Natural solution for the remediation of multi-metal contamination: application of natural amino acids, Pseudomonas fluorescens and Micrococcus yunnanensis to increase the phytoremediation efficiency.

Natural amino acids (NAA) have been rarely investigated as chelators, despite their ability to chelate heavy metals (HMs). In the present research, the effects of extracted natural amino acids, as a natural and environmentally friendly chelate agent and the inoculation of Pseudomonas fluorescens (PF) and Micrococcus yunnanensis (MY) bacteria were investigated on some responses of quinoa in a soil polluted with Pb, Ni, Cd, and Zn. Inoculation of PGPR bacteria enhanced plant growth and phytoremediation efficiency. Pb and Cd were higher in quinoa roots, while Ni and Zn were higher in the shoots. The highest efficiencies were observed with NAA treatment and simultaneous inoculation of PF and MY bacteria for Ni, Cd, Pb, and Zn. The highest values of phytoremediation efficiency and uptake efficiency of Ni, Cd, Pb, and Zn were 21.28, 19.11, 14.96 and 18.99 µg g-1, and 31.52, 60.78, 51.89, and 25.33 µg g-1, respectively. Results of present study well demonstrated NAA extracted from blood powder acted as strong chelate agent due to their diversity in size, solubilizing ability, abundant functional groups, and potential in the formation of stable complexes with Ni, Cd, Pb, and Zn, increasing metal availability in soil and improving phytoremediation efficiency in quinoa.

This study focused on an underexplored topic, the potential of natural amino acids (NAA) and plant growth-promoting rhizobacteria (PGPRs) to enhance phytoremediation efficiency of quinoa in a multi-metal contaminated soil with the waste recycling approach. Despite their chelating abilities, NAA have been rarely studied in this context. In the present study, the effects of extracted NAA, acting as environmentally friendly chelating agents, and the inoculation of Pseudomonas fluorescens (PF) and Micrococcus yunnanensis (MY) bacteria were examined on the responses of quinoa in a soil contaminated with Pb, Ni, Cd, and Zn.

Tentative identification of phytochelatins, their derivatives, and Cd-phytochelatin complexes in Ocimum basilicum L. roots by Paper Spray Mass Spectrometry.

An unprecedented and direct PS-MS (paper spray ionization mass spectrometry) method was proposed for the detection of native peptides, that is, glutathiones (GSHs), homoglutathiones (hGSHs), and phytochelatins (PCs), in basil (Ocimum basilicum L.) roots before and after cadmium exposure. The roots were submitted to cold maceration followed by sonication with formic acid as the extractor solvent for sample preparation. PS-MS was used to analyze such extracts in the positive mode, and the results allowed for the detection of several GSHs, hGSHs, and PCs. Some of these PCs were not distinguished in the control samples, that is, basil roots not exposed to cadmium. Other PCs were noticed in both types of roots, uncontaminated and cadmium-contaminated, but the intensities were higher in the former samples. Moreover, long-time exposure to cadmium stimulated the formation of some of these PCs and their cadmium complexes. The results, therefore, provided some crucial insights into the defense mechanism of plants against an external stress condition due to exposure to a toxic heavy metal. The present study represents a promising alternative to investigate other crucial physiological processes in plants submitted to assorted stress conditions.

Assessment of heavy metal contamination in leafy vegetables: implications for public health and regulatory measures.

Heavy metal contamination in leafy vegetables poses significant health risks, highlighting the urgent need for stringent monitoring and intervention measures to ensure food safety and mitigate potential adverse effects on public health. This study investigates the levels of heavy metals, including cadmium (Cd), chromium (Cr), nickel (Ni), lead (Pb), zinc (Zn), and copper (Cu), in locally grown and commercially available leafy vegetables, comparing them to the safety limits established by WHO/FAO. The results revealed that levels of Cd, Cr, Ni, and Pb in the vegetables exceeded WHO/FAO limits, while Zn and Cu remained within permissible bounds. Marketed vegetables exhibited higher metal concentrations than those from nearby farms. For Cu (0.114-0.289 mg/kg) and Zn (0.005-0.574 mg/kg), the daily intake of metals (DIM) was below the dietary intake (DI) and upper limit (UL). Cd's DIM (0.031-0.062 mg/kg) remained below the UL but exceeded the DI. Marketed kale and mint surpassed both DI and UL limits for Ni, while local produce only exceeded the DI. All vegetables had DIM below the DI, except for mint and kale. For Pb, every vegetable exceeded DI limits, with market samples contributing significantly. Cr's DIM ranged from 0.028 to 1.335 mg/kg, for which no set maximum daily intake exists. The health risk index (HRI) values for Zn, Cd, Cu, Ni, and Pb suggested potential health risks associated with leafy greens, while Cr's HRI was below 1. The study underscores the need for stringent monitoring and intervention measures to mitigate the health risks posed by heavy metal contamination in leafy vegetables. These findings suggest that consuming these leafy greens may put consumers at considerable risk for health problems related to Cd, Cu, Ni, Pb, and Zn exposure.

Assessment of heavy metal levels in polyculture fish farms and their aquatic ecosystems: an integrative study addressing environmental and human health risks associated with dam water usage.

This study examines the levels of heavy metals in polyculture fish (Labeo rohita, Cyprinus carpio, and Catla catla), water, and sediment in Tanda Dam, Kohat, Pakistan, aiming to understand environmental and health risks. Samples of fish, water, and sediment were collected from 3 fish farms, and heavy metal concentrations were measured using a Flame Atomic Absorption Spectrophotometer (AAS). Results reveal that C. catla exhibited significantly higher (p < 0.05) levels of Zn than other fish species. Conversely, C. carpio showed significantly higher (p < 0.05) concentrations of Pb, Cd, Cr, Mn, Cu, As, and Ni than other species. The heavy metal hierarchy in C. carpio was found to be Zn > Cu > Pb > Cr > Cd > Mn > As > Ni. While heavy metal levels in L. rohita and C. catla generally fell within reference ranges, exceptions were noted for Zn, Pb, and Cd. Conversely, in C. carpio, all metals exceeded reference ranges except for Cu and Ni. Principal Component Analysis (PCA) indicated a close relationship between water and sediment. Additionally, cluster analysis suggested that C. catla formed a distinct cluster from L. rohita and C. carpio, implying different responses to the environment. Despite concerns raised by the Geoaccumulation Index (Igeo) and Contamination Factor (CF), particularly for Cd, which exhibited a high CF. Furthermore, Hazard Index (HI) values for all three fish species were below 1, suggesting low health risks. However, elevated Igeo and CF values for Cd suggest significant pollution originating from anthropogenic sources. This study underscores the importance of monitoring heavy metals in water for both environmental preservation and human health protection. Future research efforts should prioritize pollution control measures to ensure ecosystem and public health safety.

Analysis of Heavy Metal Characteristics and Health Risk Assessment of Dried Fish Marketed in Guangzhou, China.

This study investigated heavy metal contamination in dried fish sold in Guangzhou, China, and evaluated the resultant non-carcinogenic and carcinogenic health risks. Dried fish samples were purchased from Baiyun, Tianhe, Panyu, and Yuexiu districts in Guangzhou, where the population is substantial. They were randomly acquired in bustling supermarkets and farmers' markets, targeting the most popular dried fish in these areas. Sixty samples from five dried fish types (Stolephorus chinensis, Thamnaconus modestus, Nemipterus-virgatus, river fish, Ctenopharyngodon idella) were analyzed for chromium (Cr), arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) content. Quantification of the heavy metals were carried out by inductively coupled plasma mass spectrometry (ICP-MS) for Cr, As, Cd, and Pb, and an automatic mercury analyzer for Hg. The median concentration of these heavy metals in dried fish were 0.358 mg/kg, 2.653 mg/kg, 0.032 mg/kg, 0.083 mg/kg, and 0.042 mg/kg, respectively. Pollution severity was ranked as dried Nemipterus-virgatus > dried Stolephorus chinensis > dried Thamnaconus modestus > dried river fish > dried Ctenopharyngodon idella, with As being the most predominant pollutant. All fish types showed severe As pollution. Non-carcinogenic risks were identified in the consumption of dried Nemipterus-virgatus and dried Stolephorus chinensis for both genders, while potential carcinogenic risks were associated with four of the fish types. Women faced higher health risks than men from dried fish consumption. Consequently, we advise consumers to minimize their intake of dried fish and regulatory agencies conduct regular monitoring of heavy metal levels in commercially available dried fish to avert potential health risks.

Application of ion-exchange dynamic conditions in the recovery of precious metals from refining waste.

The objective of this study was to assess the potential for recovering precious metals from technological solutions using an ion-exchange dynamic method. Precious metals like platinum, palladium, rhodium, and gold are essential materials in various industries such as: automotive, electronics, pharmaceuticals, and jewellery. Due to their limited occurrence in primary sources, there is a growing trend in the market to extract these metals from secondary sources. The research involved conducting sorption and elution tests under different parameters to investigate their impact on the process in dynamic conditions. Additionally, an attempt was made to calculate the operational and total capacity of the resins, which has not been done previously for industrial solutions. The results showed that using Puromet MTS9200, Puromet MTS9850, and Lewatit MonoPlus MP600 resins, the sorption process could be effectively carried out in dynamic conditions with a contact time of 5 min between the technological solution and the resin bed. For optimal elution, the contact time between the eluent solution and the bed should range between 10 and 30 min. To improve rhodium sorption efficiency, it was found that neutralizing the technological solution to a pH of approximately 7 and using Lewatit MonoPlus MP600 resin could be beneficial.

Gestational exposure to organochlorine compounds and metals and infant birth weight: effect modification by maternal hardships.

BACKGROUND: Gestational exposure to toxic environmental chemicals and maternal social hardships are individually associated with impaired fetal growth, but it is unclear whether the effects of environmental chemical exposure on infant birth weight are modified by maternal hardships. METHODS: We used data from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study, a pan-Canadian cohort of 1982 pregnant females enrolled between 2008 and 2011. We quantified eleven environmental chemical concentrations from two chemical classes - six organochlorine compounds (OCs) and five metals - that were detected in ≥ 70% of blood samples collected during the first trimester. We examined fetal growth using birth weight adjusted for gestational age and assessed nine maternal hardships by questionnaire. Each maternal hardship variable was dichotomized to indicate whether the females experienced the hardship. In our analysis, we used elastic net to select the environmental chemicals, maternal hardships, and 2-way interactions between maternal hardships and environmental chemicals that were most predictive of birth weight. Next, we obtained effect estimates using multiple linear regression, and plotted the relationships by hardship status for visual interpretation. RESULTS: Elastic net selected trans-nonachlor, lead, low educational status, racially minoritized background, and low supplemental folic acid intake. All were inversely associated with birth weight. Elastic net also selected interaction terms. Among those with increasing environmental chemical exposures and reported hardships, we observed stronger negative associations and a few positive associations. For example, every two-fold increase in lead concentrations was more strongly associated with reduced infant birth weight among participants with low educational status (ß = -100 g (g); 95% confidence interval (CI): -215, 16), than those with higher educational status (ß = -34 g; 95% CI: -63, -3). In contrast, every two-fold increase in mercury concentrations was associated with slightly higher birth weight among participants with low educational status (ß = 23 g; 95% CI: -25, 71) compared to those with higher educational status (ß = -9 g; 95% CI: -24, 6). CONCLUSIONS: Our findings suggest that maternal hardships can modify the associations of gestational exposure to some OCs and metals with infant birth weight.

Exploring spatial and temporal symptoms of the freshwater salinization syndrome in a rural to urban watershed.

The freshwater salinization syndrome (FSS), a concomitant watershed-scale increase in salinity, alkalinity, and major-cation, and trace-metal concentrations, over recent decades, has been described for major rivers draining extensive urban areas, yet few studies have evaluated temporal and spatial FSS variations, or causal factors, at the subwatershed scale in mixed-use landscapes. This study examines the potential influence of land-use practices and wastewater treatment plant (WWTP) effluent on the export of major ions and trace metals from the mixed-use East Branch Brandywine Creek watershed in southeastern Pennsylvania, during the 2019 water year. Separate analysis of baseflow and stormflow subsets revealed similar correlations among land-use characteristics and streamwater chemistry. Positive associations between percent impervious surface cover, which ranged from 1.26 % to 21.9 % for the 13 sites sampled, and concentrations of Ca2+, Mg2+, Na+, and Cl- are consistent with road-salt driven reverse cation exchange and weathering of the built environment. The relative volume of upstream WWTP was correlated with Cu and Zn, which may be derived in part from corroded water-conveyance infrastructure; chloride to sulfate ratios (CSMR) ranged from ~6.3 to ~7.7× the 0.5 threshold indicating serious corrosivity potential. Observed exceedances of U.S. Environmental Protection Agency Na+ and Cl- drinking water and aquatic life criteria occurred in winter months. Finally, correlation between percent cultivated cropland and As and Pb concentrations may be explained by the persistence of agricultural pesticides that had been used historically. Study results contribute to the understanding of FSS solute origin, fate, and transport in mixed-use watersheds, particularly those in road salt affected regions. Study results also emphasize the complexity of trace-metal source attribution and explore the potential for FSS solutes to affect human health, aquatic life, and infrastructure.

Metalloproteins and metalloproteomics in health and disease.

Metalloproteins represents more than one third of human proteome, with huge variation in physiological functions and pathological implications, depending on the metal/metals involved and tissue context. Their functions range from catalysis, bioenergetics, redox, to DNA repair, cell proliferation, signaling, transport of vital elements, and immunity. The human metalloproteomic studies revealed that many families of metalloproteins along with individual metalloproteins are dysregulated under several clinical conditions. Also, several sorts of interaction between redox- active or redox- inert metalloproteins are observed in health and disease. Metalloproteins profiling shows distinct alterations in neurodegenerative diseases, cancer, inflammation, infection, diabetes mellitus, among other diseases. This makes metalloproteins -either individually or as families- a promising target for several therapeutic approaches. Inhibitors and activators of metalloenzymes, metal chelators, along with artificial metalloproteins could be versatile in diagnosis and treatment of several diseases, in addition to other biomedical and industrial applications.

Alkali-activated geopolymers based on calcined phosphate sludges and metakaolin.

The extraction of phosphorite ore in Tunisia has resulted in the discharge of substantial amounts of phosphatic sludge into the region's water system. To mitigate this environmental issue and prevent heavy metal leaching, a geopolymerization process was employed using two types of Tunisian calcined phosphate sludges (Cal-PS1 and Cal-PS2) as substitutes for alkali-activated metakaolin. This study aimed to investigate and compare the physical and mechanical properties of the resulting geopolymers. The optimal substitution ratio of metakaolin with calcined phosphate sludge was determined to be 1.5, equivalent to 20 wt.% of calcined phosphate sludge. Compressive strength tests conducted after 28 days of curing revealed values of 37 MPa for Cal-PS1 specimens and 28 MPa for Cal-PS2 geopolymers while compressive strength of geopolymers soaked in water for 28 days showed a decrease with the addition of phosphate sludges. The specific surface areas of Cal-PS1 geopolymers ranged from 16.3 to 16.9 m2/g and from 17.62 to 18.73 m2/g for Cal-PS2 specimens exhibiting a mesoporous structure. The elasticity modulus of the geopolymers was found to increase with the increase of the apparent density of geopolymers and with the sludges content but it tended to be lower than the Portland cement elasticity modulus. Leaching test was conducted to evaluate the potential environmental applications of the geopolymers. This test demonstrated effective containment of heavy metals within the geopolymers' network, except for low levels of arsenic.

Spatial distribution and health risks assessment of heavy metals in e-waste dumping sites from Pakistan.

The present study focused on to determine the concentration and health risk of heavy metals (Cu, Pb, Zn, Cd, Hg, Cr) in e-waste contaminated soils collected from different provinces of Pakistan. Further, the impact of heavy metals on soil enzyme activities and microbial community was also investigated. The concentration (mg/kg) of Hg, Zn, Fe, Cu, Pb, Cd, and Cr ranged between 0-0.258, 2.284-6.587, 3.005-40.72, 8.67-36.88, 12.05-35.03, 1.03-2.43, and 33.13-60.05, respectively. The results revealed that Lahore site of Punjab province indicated more concentration of heavy metals as compared to other sites. The level of Cr at all sites whereas Hg at only two sites exceeds the World Health Organization standards (WHO) for soil. Soil enzyme activity exhibited dynamic trend among the sites. Maximum enzyme activity was observed for urease followed by phosphatase and catalase. Contamination factor (Cf), Pollution load index (PLI), and geo-accumulation index (Igeo) results showed that all the sites are highly contaminated with Cu, Cd, and Pb. Hazard index (HI) was less than 1 for children and adults suggesting non-carcinogenic health risk. Principle component analysis results depicted relation among Cr, Fr, catalase, and actinomycetes; Cd, OM, urease, and bacteria, and Pb, Cu, Zn, Hg, and phosphatase, suggesting soil enzymes and microbial community profiles were influenced by e-waste pollution. Therefore, there is a dire need to introduce sustainable e-waste recycling techniques as well as to make stringent e-waste management policies to reduce further environmental contamination.

Assessment of the migration characteristics and source-oriented health risks of heavy metals in the soil and groundwater of a legacy contaminated by the chlor-alkali industry in central China.

The chlor-alkali industry (CAI) is crucial for global chemical production; however, its operation has led to widespread heavy metal (HM) contamination at numerous sites, which has not been thoroughly investigated. This study analysed 122 soil and groundwater samples from a typical CAI site in Kaifeng, China. Our aim was to assess the ecological and health risks, identify the sources, and examine the migration characteristics of HMs at this site using Monte Carlo simulation, absolute principal component score-multiple linear regression (APCS-MLR), and the potential environmental risk index (Ei). Our findings revealed that the exceedance rates for Cd, Pb, Hg, and Ni were 71.96%, 45.79%, 49.59%, and 65.42%, respectively. Mercury (Hg) displayed the greatest coefficient of variation across all the soil layers, indicating a significant anthropogenic influence. Cd and Hg were identified as having high and extremely high potential environmental risk levels, respectively. The spatial distributions of the improved Nemerow index (INI), total ecological risk (Ri), and HM content varied considerably, with the most contaminated areas typically associated with the storage of raw and auxiliary materials. Surface aggregation and significant vertical transport were noted for HMs; As and Ni showed substantial accumulation in subsoil layers, severely contaminating the groundwater. Self-organizing maps categorized the samples into two different groups, showing strong positive correlations between Cd, Pb, and Hg. The APCS-MLR model suggested that industrial emissions were the main contributors, accounting for 60.3% of the total HM input. Elevated hazard quotient values for Hg posed significant noncarcinogenic risks, whereas acceptable levels of carcinogenic risk were observed for both adults (96.60%) and children (97.83%). This study significantly enhances historical CAI pollution data and offers valuable insights into ongoing environmental and health challenges.

Accumulation of heavy metals from single and combined olive mill wastewater and pomace in soil and bioaccumulation in tissues of two earthworm species: Endogeic (Aporrectodea trapezoides) and Epigeic (Eisenia fetida).

Soil and earthworms are threatened by anthropogenic contamination resulting from olive mill waste dumping on the soil due to their pollutant properties. While several studies have explored the effects of olive mill waste on soil properties and the accumulation of heavy metals in soil, there is currently a gap in the literature regarding the potential bioaccumulation of heavy metals from olive mill waste in earthworms. In this study, soil with earthworms from two ecological categories (endogeic: Aporrectodea trapezoides and epigeic: Eisenia fetida) was treated with increasing doses of olive mill wastewater (OMWW) and olive mill pomace (OMP), applied individually or combined, in an indoor experiment in plastic containers, under laboratory conditions. The results revealed the presence of significant concentrations of heavy metals in the two types of wastes ranging as follows: Fe˃ Zn˃ Cu˃ Cd˃ Cr for OMWW, and Fe˃ Zn˃ Cu˃ Cr for OMP (with Cd below the detection limit). The study demonstrated distinct effects of OMWW and OMP, both individually and in combination, on soil heavy metal content, ranging as follows: soil OMWW > soil Combination > soil OMP for Cd; soil Combination > soil OMWW > soil OMP for Cr and Fe; and soil Combination > soil OMP > soil OMWW for Cu and Zn. Additionally, our investigation showed that both earthworm species exhibited significant uptake of these metals into their tissues, particularly the endogeic species. Interestingly, the most significant difference between species was in the accumulation of Cu, with the epigeic species accumulating significantly lower amounts.

Free water surface constructed wetlands: review of pollutant removal performance and modeling approaches.

Free water surface constructed wetlands (FWSCWs) for the treatment of various wastewater types have evolved significantly over the last few decades. With an increasing need and interest in FWSCWs applications worldwide due to their cost-effectiveness and other benefits, this paper reviews recent literature on FWSCWs' ability to remove different types of pollutants such as nutrients (i.e., TN, TP, NH4-N), heavy metals (i.e., Fe, Zn, and Ni), antibiotics (i.e., oxytetracycline, ciprofloxacin, doxycycline, sulfamethazine, and ofloxacin), and pesticides (i.e., Atrazine, S-Metolachlor, imidacloprid, lambda-cyhalothrin, diuron 3,4-dichloroanilin, Simazine, and Atrazine) that may co-exist in wetland inflow, and discusses approaches for simulating hydraulic and pollutant removal processes. A bibliometric analysis of recent literature reveals that China has the highest number of publications, followed by the USA. The collected data show that FWSCWs can remove an average of 61.6%, 67.8%, 54.7%, and 72.85% of inflowing nutrients, heavy metals, antibiotics, and pesticides, respectively. Optimizing each pollutant removal process requires specific design parameters. Removing heavy metal requires the lowest hydraulic retention time (HRT) (average of 4.78 days), removing pesticides requires the lowest water depth (average of 0.34 m), and nutrient removal requires the largest system size. Vegetation, especially Typha spp. and Phragmites spp., play an important role in FWSCWs' system performance, making significant contributions to the removal process. Various modeling approaches (i.e., black-box and process-based) were comprehensively reviewed, revealing the need for including the internal process mechanisms related to the biological processes along with plants spp., that supported by a further research with field study validations. This work presents a state-of-the-art, systematic, and comparative discussion on the efficiency of FWSCWs in removing different pollutants, main design factors, the vegetation, and well-described models for performance prediction.

2D PtRhPb Mesoporous Nanosheets with Surface-Clean Active Sites for Complete Ethanol Oxidation Electrocatalysis.

The development of active and selective metal electrocatalysts for complete ethanol oxidation reaction (EOR) into desired C1 products is extremely promising for practical application of direct ethanol fuel cells. Despite some encouraging achievements, their activity and selectivity remain unsatisfactory. In this work, it is reported that 2D PtRhPb mesoporous nanosheets (MNSs) with anisotropic structure and surface-clean metal site perform perfectly for complete EOR electrocatalysis in both three-electrode and two-electrode systems. Different to the traditional routes, a selective etching strategy is developed to produce surface-clean mesopores while retaining parent anisotropy quasi-single-crystalline structure without the mesopore-forming surfactants. This method also allows the general synthesis of surface-clean mesoporous metals with other compositions and structures. When being performed for alkaline EOR electrocatalysis, the best PtRhPb MNSs deliver remarkably high activity (7.8 A mg-1) and superior C1 product selectivity (70% of Faradaic efficiency), both of which are much better than reported electrocatalysts. High performance is assigned to multiple structural and compositional synergies that not only stabilized key OHads intermediate by surface-clean mesopores but also separated the chemisorption of two carbons in ethanol by adjacent Pt and Rh sites, which facilitate the oxidation cleavage of stable C─C bond for complete EOR electrocatalysis.

Performance and mechanistic study of biochar and magnesium-enhanced phytoremediation in cadmium-contaminated soil by alfalfa.

Recently, phytoremediation has been regarded as a green and environment friendly technique to treat metals contaminated soils. Thus, in this study, pot experiments were designed to investigate the combine effects of biochar and magnesium (MPs) to purify cadmium (Cd)-contaminated soils by Medicago sativa L. (alfalfa). The results showed that the combined use of biochar and Mg significantly increased the accumulation of Cd and promoted the transport of Cd from root to shoot in alfalfa, simultaneously. Importantly, the combined use of biochar and Mg could increase the accumulation of Cd in shoot and whole plant (shoot + root) of alfalfa up-to 59.1% and 23.1%, respectively. Moreover, the enhancement mechanism can be analyzed from several aspects. Firstly, the photosynthesis was enhanced, which was beneficial to plant growth. The product of photosynthesis provided energy for uptake and transport of Cd. Meanwhile, its transport in phloem could promote the transport of Cd. Secondly, the enhancement of antioxidant capacity of alfalfa effectively protected the membrane structure of alfalfa, which indicated that Cd could enter alfalfa from the channel on the cell membrane. Lastly, the chemical form of Cd and microbial community structure in soil were changed. Overall, these changes reduced the Cd toxicity in soil, enhanced the resistance capability of alfalfa, increased the Cd uptake by alfalfa and promoted the growth of alfalfa. Thus, the obtained results suggested that the combined use of biochar and Mg is an effective approach to enhance phytoremediation performance for purifying Cd-contaminated soils.

Adsorption performance and mechanism of pectin modified with ß-cyclodextrin for Zn2+ and Cu2.

Removing heavy metals from aqueous solutions has drawn more and more attentions these years because of their serious global health challenge to human society. To develop an adsorbent with green, stable and high-efficiency for adsorption of heavy metals, pectin ß-cyclodextrin composite was successfully prepared and used for Zn2+ and Cu2+ adsorption for the first time. Various variables that influence the adsorption performance were explored, and the optimal adsorption conditions were determined. According to the pseudo-second-order kinetic model, the adsorption process of Zn2+ and Cu2+ by the adsorbent was mainly chemical adsorption. The adsorbent adsorption process was an exothermic and non-spontaneous process. According to the Langmuir isotherm model, the maximum adsorption capacity was 12.51 ± 0.33 and 24.98 ± 0.23 mg/g for Zn2+ and Cu2+, respectively. The FTIR, EDX and XPS results revealed that the main mechanisms of removing pollutants by adsorbent were ion exchange and coordination. In addition, electrostatic attraction and chelation were present in the adsorption process. After five adsorption desorption cycles, the pectin ß-cyclodextrin composite adsorbent still exhibited adsorption and regeneration capabilities. This study provides a low-cost, effective and simple method for preparation of modified pectin, which has excellent application potential in the removal of heavy metal ions from wastewater.

Halophilic archaea as tools for bioremediation technologies.

Haloarchaea are extremophilic microorganisms belonging to the Archaea domain that require high salt concentrations to be alive, thus inhabiting ecosystems like salty ponds, salty marshes, or extremely salty lagoons. They are more abundantly and widely distributed worldwide than initially expected. Most of them are grouped into two families: Halobacteriaceae and Haloferacaceae. The extreme conditions under which haloarchaea survive contribute to their metabolic and molecular adaptations, thus making them good candidates for the design of bioremediation strategies to treat brines, salty water, and saline soils contaminated with toxic compounds such as nitrate, nitrite, oxychlorates such as perchlorate and chlorate, heavy metals, hydrocarbons, and aromatic compounds. New advances in understanding haloarchaea physiology, metabolism, biochemistry, and molecular biology suggest that biochemical pathways related to nitrogen and carbon, metals, hydrocarbons, or aromatic compounds can be used for bioremediation proposals. This review analyses the novelty of the most recent results showing the capability of some haloarchaeal species to assimilate, modify, or degrade toxic compounds for most living beings. Several examples of the role of these microorganisms in the treatment of polluted brine or salty soils are also discussed in connection with circular economy-based processes. KEY POINTS: • Haloarchaea are extremophilic microorganisms showing genuine metabolism • Haloarchaea can metabolise compounds that are highly toxic to most living beings • These metabolic capabilities are useful for designing soil and water bioremediation strategies.

Quantum acoustics unravels Planckian resistivity.

Strange metals exhibit universal linear-in-temperature resistivity described by a Planckian scattering rate, the origin of which remains elusive. By employing an approach inspired by quantum optics, we arrive at the coherent state representation of lattice vibrations: quantum acoustics. Utilizing this nonperturbative framework, we demonstrate that lattice vibrations could serve as active drivers in the Planckian resistivity phenomenon, challenging prevailing theories. By treating charge carriers as quantum wave packets negotiating the dynamic acoustic field, we find that a competition ensues between localization and delocalization giving rise to the previously conjectured universal quantum bound of diffusion, [Formula: see text], independent of temperature or any other material parameters. This leads to the enigmatic T-linear resistivity over hundreds of degrees, except at very low temperatures. Quantum diffusion also explains why strange metals have much higher electrical resistivity than typical metals. Our work elucidates the critical role of phonons in Planckian resistivity from a unique perspective and reconsiders their significance in the transport properties of strange metals.

Syntheses of heterometallic organic frameworks catalysts via multicomponent postmodification: For improving CO2 photoreduction efficiency.

To enhance the economic viability of photocatalytic materials for carbon capture and conversion, the challenge of employing expensive photosensitizer must be overcome. This study aims to improve the visible light utilization with zirconium-based metal-organic frameworks (Zr-MOFs) by employing a multi-component post-synthetic modification (PSM) strategy. An economical photosensitiser and copper ions are introduced into MOF 808 to enhance its photoreduction properties. Notably, the PSM of MOF 808 shows the highest CO yield up to 236.5 µmol g-1 h-1 with aHCOOH production of 993.6 µmol g-1 h-1 under non-noble metal, and its mechanistic insight for CO2 reaction is discussed in detail. The research results have important reference value for the potential application of photocatalytic metal-organic frameworks.