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The present study investigates the efficacy of newly developed Zr-based metal–organic frameworks, specifically MIP-206, and its amine-modified counterpart, MIP-206-NH2, for the re-covery of antimony (Sb) from both synthetic and actual mining wastewater. Batch method studies were employed to examine the effect of waste media pH, Sb concentration, process kinetics, and the performance of the regeneration solution. MIP-206-NH2 exhibited impressive separation capabilities, achieving 102.18 mg/g and 63.23 mg/g for Sb (V) and Sb (III), respectively. In contrast, the pristine MIP-206 reached maximum values of 26.26 mg/g for Sb (V) and 16.95 mg/g for Sb (III). The separation process was well-described by the Langmuir equation, and the kinetics followed the pseudo-second-order model. Although the amine modification resulted in a decrease in the surface area of MIP-206 from 1345.21 to 1169.86 m2/g, SEM and XRD analyses confirmed that the structural integrity of MIP-206-NH2 remained unchanged. In terms of reusability, MIP-206-NH2 maintained up to 90% of its separation performance over 9 cycles, while MIP-206 demonstrated effectiveness for 7 cycles. The regeneration solution exhibited a capacity of approximately 0.63 mol/L for Sb (V) and 0.71 mol/L for Sb (III). Furthermore, MIP-206 and MIP-206-NH2 demonstrated successful application in selectively separating Sb from real mining wastewater. [ABSTRACT FROM AUTHOR]

Abstract The present study investigates the efficacy of newly developed Zr-based metal–organic frameworks, specifically MIP-206, and its amine-modified counterpart, MIP-206-NH2, for the re-covery of antimony (Sb) from both synthetic and actual mining wastewater. Batch method studies were employed to examine the effect of waste media pH, Sb concentration, process kinetics, and the performance of the regeneration solution. MIP-206-NH2 exhibited impressive separation capabilities, achieving 102.18 mg/g and 63.23 mg/g for Sb (V) and Sb (III), respectively. In contrast, the pristine MIP-206 reached maximum values of 26.26 mg/g for Sb (V) and 16.95 mg/g for Sb (III). The separation process was well-described by the Langmuir equation, and the kinetics followed the pseudo-second-order model. Although the amine modification resulted in a decrease in the surface area of MIP-206 from 1345.21 to 1169.86 m2/g, SEM and XRD analyses confirmed that the structural integrity of MIP-206-NH2 remained unchanged. In terms of reusability, MIP-206-NH2 maintained up to 90% of its separation performance over 9 cycles, while MIP-206 demonstrated effectiveness for 7 cycles. The regeneration solution exhibited a capacity of approximately 0.63 mol/L for Sb (V) and 0.71 mol/L for Sb (III). Furthermore, MIP-206 and MIP-206-NH2 demonstrated successful application in selectively separating Sb from real mining wastewater.

Mining wastewater is air that comes from coal mining activities which include transporting, transporting and stockpiling both in open pit mines and underground mines which can cause the formation of air processing sludge or sludge and acid mine air. At PT. PT. Marunda Grahamineral mine waste water comes from the mining area, including from the ROM, and flows into a settling pond which then flows into the river around the mining area. Mining wastewater in the SP 14 SE pit CTM settling pool has a pH of 5 and a high TSS value of 9,460 mg/l. In this research, quicklime and zeolite were added at doses of 0.1 gr/l, 0.5 gr/l and 0.8 gr/l with the aim of improving the quality of mine wastewater. After experiments were carried out by adding quicklime and zeolite, the quality of mine wastewater met environmental quality standards. However, the reactivity of quicklime is greater than zeolite in improving the quality of mine wastewater. This can be seen from the increase in pH and decrease in Mn content levels. Where with an effective dose of 0.1 gr/l quicklime the pH value which was initially 5 increased to 7.7 and the Mn content which was initially 0.03 mg/l decreased to 0.00 mg/l. [ABSTRACT FROM AUTHOR]

Synthesis of Ag2O-TiO2-kaolinite clay nanocomposite was undertaken to eliminate some selected heavy metals released into the environment from mining wastewater. Silver nitrate and titanium-tetra-isopropoxide were employed as the bulk reagents for the Ag2O-TiO2 nanoparticles synthesis, using an aqueous extract of Parkia biglobossa leaf (green synthesis method). The Ag2O-TiO2 nanoparticles were supported on acid-activated kaolinite clay via wet impregnation method, to develop the nanocomposite and were characterized for phase structure, morphology, and oxidation states. The functionality of the nanocomposite for the sequestration of Mn2+, Fe3+, Cu2+, and Pb2+ ions from mining wastewater was examined by adsorption studies. The XRD pattern of the Ag2O-TiO2-kaolinite clay reveals the synthesis of the rutile phase of TiO2 embedded in the kaolinite clay. While the HRSEM shows an evenly distributed arrangement of hemispherical stacks of kaolinites. The oxidation states of Ag2O and TiO2 revealed by the XPS are + 1 and + 4 respectively either as binary or ternary nanocomposite. The Ag2O-TiO2-clay nanocomposite adsorbed 99.85%, 97.85% 95.18%, and 40% of Mn2+, Fe3+, Cu2+, and Pb2+ ions at 120 min from the mining wastewater respectively. The synergetic efforts of the Ag2O-TiO2-clay were responsible for the adsorptive capability of the nanocomposite for the removal of the selected heavy metal ions. [ABSTRACT FROM AUTHOR]

Mining wastewater can have adverse effects on the ecosystem; thus, treatment before discharging into the environment is of utmost importance. This manuscript reports on the effect of mining wastewater on the environment. Moreover, the currently used, effective and commercialised mine wastewater treatment technologies such as SAVMIN®, SPARRO®, Biogenic sulphide, and DESALX® are reported in this study. These technologies integrate two or more separation processes, which have been proven to be effective for the high recovery of salts and water for reuse. Some of the technologies reported can significantly recover salts and >95% of water. Modern pilot-stage and laboratory-scale treatment systems used for the recovery and removal of metals are also reported herein. Since some treatment technologies can generate highly toxic sludge and other waste products, the management of the generated waste was also considered. Some studies have focused on the treatment of wastewater at the laboratory level using the adsorption process. Most adsorbents exhibit promising results; however, there is insufficient research on reusability, toxic sludge management, and the economic analysis of the systems. Moreover, the implementation of adsorption systems in wastewater is necessary. Furthermore, the integration of treatment systems to recover precious metals at low concentrations is desirable in addition to water reclamation to achieve circular mine water.

Mining wastewater (MWW) can contain mercury in high concentrations. In this study, four autochthonous aquatic plant species (Eichhornia Crassipes—EC, Marsilea Quadrifolia—MQ, Ludwigia Helminthorrhiza—LH, and Lemna Minor—LM) were identified and tested for phytoaccumulation of total mercury (THg). To better study the accumulation phenomenon and macrophyte responses, this work has been divided into three phases, and pilot-scale reactors have been used to simulate real conditions. The results highlighted that, in case of 15 µgTHg,fed, the bioconcentration factor (BCF) was significantly higher in EC (19.04) and LH (18.41) with respect to MQ and LM (almost six times and two times higher, respectively). EC granted the best results in terms of THg accumulation (50.90%) and lower evapotranspiration of THg phenomenon with respect to LH. A significant decrease of the BCF (from 23.45 to 21.98) and an increase of the TF (from 0.23 up to 0.73) after 42 d highlighted that a breaking-time in terms of THg accumulation was reached due to the deterioration of the roots. In terms of the kinetics of THg removal by bioaccumulation, an HLT of 69.31 d was found, which is more than the breaking-time of the EC system, proving that a periodic replacement of exhausted macrophytes is required to obtain a higher percentage of THg removal.

Mining wastewater (MWW) can contain mercury in high concentrations. In this study, four autochthonous aquatic plant species (Eichhornia Crassipes—EC, Marsilea Quadrifolia—MQ, Ludwigia Helminthorrhiza—LH, and Lemna Minor—LM) were identified and tested for phytoaccumulation of total mercury (THg). To better study the accumulation phenomenon and macrophyte responses, this work has been divided into three phases, and pilot-scale reactors have been used to simulate real conditions. The results highlighted that, in case of 15 µgTHg,fed, the bioconcentration factor (BCF) was significantly higher in EC (19.04) and LH (18.41) with respect to MQ and LM (almost six times and two times higher, respectively). EC granted the best results in terms of THg accumulation (50.90%) and lower evapotranspiration of THg phenomenon with respect to LH. A significant decrease of the BCF (from 23.45 to 21.98) and an increase of the TF (from 0.23 up to 0.73) after 42 d highlighted that a breaking-time in terms of THg accumulation was reached due to the deterioration of the roots. In terms of the kinetics of THg removal by bioaccumulation, an HLT of 69.31 d was found, which is more than the breaking-time of the EC system, proving that a periodic replacement of exhausted macrophytes is required to obtain a higher percentage of THg removal. [ABSTRACT FROM AUTHOR]

An approach to remove ammonia from mining wastewater is to precipitate ammonia into struvite, and flocculation was proved to enhance settling of struvite flocs. But the current literature fails to consider flocculent properties of struvite flocs, and previous studies focused only on small volumes. This study evaluates the effect of ammonia concentration and height on removal efficiency of struvite flocs in a batch system and compares removal efficiency of struvite flocs between a batch and a pilot‐scale continuous settling process to evaluate the potential of using flocculation to recover struvite crystals as a stand‐alone method. Removal efficiency of struvite using flocculation is evaluated depending on depth in a batch system for two different ammonia concentrations (45 and 90 ppm) and in a continuous system for different flowrates. It is shown that a higher concentration promotes flocculation and enhances settling velocities of struvite flocs. The difference between the batch and the continuous processes for the same removal efficiency was significantly higher from what has been reported in the literature: in the continuous process, 89% of struvite flocs have been recovered with a surface overflow rate (SOR) of 1.8 m.h−1, whereas, for the same height, the same efficiency corresponds to SOR = 9 m.h−1 in the batch process. The fragile nature of struvite flocs is potentially responsible for such a difference. Practitioner Points: Settling velocities of struvite flocs are highly dependant on concentration and depth.Removal efficiency are considerably higher with a batch settling process for the same surface overflow rate.Flocculation enable 89% of struvite fines to be recovered in a continuous settling process with a SOR of 1.8 m.hs−1. [ABSTRACT FROM AUTHOR]

One of the challenges of the twenty-first century is related to the discharge and disposal of mine effluents and wastewater resulting from mine dewatering, precipitation, and surface runoff in mines, especially acidic effluents that contain a variety of toxic and heavy metals and are the main sources of surface and groundwater pollution. Various physical, chemical, and biological methods have been developed and used to treat mine effluents. All proposed methods have their own disadvantages that make their use challenging. One of the new methods used for wastewater treatment is the electrical coagulation process, which has attracted the attention of researchers in recent years due to its advantages such as simplicity, environmental friendliness, and low cost. The present review focused on the applications of electrocoagulation for mine wastewater treatment as well as metals recovery. In addition, the main mechanisms, advantages, and weaknesses of electrocoagulation were reviewed. [ABSTRACT FROM AUTHOR]

Mining wastewater (MWw) in tailing ponds is one of the major obstacles in reusing tailings in practice and should be disposed preferentially. This paper investigated the feasibility of exploring MWw from copper mining as a source of mixing water to prepare activators for alkali-activated slag materials (AASM). Four MWws with different concentrations were prepared by using MWw to replace all, 1/2, 1/3, and 1/4 of tap water. The influences of different MWws on the setting time, hydration kinetics, hydration products, compressive strength, nano-mechanical properties, pore structure of AASM were investigated. Experimental results confirmed that MWw can be upcycled as the partial or total mixing water for alkali-activated slag materials. The influence of MWw on the properties of AASM was related to its concentration. MWw with low concentrations accelerated the hydration of slag at early ages, nevertheless raw MWw without dilution slightly impeded the hydration process. Although no new hydration product is induced by adding MWw, both NMR pore analysis and nanoindentation testing suggested that the addition of MWw densified the hydration products, which is beneficial for mechanical properties of AASM. As a result, the 28d compressive strengths of AASM increased with increased concentrations of MWw by − 0.8 to 19.9%. Through this paper, a low-cost, green and practical method was developed as an option for the disposal and recycle of MWw. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • E. coli for REEs enrichment excelled Non-REEs, causing HREEs/LREEs fractionation. • 4 cycles in E. coli prove the stability of REEs recovery from mining wastewater. • REEs recovery mechanisms involves electrostatic attraction, ion exchange. • The economic viability of Ecoli 's recovery is shown by the cost assessment. Microbes used for the recovery of rare earth elements (REEs) from mining wastewater indicated traces of Escherichia coli (E. coli , 2149.6 μg/g), Bacillus sphaericus (1636.6 μg/g), Bacillus mycoides (1469.3 μg/g), and Bacillus cereus (1083.9 μg/g). Of these, E. coli showed an affinity for REEs than non-REEs (Mn and Zn). The amount of heavy REEs adsorbed (1511.1 μg/g) on E. coli was higher than light REEs (638.0 μg/g) due to the process of increasing adsorption with decreasing ionic radius. Additionally, E. coli demonstrated stability in the recovery of REEs from mining wastewater, as evidenced by 4 cycles. SEM-EDS, XPS and FTIR showed that REEs had a disruptive effect on cells, REEs absorbed and desorbed on the cell surface including ion exchange with ions such as Na+, ligand binding with functional groups like –NH 2. Finally, the cost assessment confirmed the economically feasible of E. coli in recovery of REEs from mining wastewater. [ABSTRACT FROM AUTHOR]

While microbial technologies, which are considered to be environmentally friendly, have great potential for the recovery of rare earth elements (REEs) from mining wastewater, their applications have been restricted due to a lack of efficient biosorbents. In this study, a strain of Pseudomonas psychrotolerans isolated from yttrium-enriched mine soil was used to recover yttrium (Y(III)) from rare-earth mining wastewater. At an initial Y(III) dose of 50 mg L−1, the amount of Y(III) adsorbed by P. psychrotolerans reached 99.9 % after 24 h. Various characterization techniques revealed that P. psychrotolerans adsorbed Y(III) mainly through complexation of oxygen-containing functional groups and electrostatic interactions. A high level of adsorption efficiency (>99.9 %) was maintained after five consecutive adsorption/desorption cycles, indicating that P. psychrotolerans was highly reusable. While the efficiency of adsorbing Y(III) by P. psychrotolerans decreased (34.4 %) in actual rare earth mining wastewater, selectivity toward other REEs (≤ 18.4 %) was still observed. Consequently, this study provides a promising green, environmentally friendly and sustainable microbial approach for the selective recovery of REEs from rare earth wastewater. [Display omitted] • P. psychrotolerans isolated from mining soil selectively recovered yttrium from wastewater. • P. psychrotolerans removed 99.9 % of 50 mg L−1 yttrium. • Recovery of yttrium involved electrostatic adsorption, surface complexation and EPS. • P. psychrotolerans was a potential practical biosorbent for rare earth element recovery. [ABSTRACT FROM AUTHOR]

This study presents the inaugural demonstration of a microbial electrochemical cell (MXC)-based biosensor for naphthenic acids (NAs) detection in oil sands process water (OSPW) from a mining site. During the calibration process, different operating parameters were evaluated, including standing times (3 – 12 hours) and charging durations (5 – 20 minutes) within the charging-discharging cycles. The observations ascertained that a combination of a 12-hour standing period followed by a 15-minute charging period yielded the optimal current output when measuring NA concentrations ranging from 4.98 to 24.9 mg/L in real OSPW samples (diluted to concentrations of 20–100 %). Subsequently, incorporating diverse inoculum sources from MXCs led to significant signal output improvements, with one sustained on a mixture of cyclohexane carboxylic acids, commercial naphthenic acids, and real OSPW, and another exposed to acetate medium for over four years. Moreover, integrating quorum sensing (QS) autoinducers (10 μM) increased the current generation, highlighting the potential for more sensitive detection capabilities. Ultimately, our MXC biosensor could enable a cost-effective and rapid detection of OSPW NAs, offering a potential alternative for environmental surveillance. [Display omitted] • Microbial electrochemical biosensor demonstrated for detecting NAs in real OSPW. • 12-h standing/15-min charging times were the best calibration method for biosensor. • Acetate-fed reactor effluent as an inoculum greatly boosted the current output. • Exogenous QS autoinducer (C6-HSL) further increased the biosensor's sensitivity. [ABSTRACT FROM AUTHOR]

Climate change and related issues such as water scarcity and the urgent need for a transition to sustainable energy sources have motivated the development of novel processes and techniques that can be applied for water treatment, recovery and reuse. Among these emerging processes, membrane distillation in its different configurations has been extensively studied and reported in the literature. A bibliometric analysis was performed to investigate the research documents published in the scientific database Scopus until 2024, related to use of membrane distillation for water recovery and reuse. The main quantitative attributes of the research during this period were identified. The results of this analysis showed a very low scientific production until 2005, followed by a rapid exponential increase since then. The combined contribution of the two most productive countries (China and USA respectively) accounted for more than 41 % of the total number of publications, followed by Australia and Saudi Arabia, which occupied the third and fourth positions in the ranking. Chemical engineering was the most important subject category (57.4 % contribution), closely followed by environmental sciences. The review of the most cited documents and keywords showed that membrane wetting is one of the main drawbacks that can reduce the performance of membrane distillation and the use of innovative superhydrophobic, omniphobic or Janus membranes resulted an adequate solution to avoid this problem. Moreover, the desalination of seawater, brines and other highly saline solutions can be considered as the most studied application of membrane distillation. The consideration of the energetic aspects of membrane distillation and its coupling with other technologies were identified as relevant topics during the bibliometric network analysis. Special attention was given to the potential of membrane distillation for water recovery and reuse in the Chilean context of water stress for the production of drinking water and the treatment of domestic greywater and wastewater from mining and other industrial activities. • A bibliometric analysis of membrane distillation potential to recover water to be reused • Exponential growth of the research in this topic (led by China, USA and Australia) • Membrane wetting as the main drawback, which can be minimized using innovative membranes • Energy aspects are critical, promoting the use of waste heat and renewable energy sources • Potential to treat greywater and wastewater from mining activities and other industrial sectors [ABSTRACT FROM AUTHOR]

Arthrospira platensis has very high absorption by photosynthesis processes of CO2 fixation and release of oxygen. It was becoming significant microalgae for biological wastewater treatment because of their bodies' accumulation of nutrients, heavy metals, organic and inorganic compounds used as the main source of their life production in wastewater. The objective of this study was to determine the ability of Arthrospira platensis for bioremediation by biosorption of heavy metals present in mining wastewater. Microalgae culture condition parameters were: temperature fixed at 30°C-35°C; the light was 1,000-2,000 lux set for 12 h d-1 and 12 h night-1; pH; turbidity was 25-40 NTU. Biosorption was influenced by sorbent concentration (5-60 g L-1), pH 2.0-9.0, and contact time (60 min) for heavy metals removal. It was related to nutrients consumption from wastewater with microalgae growth production by biosorption and takes place with separation of micronutrients (Zn, Cu, and Fe) and toxic metal such (Pb) from microalgae samples in a solution using centrifugation. The photosynthesis process was very suitable, that why chlorophyll productivity was very high. At low light intensity (1,000-1,400 lux), Arthrospira platensis consumed a high amount of nutrients (COD, TP, TN, ammonium) for growth. At high light intensity (2,000 lux), cell productivity, biomass productivity, growth rate, protein content, and energy value were very high. The effect of biosorbent on heavy metals removal from wastewater provides the following results: zinc adsorbed decreased from 4.08 to 2.1216 mg g-1; iron from 6.03 to 0.6 mg g-1; copper from 5.02 to 0.75 mg g-1; and lead decreased from 7.04 to 0.98 mg g-1. The effect of pH on metals biosorption was: sulfates (SO4) 93%, iron Fe 99%, lead Pb 95%, zinc Zn 52%, copper Cu 94%) removal efficiency with pH above 7.1. Heavy metals biosorption from wastewater was depended on sorbent concentration, pH, and contact time. The presence of multi-metal in culture systems decreases zinc adsorption, compared to the single metal one. The previous study was Arthrospira platensis biomass removed 50% of zinc from wastewater, which means that higher concentrations of other metal ions present in the wastewater don't affect the removal of zinc ions from the wastewater. The removal of zinc ions from the mining wastewater was about 52% in the current study. [ABSTRACT FROM AUTHOR]

The use of amalgamation process to recover gold from mined ores by the small-scale gold miners in the Philippines and other developing countries produces and dispose of untreated wastewater to the receiving water bodies. In this study, a field-scale filter bed system was constructed to treat heavy metal metal-laden wastewater collected from small-scale gold mining site in Paracale, Camarines Norte, Philippines. The filter bed system was consists of sedimentation tank and filter bed with Cocopeat, a by-product of coconut husk, as adsorbent. Physico-chemical parameters (temperature, pH, oxidation-reduction potential, electrical conductivity, turbidity, dissolved oxygen, total dissolved solids, salinity, total suspended solids, color) and heavy metal (As, Ba, Cd, Hg, Pb) concentrations were monitored during the 50 days experiment at a flow rate of 40 Liter per hour for 3 hours daily wastewater application. Significant reduction was achieved on heavy metals; As (97.11%), Ba (39.75%), Cd (74.24%), Hg (97.02%), Pb (98.82%) from small-scale gold mining (SSGM)wastewater in sedimentation phase and further reductions on As (1.39%), Ba (28.00%), Cd (4.95%), Hg (2.91%), Pb (0.97%) were achieved by adsorption in the Cocopeat filter bed. Measured effluent physico-chemical parameters and heavy metal concentrations were within the respective regulatory limits. Other effluent parameters with strong correlation with total suspended solids such as turbidity and color, though not regulated, were reduced significantly. All adsorbed heavy metals accumulated in the upper 25 cm of the Cocopeat column in the filter bed. Measured heavy metal concentrations in Cocopeat suggest that the adsorbent was not saturated and further application of small-scale gold mining wastewater is recommended to determine its useful life.

In this study, a sample of 2-methylimidazole zinc salt (ZIF-8) demonstrated high selectivity for the recovery of heavy rare earth elements (REEs) from real rare earth mining wastewater. Results show that the distribution coefficient values of Y 3+ (4.02 × 10 4 mL·g -1 ), Gd 3+ (7.8 × 10 4 mL·g -1 ), and Dy 3+ (6.8 × 10 4 mL·g -1 ) are orders of magnitude higher than those of K + (359.51 mL·g -1 ), Mn 2+ (266.67 mL·g -1 ), Ca 2+ (396.42 mL·g -1 ), and Mg 2+ (239.48 mL·g -1 ). Moreover, the desorption efficiency of heavy REEs exceeded 40%. Advanced characterizations and density functional theory (DFT) calculations were utilized to elucidate that the heavy REEs were more likely to bind to the nitrogen atoms of imidazole groups on ZIF-8 compared to non-REEs. Furthermore, the adsorption and desorption of heavy REEs primarily depend on the chemical interaction confirmed by adsorption kinetics, isotherm model, and thermodynamic analysis, which involves the dissociation of water and the formation of REE-O bonds. Finally, the ZIF-8 exhibits a remarkable recovery efficiency of over 40% for heavy REEs in column tests conducted over 7h. The findings reported here provide new insights into the selective recovery of heavy REEs from real mining wastewater.

• Iron sulfide nanoparticles was biosynthesized by Pinus massoniana Lamb. • nFeS showed a highly selectively recover Y(Ⅲ) from mining wastewater. • The adsorption of Y(Ⅲ) was predominant by the capping layer. • The result showed that effective desorption of Y(Ⅲ) from mining wastewater. The selective recovery of rare earth elements (REEs) from mining wastewater has become a hot research topic due to the increasing industrial value of REEs. Herein, biosynthetic iron sulfide nanoparticles (nFeS) were deployed as a superior adsorbent to selectively recover Y(Ⅲ) from mining wastewater. The maximum adsorption efficiency achieved for of Y(Ⅲ) by nFeS was 81.2 % compared to only 38.7 % for Eu(Ⅲ) and 20.8 % for Mn(Ⅱ), demonstrating that nFeS had a high selective adsorption for Y(Ⅲ). To understand the origins of the high selectivity of nFeS, the removal of REEs by the capping layer and the FeS-core were separately investigated. Specifically, given the hard and soft acid base principle (HASB) and the square antiprism coordination geometry of Y(Ⅲ), the adsorption of Y(Ⅲ) by the capping layer was predominantly attributed to C O and –NH 2 serving as a monodentate ligand to strongly chelate with Y(Ⅲ), while Y(Ⅲ) interacted with Fe–O on the FeS-core and –COOH more via ion-exchange with Y(Ⅲ). Collectively, cooperative interactions between the capping layer and FeS-core resulted in the overall highly selective adsorption of Y(Ⅲ) by nFeS, suggest this approach has significant potential for future practical remediation and recovery applications to Y(Ⅲ) rich mining wastewaters. [ABSTRACT FROM AUTHOR]

Phytoremediation technology is an appropriate and eco-friendly technique with high efficiency to reduce heavy metal hazards from a contaminated environment. This study analyzed the effects of individual titanium dioxide nano-particles (TiO2 NPs) and combined with EDTA (TiO2 NPs+ EDTA) on phytoremediation of arsenic (As), copper (Cu), and cadmium (Cd) from copper mine wastewater using Lemna minor. The experiments were exposed using different concentrations of TiO2 NPs (200 and 300 mg kg−1) and EDTA (2 g kg−1) in seven treatments during 10 days. The content of As, Cu, and Cd was measured in plant tissues to calculate the total metal extraction (Ct), bioaccumulation factor (BF), and removal efficiency (RE). The content of As and Cu in the plant showed that uptake depended upon TiO2 NP concentration, and the Ct, BF, and RE values were affected by concentration of TiO2 NPs in wastewater. Adding 200 mg kg−1 TiO2 NPs to mine wastewater significantly increased the plant biomass (66.5%), relative growth rate (42.2%), relative growth factor (33.9%), and tolerance index (39.2%) compared to the individual wastewater treatment. Adding 200 mg kg−1 TiO2 NPs enhanced the As content, Ct, and BF values to 382.5± 41.2 mg kg−1, 122.1± 17.9 μg plant−1, and 664.2±161.2, respectively, while the combined use of TiO2 NPs+ EDTA and individual application of EDTA significantly decreased As uptake compared with wastewater treatment. For As, the RE (54.7%) and total absorbed (1786 kg ha−1 year−1) reached the maximum values following the application of 300 mg kg−1 TiO2 NPs, which were 25.8% and 30.1% higher than the control wastewater treatment, respectively. Furthermore, the BF values in control wastewater treatment showed that L. minor was known as a hyper-accumulate plant for the Cu metal, whereas the Ct, RE, and BF values increased due to applying individual TiO2 NPs and combined TiO2 NPs+EDTA. These results suggest that using TiO2 NPs for phytoremediation of contaminated water is helpful in enhancing As accumulation, whereas the L. minor is also a useful plant for Cu accumulation. [ABSTRACT FROM AUTHOR]

Mining wastewater can have adverse effects on the ecosystem; thus, treatment before discharging into the environment is of utmost importance. This manuscript reports on the effect of mining wastewater on the environment. Moreover, the currently used, effective and commercialised mine wastewater treatment technologies such as SAVMIN®, SPARRO®, Biogenic sulphide, and DESALX® are reported in this study. These technologies integrate two or more separation processes, which have been proven to be effective for the high recovery of salts and water for reuse. Some of the technologies reported can significantly recover salts and >95% of water. Modern pilot-stage and laboratory-scale treatment systems used for the recovery and removal of metals are also reported herein. Since some treatment technologies can generate highly toxic sludge and other waste products, the management of the generated waste was also considered. Some studies have focused on the treatment of wastewater at the laboratory level using the adsorption process. Most adsorbents exhibit promising results; however, there is insufficient research on reusability, toxic sludge management, and the economic analysis of the systems. Moreover, the implementation of adsorption systems in wastewater is necessary. Furthermore, the integration of treatment systems to recover precious metals at low concentrations is desirable in addition to water reclamation to achieve circular mine water., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Heavy metal pollution threatens aquatic systems worldwide, and mining activities are an important pollution source. Currently, the treatment of polluted water using a cost-effective technology that can purify multiple pollutants and is sustainable, environmentally friendly, and simple is a major challenge. The in situ preparation of Mg–Al layered double hydroxides (LDHs) and the concurrent treatment of Zn, Cd, and Pb from mining wastewater are important for preventing multiple steps and increasing adsorption sites. This study focused on mining wastewater containing high concentrations of Mg2+ and Al3+, with anion chemistry controlled by SO42−, which facilitates the formation of LDHs. The required amounts of Mg2+ and Al3+ ions were added to the wastewater, and the conditions for the creation of Mg–Al LDHs were controlled. The heavy metals in the experimental wastewater were effectively removed after the treatment via Mg–Al LDH formation. The X-ray diffraction of the post-treatment products suggested the formation of Mg–Al LDHs. The Mg/Al molar ratio (2.3:1) in the product approached the initial ratio (2:1), which meets the general limits of Mg–Al LDH formation. Scanning electron microscopy revealed that the products had a sheetlike stacked morphology, providing evidence for the formation of Mg–Al LDHs. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy indicated that SO42− might be the intercalated anion in the Mg–Al LDH layers. Consequently, SO42− was removed from the mining wastewater, as it was captured between the LDH layers during the formation reaction of Mg–Al LDHs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Unique challenges of mining wastewater, antisclants (AS) for MLD/ZLD. • Coupling of AS and antiscalant deactivation technology (ASDT) for higher recovery. • Advantages and disadvantage of ASDT for the mining wastewater application. Mining wastewater is inherently challenging to achieve zero or minimal liquid discharge (ZLD/ MLD) due to the high scale of the wastewater and the physical site constraints. This article highlights contextualized challenges for mining applications and also proposes a novel perspective on coupling antiscalants (AS) and downstream antiscalant deactivation technology (ASDT). ASDT is a relatively new concept that overcomes the limitation of water recoveries at the maximal TDS of 70 g/L by treating and desalting brines. The coupling of AS and ASDT can hence result in lower treatment costs by enhancing crystallization performance and enhancing water recovery with higher RO recoveries. Mining-specific scales, unique wastewater combinations, and physical constraints of mining sites are bottlenecks, and their potential mitigation methods are further explored in this article. Overall, this article provides an overview of the AS and ASDT applications and provides insightful future perspectives to address current challenges in mining wastewater applications. [ABSTRACT FROM AUTHOR]

Iron (Fe) and aluminium (Al) contamination due to mining activities has increased considerably and became a serious environmental problem. Phytoremediation is an emerging green technology that uses plants to treat heavy metal contaminated environment. In this study, Scirpus grossus was exposed to synthetic mining wastewater (binary mixture of Fe and Al with a mass ratio of 3:1) to assess its ability to phytoremediate Fe and Al with different treatment concentrations (90 mg/L Fe + 30 mg/L Al – 450 mg/L Fe + 150 mg/L Al). The plants were exposed for 102 d in a subsurface batch system. The results show that the S. grossus accumulated Fe and Al simultaneously in biomass throughout the study. The maximum accumulations of Fe and Al were found on Day 42 in the plant roots (50,277 mg/kg Fe in 450 mg/L Fe + 150 mg/L Al treatment and 7,744 mg/kg Al in 300 mg/L Fe + 100 mg/L Al treatment). The bioaccumulation factor and translocation factor of S. grossus were found to be greater than 1 and less than 1, respectively, for the two metals, indicating that this species is a hyperaccumulator that uses phytostabilization in the phytoremediation of Fe and Al. [ABSTRACT FROM AUTHOR]

• A Fe-Chitosan-coated sensor was developed for in situ As(III) detection. • The sensor was successfully applied for mining wastewater and soil leachate. • The sensor displayed good selectivity and reproducibility in real wastewater. • The interference from metal ions was found negligible for As(III) detection. A novel As(III) sensor was developed by co-electrodepositing a Fe-Chitosan composite to a screen-printed carbon electrode sensor. The newly developed Fe-Chitosan-coated carbon electrode sensor exhibited successful As(III) detection in mining wastewater and soil leachate using square wave anodic stripping voltammetry (SWASV). A noticeable peak was observed at +0.15 V associated with stripping current of As(III) for both real wastewater samples. The calibration curves showed strong correlations with respect to As(III) with the limit of detection (LOD) of 1.12 ppb for mining wastewater and 1.01 ppb for soil leachate, respectively. Lower relative standard deviations (RSD) were obtained with 2.91% for mining wastewater and 4.54% for soil leachate during repeated measurements (n = 8), respectively, indicating enhanced stability for As(III) detection in the real wastewater application. The interference from copper and other metal ions (e.g., Zn(II), Pb(II) and Cd(II)) was found negligible for As(III) detection using the polymer modified Fe-coated electrode sensor, which suggests that the Fe-chitosan composite imparted the selectivity in the presence of other metal ions to As(III) detection in complex water matrix. These results demonstrate the applicability of a novel Fe-Chitosan-coated carbon electrode sensor to real wastewater As(III) pollution monitoring with the acceptable range of characteristics. [ABSTRACT FROM AUTHOR]

Mine wastewater (MW) is often rich in heavy metals that can have measurable effects on humans. The storage and treatment of MW remains a challenge for most mining companies. Iron (Fe) in MW was removed by using extracts from Eucalyptus globulus (EG); Callistemon viminalis (CV); and Persea americana (AS). Fe was removed from MW samples with an initial concentration of 5.53 mg Fe mL−1; 4.63 mg Fe mL−1 and 4.40 mg Fe mL−1 using EG leaves, CV flowers and AS seed extracts, respectively. Conditions of the MW decontamination were studied by varying the dosage of the plant extracts, the temperature of the medium and the contact time between the MW and the plant extracts. Undiluted plant extracts—which were mixed with the MW and heated at 45 °C for 3 h—gave the highest Fe-removal efficiency for CV (70%) and AS (53%) extracts, respectively. Similarly, EG extracts, albeit heated at 25 °C, showed a higher Fe-removal efficiency (85%) than the CV and AS extracts at low to high temperatures. The residual Fe concentration in the MW was 0.83 mg Fe mL−1, 1.39 mg Fe mL−1 and 2.07 mg Fe mL−1 for EG, CV and AS extracts, respectively. Residue solid-phase deposits from the precipitation reaction of the MW with the plant extracts were collected and analyzed. Fe was among the byproducts detected in the deposited material. The characterization of the annealed solid-phase deposits revealed Fe precipitates as maghemite-C (Fe2O3) and magnetite (FeFe2O4) nanoparticles. Therefore, the MW quality and form were improved, making it reusable for other purposes.

Wastewater from the mining industry is a concern because most of the time it contains heavy metals with concentrations above permissible levels, posing a threat to terrestrial and aquatic life. The study was conducted to evaluate the effectiveness of locally available waste materials (waste rock, tailings, coal ash clinker, and slag) generated by BCL (Ltd) mine, a copper and nickel mining and smelting company in Botswana, for removal of nickel and copper from the real mining wastewater. Batch adsorption studies were conducted to establish the adsorptive efficiency and kinetics of each media with respect to nickel and copper ions. The best media was further evaluated through fixed bed column studies at 24 and 48 h empty bed contact time. The results indicate that the percentage removal for coal ash clinker, waste rock, smelter slag and tailings was 98%, 15%, 3% and −3% with respect to copper ions, and 46%, 9%, 7% and 2% with respect to nickel ions for each media respectively. Coal ash clinker followed pseudo first order kinetic model and Langmuir isotherm model with respect to nickel ions indicating the dominance of physisorption and mono layer coverage respectively. The Langmuir separation factor (R L ) was 0.37 suggesting favourable adsorption onto the media. Fixed bed column studies revealed that copper was completely retained in the bed at both 24 and 48 h contact times. In the case of nickel, removal efficiency ranged between 83% and 99% when contact time was 48 h and between 68% and 99% when the contact time was reduced to 24 h. Breakthrough was not reached after 19 bed volumes. It can be concluded that coal ash clinker is a better candidate for the removal of copper and nickel ions from mining wastewater. [ABSTRACT FROM AUTHOR]

Naturally occurring manganese (Mn) oxide minerals often form by microbial Mn(II) oxidation, resulting in nanocrystalline Mn(III/IV) oxide phases with high reactivity that can influence the uptake and release of many metals (e.g., Ni, Cu, Co, and Zn). During formation, the structure and composition of biogenic Mn oxides can be altered in the presence of other metals, which in turn affects the minerals' ability to bind these metals. These processes are further influenced by the chemistry of the aqueous environment and the type and physiology of microorganisms involved. Conditions extending to environments that typify mining and industrial wastewaters (e.g., increased salt content, low nutrient, and high metal concentrations) have not been well investigated thus limiting the understanding of metal interactions with biogenic Mn oxides. By integrating geochemistry, microscopic, and spectroscopic techniques, we examined the capacity of Mn oxides produced by the Mn(II)-oxidizing Ascomycete fungus Periconia sp. SMF1 isolated from the Minnesota Soudan Mine to remove the metal co-contaminant Co(II) from synthetic waters that are representative of mining wastewaters currently undergoing remediation efforts. We compared two different applied remediation strategies under the same conditions: coprecipitation of Co with mycogenic Mn oxides versus adsorption of Co with pre-formed fungal Mn oxides. Co(II) was effectively removed from solution by fungal Mn oxides through two different mechanisms: incorporation into, and adsorption onto, Mn oxides. These mechanisms were similar for both remediation strategies, indicating the general effectiveness of Co(II) removal by these oxides. The mycogenic Mn oxides were primarily a nanoparticulate, poorly-crystalline birnessite-like phases with slight differences depending on the chemical conditions during formation. The relatively fast and complete removal of aqueous Co(II) during biomineralization as well as the subsequent structural incorporation of Co into the Mn oxide structure illustrated a sustainable cycle capable of continuously remediating Co(II) from metal-polluted environments. [Display omitted] • Co(II) is quickly removed from simulated mining wastewater by mycogenic Mn oxides. • Co(II) is adsorbed onto and incorporated into fungal Mn oxides. • Fungal Mn oxides co-precipitated with Co(II) or pre-formed showed no difference in Co(II) removal ability. • Mycogenic Mn oxides may provide an effective Co bioremediation strategy. [ABSTRACT FROM AUTHOR]

Electrode material is the key factor for improving the electrochemical performance of capacitive deionization. In this study, a multichannel electrode material derived from soybean straw was prepared by pyrolytic carbonization and dual-activation, characterized, and used as an electrode material in capacitive deionization (CDI) cells to remove sulfate. The results showed that the sulfate adsorption capacity of dual-activated CA-NPSSC-1 of 17.16 mg/g was higher than that of pristine SSC (3.28 mg/g) due to its larger specific surface area, suitable pore structure, superior conductivity, and larger specific capacitance. The electrosorption mechanism of CA-NPSSC-1 electrode included EDL ion storage and pseudocapacitance storage. The EDL contribution and pseudocapacitance contribution were 72.06 % and 27.94 %, respectively, at a scan rate of 5 mV/s. Actual wastewater experiments have shown that the sulfate concentration in mining wastewater was reduced to 158.85 mg/L after recycling treatment, which meets the relevant standards. This work provides new ideas and methods for the treatment of high-salinity mining wastewater. [Display omitted] • The CA-NPSSC-1 electrode was demonstrated to have high capacitive deionization performance and regeneration performance. • Electrostatic adsorption and non-electrostatic adsorption (physical adsorption and chemical adsorption) were involved. • The contributions of EDL storage and pseudocapacitive storage to electroabsorption were 72.06% and 27.94%, respectively. • The prepared CA-NPSSC-1 electrode could effectively treat actual mining wastewater. [ABSTRACT FROM AUTHOR]

A novel bismuth (Bi)-biopolymer (chitosan) nanocomposite screen-printed carbon electrode was developed using a Bi and chitosan co-electrodepositing technique for detecting multiple heavy metal ions. The developed sensor was fabricated with environmentally benign materials and processes. In real wastewater, heavy metal detection was evaluated by the developed sensor using square wave anodic stripping voltammetry (SWASV). The nanocomposite sensor showed the detection limit of 0.1 ppb Zn2+, 0.1 ppb Cd2+ and 0.2 ppb Pb2+ in stock solutions. The improved sensitivity of the Bi-chitosan nanocomposite sensor over previously reported Bi nanocomposite sensors was attributed to the role of chitosan. When used for real wastewater samples collected from a mining site and soil leachate, similar detection limit values with 0.4 ppb Cd2+ and 0.3 ppb Pb2+ were obtained with relative standard deviations (RSD) ranging from 1.3% to 5.6% (n = 8). Temperature changes (4 and 23 °C) showed no significant impact on sensor performance. Although Zn2+ in stock solutions was well measured by the sensor, the interference observed while detecting Zn2+ in the presence of Cu2+ was possibly due to the presence of Cu-Zn intermetallic species in mining wastewater. Overall, the developed sensor has the capability of monitoring multiple heavy metals in contaminated water samples without the need for complicated sample preparation or transportation of samples to a laboratory.

This study was conducted to assess the removal of arsenic (As) and heavy metals from mining wastewater by the combination of adsorption, using modified iron-ore drainage sludge, and horizontal-subsurface-flow constructed wetland with common reed (Phragmites australis). The pilot-scale experiment with a constant flow rate of 5 m3/day was operated for four months using real wastewater from a Pb–Zn mine in northern Vietnam. Atomic absorption spectroscopy was used for elemental analysis in wastewater and plant. X-ray diffraction (XRD), surface charge measurements (by a particle charge detector (PCD)), Fourier-transform infrared (FTIR), and surface area Brunauer–Emmet–Teller (BET) measurements were performed to determine the characteristics of the adsorbent. The results showed that the average removals of As, Mn, Cd, Zn, and Pb by the combined system with limestone substrate during four months were 80.3%, 96.9%, 79.6%, 52.9%, and 38.7%, respectively. The use of another constructed wetland substrate, laterite, demonstrated better removal efficiency of As than limestone. The concentrations of As and heavy metals in the effluent were lower than the limits established by the QCVN 40:2011/BTNMT for industrial wastewater, which indicated the feasibility of combining adsorption and constructed wetland for the treatment of mining wastewater.

The removal of copper, nickel, and cobalt ions from synthetic mining wastewater was investigated in this study using micellar-enhanced ultrafiltration (MEUF). The effect of surfactant-to-metal (S/M) ratio and pH on metal rejection and permeate flux were examined. A Monte Carlo-based artificial neural network (ANN) modeling approach was proposed to predict the MEUF performance and to reveal the importance of process parameters. The results showed that model-predicted values were in agreement with experimental data ( R > 0.99). S/M ratio and pH had relatively greater contributions (30-50%) to the metal rejection rate and permeate flux, whereas sampling time contributed less (10%), which indicated high MEUF efficiency. An S/M ratio of 8.5 with a pH of 8-10 was found to be the optimal condition for MEUF, under which the rejection rates of all three metals exceeded 99% and were in compliance with Canadian environmental standards. Flux decrease and concentration polarization effect were observed during the experimental procedure. Statistical analysis showed that the type of metal examined in this study did not affect MEUF performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • A hybrid ZIF-8@FeNPs was successfully prepared. • The removal mechanism of Sb (V) was proposed. • Sb(V) in mining wastewater (1.121 mg·L−1) was removed 89.7 %. • ZIF-8@FeNPs was separated and recycled. The removal of antimonate (Sb(V)) species from wastewaters has become a growing concern due to their known genotoxicity and carcinogenicity. In this paper, a hybrid ZIF-8@FeNPs material was synthesized from Zeolite Imidazole Framework-8 (ZIF-8) and zero-valent iron nanoparticles (n ZVI) and subsequently used to remove Sb(V) from aqueous solution. Characterization indicated that ZIF-8@FeNPs were successfully synthesized and that the valence state of Sb(V) did not change during the removal process, where adsorption of Sb(V) was facilitated by the high specific surface area and porosity of the hybrid. Advanced characterization also showed that Zn-OH and iron oxides were adsorbed on the material after complexation with Sb(V). Kinetic, isothermal, and thermodynamic modeling indicated that the adsorption process followed pseudo-second-order kinetics, via multilayer adsorption which was spontaneous and endothermic. A Sb(V) removal mechanism based on adsorption was proposed. In mining wastewater containing 1.121 mg·L−1 Sb(V), 89.7 % could be removed by the material. During repeated reuse of ZIF-8@FeNPs for the removal of 1 mg·L−1 Sb(V) through four successive cycles, the removal efficiency was still relatively high (39.1 %) after the fourth cycle indicating good potential for practical applications. In addition, ZIF-8@FeNPs also exhibited magnetic properties, which demonstrated that Sb(V) could be easily recovered from wastewater post removal by ZIF-8@FeNPs. [ABSTRACT FROM AUTHOR]

[Display omitted] • COFs and CNTs composites were synthesized by in-situ synthesis. • The synergistic effect improved the adsorption capacity and selectivity. • The removal mechanism of samples was clarified through various characteristic modes. • The problem of U (VI) removal from the rare earth tailings wastewater had been solved. The wastewater containing uranium produced in the mining process is harmful to the environment and life safety due to the inherent biotoxicity and radioactivity of uranium. In this paper, 4,4′-diamino-[1,1′-biphenyl]-3,3′-diol and 2,4,6-triformylphloroglucinol were in situ synthesized β -ketoenamine covalent organic frameworks (COFs) on the surface of carbon nanotubes (CNTs) to obtain a composite of CNT/COF-OH for removal uranium in the rare earth tailings wastewater. Grafting COFs with a large number of specific uranium-binding groups and redox-active sites on the surface of CNTs, CNT/COF-OH can effectively enhance the uranium ion selectivity and adsorption capacity. Furthermore, CNTs have good electron transport capacity and π-conjugation properties, electrons can be effectively transferred from CNTs to COFs, which increases the electron density of the adsorption functional groups, resulting in an increase of the adsorption energy and reductive activity for U (VI), thus improving the removal efficiency. In addition, the skeleton of COFs can be supported by CNTs, thus reducing collapse. Through the synergistic effect of composite, CNT/COF-OH had a good uranium adsorption capacity of 518.2 mg g−1. The adsorption capacity of CNT/COF-OH was increased by 390.7 %, 54.6 %, and 84.5 % compared with those of single CNTs, COF-OH, and mixed CNT + COF-OH, respectively. The selective separation coefficient of CNT/COF-OH was 1.6 times higher than that of COF-OH. The experiment of uranium removal was carried out in the rare earth tailings wastewater using CNT/COF-OH, the removal rate reached 96.7 %. The COFs modified CNTs with synergistic effect have important theoretical and practical significance for the safety problems caused by harmful ions in wastewater. [ABSTRACT FROM AUTHOR]

Heavy-metal-bearing wastewater is among the most formidable challenges the mining industry currently faces in maintaining its social license to operate. Amongst the technologies available for metal ion adsorption, bioinspired engineering nanomaterials have emerged as one which exhibits great promise. However, current processes used for the preparation of adsorbents (including nanoscale activated carbon and biochar) represent a source of adverse impacts on the environment. In contrast, the application of biogenic-nanoparticles, i.e., those derived from processes catalysed by microbiota, has received significant attention in the last few years. Coupled with this, the use of naturally occurring reagents is of major importance for the sustainability of this emerging industry. This paper analyses the life cycle assessment (LCA) of the synthesis of adsorbents derived from agricultural wastes. Moreover, rather than simply recovering the ecotoxic metals from wastewater, the potential to valorise dissolved metals into high-value metallic nanoparticle products is discussed. LCA analysis revealed that the adsorbent had some adverse impact on the environment. The agricultural wastes contributed 27.86% to global warming, 54.64% to ozone formation, 33.06% to fine particles, and 98.24% to marine eutrophication. Mining wastewater is an important, and largely currently unexploited, source of metal value. However, the often-low concentration of such metals dictates that their conversion into high-value products (such as engineered nanoparticles) is an important new research frontier. Within this the use of biosynthesis methods has emerged as having great potential due to a range of beneficial attributes, including low cost, high efficacy and/or environmental compatibility. [Display omitted] • LCA of adsorbents from agricultural wastes revealed an impact on the environment. • Mining wastewater has high potential as a source of multi-metal nanoparticles. • The challenges of nano-synesis in mining wastewater lie in the presence of cations. [ABSTRACT FROM AUTHOR]

Low nitrogen (N) removal efficiency limits the potential of microalgae technology for the treatment of high nitrogen and low carbon rare earth tailings (REEs) wastewater. In this study, waste corncob was utilized as a biocarrier immobilizing Chlamydopodium sp. microalgae to realize high-efficient treatment of the REEs wastewater. In only 2.5 d, corncob-immobilized microalgae allowed the residual concentrations of N lower than the emission standards, and ammonia nitrogen (NH 4 +-N) removal rate is 83.3 mg L−1·d−1, total inorganic nitrogen (TIN) removal rate is 86.7 mg L−1·d−1, which was 18.5 times that of the previously-reported microalgae (4.68 mg L−1·d−1). Compared with other microalgae immobilization carriers, corncob possesses the ability to release available carbon sources for microalgae. Composition analysis and sugar verification experiments showed that the main content of TOC released by corncob was monosaccharide, and in a certain range, the removal rate of N was positively correlated with the TOC concentration. The utilization of biomass wastes with dual functions as biological carriers has great potential to improve the performance of microalgae, and is conducive to the development of engineering applications. [Display omitted] • Rapid removal of NH 4 +-N and TIN by microalgae was achieved in REEs wastewater. • The removal efficiency of TIN can reach 100%, and rate can reach 86.7 mg L−1·d−1. • The removal rate of N by corncob-immobilized microalgae reached the highest. • Corncob possess dual functions of biocarrier and available carbon source. [ABSTRACT FROM AUTHOR]

Arsenic contamination is an increasing global environmental problem, especially in mining industry wastewater where both arsenite (As(III)) and arsenate (As(V)) have been routinely detected. In this paper, a novel porous metal-organic framework material (ZIF-8) was composited with iron nanoparticles (FeNPs) to form a functional material (ZIF-8@FeNPs) for the simultaneous removal of As(III)/(V) from wastewater. The material effectively removed both As(III) and As(V) with removal efficiencies of 99.9 and 71.2%, respectively. Advanced characterization techniques including X-ray photoelectron spectroscopy (XPS) and Fourier infrared (FTIR) indicated that removal of As(III) and As(V) involved complex formation. Adsorption kinetics followed a pseudo-second order kinetics indicating adsorption involved chemisorption. After four cycles of reuse the he removal rate of As species was still relatively high at > 60% When ZIF-8@FeNPs were used to remove As from real wastewater from acid mines the removal efficiency was 94.27%. Finally, a As(III) and As(V) removal mechanism was proposed. [Display omitted] • ZIF-8@FeNPs can effectively remove As(III) and As(V). • Removal of As(III) and As(V) by forms complex. • The adsorption process is one of chemisorption. • A 94.27% of As (V) in mining wastewater was removed. [ABSTRACT FROM AUTHOR]

Mining wastewater was treated using quaternized pine sawdust (QPSD) anion exchanger. The wastewater contained heavy metals (e.g. Sb, As, Co, Cr, Ni, V, U), NO3−, among others, and a high concentration of SO42−. A series of column cycles imitating a real treatment process was conducted (three sorption/desorption cycles, a maintenance cycle with HCl and two sorption/desorption cycles). The effects of contact time and temperature (5°C and 23°C) were studied to assess the applicability of QPSD in the treatment of cold mining effluents. At 5°C, 85% of nickel was removed but the sorption was slower than at 23°C (initial Ni concentration was about 39 µg/l). Nickel was also removed in column efficiently (85–100% reduction). Treatment with HCl during the maintenance cycles did not hinder nickel sorption. Nickel was desorbed with both NaCl and HCl. Contrary to expectations, nitrate was not sorbed. QPSD showed selectivity towards nickel. However, uptake of uranium and cobalt was detected in column. Neutron activation analysis was used to detect metals sorbed onto the QPSD, and uptake of several metals was confirmed. [ABSTRACT FROM AUTHOR]

The main purpose of this study was to examine commercial clay-based adsorbents without modifications for ammonium adsorption and compare their ability to reduce the amount of ammonium from a liquid phase. For the first time, to our knowledge, bentonite, chabazite, clinoptilolite, and phillipsite were tested for ammonium adsorption in the same study. The comparison of the materials was conducted in both simulated and real wastewaters to obtain reliable information about their performance in real conditions. It was found that all the adsorbents possessed ammonium removal capacity, but the amount reduced depended on the pH and other cations present in the examined liquid. Experimental isotherms were compared with the Langmuir, Freundlich, and Sips isotherms. Among these three isotherm models, the best fit was found with the Sips model in all of the cases. It was also observed that zeolite from Sigma–Aldrich had the best maximum ammonium adsorption capacity of the examined adsorbents. All in all, in different conditions, the zeolite and the two chabazites were the best ones to adsorb ammonium. [ABSTRACT FROM PUBLISHER]

Membrane distillation (MD) could be applicable in zero liquid discharge applications. This is due to the fact that MD is applicable at high salinity ranges which are generally outside the scope of reverse osmosis (RO) applications, although this requires proper management of precipitating salts to avoid membrane fouling. One way of managing these salts is with MD crystallisation (MDC). This paper focuses on the applicability of MDC for the treatment of mining wastewater by thermodynamically modelling the aqueous chemistry of the process at different temperatures. The paper is based on the typical brine generated from an RO process in the South African coal mining industry and investigates the effect water recovery and operating temperature have on the salts that are predicted to crystallise out, the sequence in which they will crystallise out and purities as a function of the water recovery. The study confirmed the efficacy of using thermodynamic modelling as a tool for investigating and predicting the crystallisation aspects of the MDC process. The key finding from this work was that, for an MDC process, a purer product can be obtained at higher operating temperatures and recoveries because of the inverse solubility of calcium sulphate. [ABSTRACT FROM AUTHOR]

Limestones and their modifications from Nordkalk Corporation (Finland) flotation fines (FF) and filter sand (FS) as potential adsorbents for AMD treatment and wastewater purification from Cu, Fe, Zn and Ni ions were studied. Limestones were capable of binding significant amounts of Cu and Fe from synthetic AMD solutions and wastewater, while unmodified limestones were not good for Zn and Ni removal. Two methods of surface area modification were suggested. The first one with 2 M solution of NaCl and the second one with wastewater from Norilsk Nickel Harjavalta. The structure of materials and their surface area were characterized by SEM, EDX, MIR spectroscopy and nitrogen adsorption methods. Optimal amount of adsorbents for different model and real solutions was found. Adsorption kinetics showed that the adsorption equilibrium was reached within approximately 8 h. The kinetic data fits to a pseudo second order model with correlation coefficients greater than 0.999. The adsorption capacity was the highest at solution pH range of 6–7. Langmuir, Toth and Sips models were used to fit the adsorption isotherms. Based on the parameters calculated from models, the adsorption capacity decreased in the order of Cu > Fe > Zn > Ni for FF and Fe > Cu > Zn > Ni for FS. The research showed that the proposed modified limestones can be successfully used for AMD neutralization and removal of Cu(II), Fe(III), Zn(II) and Ni(II). [ABSTRACT FROM AUTHOR]