements according to various indicators. Manganese compounds are quite often present in natural waters. Their quantitative content can vary in a wide range, depending on the region, it can be 5-6 mg/dm3. Manganese in underground waters is presented as ion Mn2+, salts of which are soluble. To remove manganese from water one should transfer it to insoluble state by oxidation. Today, there are a number of typical technologies of demagnetization of water. Many works have also been published which describe the purification of water from manganese ion. It is worth noting that with a high content of manganese compounds in water, their removal is a rather difficult task. Removal of manganese compounds from water can be implemented using the ion exchange method, which consists of filtering water through loading in salt or acidic form. At the same time, softening and desalination of water can occur simultaneously. Therefore, the ion exchange method should be used for comprehensive water purification, softening, and removal of manganese compounds. In order to study the oxidizing capacity of catalytic loading with respect to manganese compounds in water were used as a catalytic load KU-2-8 cationite modified with magnetite and manganese oxide in H+, Na+, and Ca2+ forms. To modify cationite with magnetite under static conditions, it was treated with a solution containing a mixture of Fe2+ and Fe3+ ions in a ratio of 1:2. The research was also carried out on the preparation of catalysts based on cationites by modifying them with manganese compounds. The purpose of this article is to evaluate the efficiency of manganese removal from water when using a catalyst sorbent. The article presents the results of research on water purification from manganese compounds using sorbents-catalysts modified with iron and manganese compounds. It was established that in static and dynamic conditions, complete extraction of manganese ions can be achieved using sorbents based on polymer resin and magnetite. When using cation exchange resin modified with magnetite, the removal of Mn2+ ions from aqueous solutions occurs both due to ion exchange, regardless of the form of the ion exchanger, and due to oxidation on the catalyst (magnetite) in the presence of dissolved oxygen. Modified cation exchange resin in Na+ form leads to the extraction of manganese due to sorption and oxidation of Mn2+. In this case, sorption of calcium and magnesium ions, which is known to be accompanied by an increase in pH. The pH of the medium increased, which increased the efficiency of oxidation of manganese ions on magnetite. Under these conditions, the sorbent catalyst provides complete removal of manganese ions due to catalytic oxidation and sorption of manganese ions on magnetite.

Removal of manganese from water by modified groundwater plant sludge: Mechanism and application as filter media

Manganese (Mn(II)) is a common contaminant in groundwater, resulting in substantial manganese oxides (MnOx) in groundwater treatment sludge (GTS). In this study, GTS was recycled to fabricate the alkali-modified GTS (AGTS). The kinetics and thermodynamics of Mn(II) removal and the efficiency of continuous Mn(II) removal by AGTS-coated filter media were studied. The pseudo-second-order kinetics and the Langmuir isotherm models effectively described the removal behavior. The maximum removal capacity obtained from the Langmuir isotherm model was 26.39 mg/g. The column experiment results showed that the removal of Mn(II) (10 mg/L) by the AGTS-coated filter media first goes through the initial adsorption and penetration process, followed by the development of the catalytic oxidation ability, finally realizing the continuous removal of 99.98 % Mn(II). The column experiment achieved up to 120.51 mg/g Mn(II) removal capacity by the Thomas model, and the catalytic oxidation rate constant is 0.0140 min−1. The characterization of the sludge particles revealed that AGTS had a rougher surface and massive oxygen-containing functional groups. Through the electrical state, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) analyses, it was elucidated that the AGTS initially binds Mn(II) ions by adsorption and then oxidizes them into a new MnOx layer to remove Mn(II) by long-term catalytic oxidation. The treated water was reliable, and nearly no hazardous compounds were released. This study provides a promising approach for recycling waste GTS and fabricating Mn(II) removal filter media.

Potensi Bacillus cereus dan Bacillus subtilis Menurunkan Kandungan Logam Fe dan Mn pada Air Asam Tambang

Acid mine drainage (AMD) with pH 2,56, also high concentration of Fe and Mn respectively 35 mg/L and 8,83 mg/L should be treated to prevent the pollution. AMD treatment can be done by adding bacteria. Bacillus cereus and Bacillus subtilis isolated from AMD sample using selective media agar. Each bacteria was added 5% and 10% to the 200 mL AMD sample separately. The result shows that the highest removal of Fe and Mn in AMD was 62.03% and 18.02% with 10% B. cereus. Meanwhile, with addition 5% B.subtilis shows the highest Fe and Mn removal respectively 41.91% and 16.79%. Therefore, these bacteria have potential to decrease Fe and Mn concentrations in AMD.

Development of rice straw biochar through pyrolysis to improve drinking water quality in arsenic and manganese contaminated areas

Heavy metal pollution in groundwater is a significant concern for human health in the Indo-Gangetic Plain of India. Moreover, due to a lack of economically feasible options for rice straw utilization, around 84 Mt of rice straw was burned on the field in India. We aim to transform rice straw waste into biochar and utilize it for heavy metal removal from groundwater. Therefore, in this study, biochar was produced from rice straw at different temperatures (400–600 °C) through pyrolysis, and it was applied to remove manganese (Mn) and arsenic (As) from the field and synthetic water. Biochar derived at 600 °C had a higher surface area (78.17 m2 g−1) and adsorption capacity for As (4.51 mg g−1) and Mn (3.61 mg g−1) in a binary metal system. The pseudo-second order kinetics (R2>0.97) and Langmuir isotherms (R2>0.94) model batter explained the adsorption of As and Mn. The adsorption was facilitated by electrostatic attraction between metalloids and oxygenated (-COOH and -O.H.) surface functional groups. Health risk assessment indicated that field water (50 ml) treated with 0.1 g biochar had the highest As and Mn removal efficiency (>85%) and hence lowered the cancer risk in the community. The cost of 1 kg RS600 biochar production (0.913 U.S. $) is comparable with other adsorbents.

Performance evaluation and life cycle assessment of electrocoagulation process for manganese removal from wastewater using titanium electrodes

Excess manganese (Mn) concentrations can pose environmental and health risks. Currently, research on Mn removal by electrocoagulation (EC) using transition metal electrodes and the determination of its potential environmental impacts is limited. This study aims to assess the electrocoagulation process's performance with a titanium electrode as a sacrificial anode while also performing a life cycle assessment (LCA) of the process. The initial pH, current density (CD), electrode spacings, electrolyte types, concentrations, and electrode arrangement were all examined. For synthetic wastewater, most of the experiments used a concentration of Mn of 2 mg/L and sodium chloride as a supporting electrolyte at a concentration of 1 g/L. LCA software (OpenLCA 1.11) was used to assess the potential environmental impacts. Optimal operating conditions within the experimental range were as follows: initial pH = 7, CD = 10 mA/cm2, gap distance = 2 cm, and 1 g/L NaCl. Under these conditions, the maximum Mn removal efficiency was 96.5% after 60 min. There was an improvement of 2% rise after 60 min when the temperature increased from 20 °C to 40 °C. For real wastewater, the highest removal efficiencies for Mn and chemical oxygen demand after 60 min were 91.3% and 92%, respectively. The pseudo second order model provides the highest coefficient of determination for expressing the experimental data. Global warming, human non-carcinogenic toxicity, and terrestrial ecotoxicity were the most important categories of impact examined in this work according to the LCA (0.00064 kg CO2 eq, 0.00018 kg 1,4-DCB, and 0.00028 kg 1,4-DCB, respectively). To effectively remove Mn using EC with Ti electrodes, it appears that a period of electrolysis of 10 min would be sufficient under most of the conditions investigated in this study. The reduction in the electrolysis time will lead to a reduction in the operating costs of the system.

Manganese Removal from Acid Mine Drainage by a Consortium of Mn-Oxidizing Bacteria in Continuous Stirred Tank Bioreactor: Long-Term Treatment and Reactive Mixture Characterization

Biological treatments based on Mn-oxidizing bacteria can effectively remove Mn from contaminated water. However, the mechanisms and key organisms of biological low-pH Mn(II) removal are largely unexplored. In this study, bioremediation based on an enriched consortium of acid-resistant Mn-oxidizing bacteria for Mn-rich acid mine drainage (AMD) was evaluated in a continuous stirred tank bioreactor (CSTB), and the removal mechanism of Mn(II) was further studied. The highest removal rate of 33.2 ± 1.8 mg/L/d and maximum removal efficiency of 82.4 ± 1.8% were achieved with a pH of 5.5, hydraulic retention time (HRT) of 48 h, chemical oxygen demand (COD) concentration of 2000.0 mg/L, and Mn concentration of 80.0 mg/L, respectively. The Mn oxidation rate was ∼4.1 μM/h in the continuous stirred tank bioreactor (CSTB) under stable conditions. Acinetobacter and Azospirillum were the main contributors for Mn oxidation in the bioreactor. X-ray diffraction (XRD) analysis suggested that Mn removal proceeds via the formation of biogenic precipitates consisting of MnO2, MnOOH, and MnCO3. The performance of the CSTB was further evaluated by actual Mn-rich acid mine drainage, and Mn, Cu, Zn, and Cd removal efficiencies were 86.5 ± 2.4%, 98.8 ± 2.2%, and 96.9 ± 1.0%, and 97.0 ± 1.7%, respectively. Results from this work have demonstrated that Mn-oxidizing bacteria can be effective at processing complex Mn-rich acid mine drainage.

The role of chloramines in enhancing soluble manganese removal by manganese contactors by W.R. Knocke, A.M. Weber, P.H. Hargette and E. Odom

Abstract Manganese (Mn) contactors have previously been shown to be quite effective in removing dissolved Mn from drinking water. To date, the contactor media have been regenerated by the application of free chlorine, either continuously in the contactor-applied water or via offline regeneration. This research study was the first to evaluate the potential role of chloramines for the online regeneration of MnOx(s)-coated contactor media. Testing initially at the bench scale and then subsequently over 6 months at the pilot scale demonstrated that chloramines were quite effective at promoting significant media regeneration. Pilot-scale data showed that the presence of chloramines addressed approximately 80% of the media regeneration requirements, allowing for the addition of free chlorine following media backwashing to address the remaining oxidant needs for media regeneration. Hydraulic loading rates of up to 39 m/hr (16 gpm/ft2) could be employed and still produce highly effective Mn removal. The means by which these research results can be applied to other water treatment situations are also discussed.

Solvent extraction of cobalt from spent lithium-ion batteries: Dynamic optimization of the number of extraction stages using factorial design of experiments and response surface methodology

The optimization of lithium-ion batteries (LiBs) recycling is crucial not only from a waste management perspective but also to decrease the dependence on imports of critical raw materials. In addition, the diversification of the recycling technologies is very important for better flexibility of the market. This study aims at investigating the recovery of Co from spent LiBs using solvent extraction from a real chloride-based solution obtained after the removal of Mn, which is very rarely reported. Cyanex 272 was used as the extractant and the effect of several variables on the extraction efficiency was considered to model and optimize the separation of Co and Ni. The number of extraction stages directly affects not only the process efficiency but also its cost. Thus, in this work, a novel approach was developed to assist in the selection of the number of extraction stages using a dynamic method based on the factorial design of experiments and response surface methodology combined with the Kremseŕs Equation. This method can assist the process design, decrease the overall cost of the operation, and optimize the separation of Co and Ni in a reduced number of extraction stages. The concentration of Co and Ni in the feed solutions is ∼ 8.3 g/L and 1.9 g/L, respectively. Based on the results, 98% extraction efficiency for Co can be achieved in 1 to 2 extraction stages with low co-extraction of Ni (<5%) when using 0.6–0.8 M Cyanex 272, O:A ratio below 1 and pH ∼ 5, but several combinations of conditions could provide similar results.