A Dynamic Window Method Based on Reinforcement Learning for SSVEP Recognition.

Steady-state visual evoked potential (SSVEP) is one of the most used brain-computer interface (BCI) paradigms. Conventional methods analyze SSVEPs at a fixed window length. Compared with these methods, dynamic window methods can achieve a higher information transfer rate (ITR) by selecting an appropriate window length. These methods dynamically evaluate the credibility of the result by linear discriminant analysis (LDA) or Bayesian estimation and extend the window length until credible results are obtained. However, the hypotheses introduced by LDA and Bayesian estimation may not align with the collected real-world SSVEPs, which leads to an inappropriate window length. To address the issue, we propose a novel dynamic window method based on reinforcement learning (RL). The proposed method optimizes the decision of whether to extend the window length based on the impact of decisions on the ITR, without additional hypotheses. The decision model can automatically learn a strategy that maximizes the ITR through trial and error. In addition, compared with traditional methods that manually extract features, the proposed method uses neural networks to automatically extract features for the dynamic selection of window length. Therefore, the proposed method can more accurately decide whether to extend the window length and select an appropriate window length. To verify the performance, we compared the novel method with other dynamic window methods on two public SSVEP datasets. The experimental results demonstrate that the novel method achieves the highest performance by using RL.

Nonlinear responses of biofilm bacteria to alkyl-chain length of parabens by DFT calculation.

Parabens can particularly raise significant concerns regarding the disruption of microbial ecology due to their antimicrobial properties. However, the responses of biofilm bacteria to diverse parabens with different alkyl-chain length remains unclear. Here, theoretical calculations and bioinformatic analysis were performed to decipher the influence of parabens varying alkyl-chain lengths on the biofilm bacteria. Our results showed that the disturbances in bacterial community did not linearly response to the alkyl-chain length of parabens, and propylparaben (PrP), with median chain length, had more severe impact on bacterial community. Despite the fact that paraben lethality linearly increased with chain length, the PrP had a higher chemical reactions potential than parabens with shorter or longer alkyl-chain. The chemical reactions potential was critical in the nonlinear responses of bacterial community to alkyl-chain length of parabens. PrP could impose selective pressure to disturb the bacterial community, because it had a more profound contribution to deterministic assembly process. Furthermore, N-acyl-homoserine lactones was also significantly promoted under PrP exposure, confirming that PrP could affect the bacterial community by influencing the quorum-sensing system. Overall, our study reveals the nonlinear responses of bacterial communities to the alkyl-chain lengths of parabens and provides insightful perspectives for the better regulation of parabens. ENVIRONMENTAL IMPLICATION: Parabens are recognized as emerging organic pollutants, which specially raise great concerns due to their antimicrobial properties disturbing microbial ecology. However, few study have addressed the relationship between bacterial community responses and the molecular structural features of parabens with different alkyl-chain length. This investigation revealed nonlinear responses of the bacterial community to the alkyl-chain length of parabens through DFT calculation and bioinformatic analysis and identified the critical roles of chemical reactions potential in nonlinear responses of bacterial community. Our results benefit the precise evaluation of ecological hazards posed by parabens and provide useful insights for better regulation of parabens.

Revealing bioresponses of biofilm and flocs to salinity gradient in halophilic biofilm reactor.

Understanding the different biological responses to salinity gradient between coexisting biofilm and flocs is crucial for regulating the ecological function of biofilm system. This study investigated performance, dynamics, and community assembly of biofilm system under 3 %-7% salinity gradient. The removal efficiency of NH4+-N remained stable and exceeded 93 % at 3 %-6% salinity, but decreased to below 80 % at 7 % salinity. The elevated salinity promoted the synthesis of extracellular polymer substrates, inhibited microbial respiration, and significantly regulated the microbial community structure. Compared to flocs, biofilm exhibited greater species diversity and richer Nitrosomonas. It was found diffusion limitations dominated the microbial community assembly under the salinity gradient. And microbial network revealed positive interactions predominated the microbial relationships, designating norank Spirochaetaceae, unclassified Micrococcales, Corynebacterium, and Pusillimonas as keystone species. Moreover, distinct salinity preferences in nitrogen transformation-related genes were observed. This study can improve the understanding to the regulation of biofilm systems to salt stresses.

Recovery mechanism of heterotrophic ammonia assimilation system under chromium hexavalent stress.

Heterotrophic ammonia assimilation (HAA), an innovative technology for high-salinity wastewater treatment, demonstrates self-recovery capability following Cr (VI) stress. This study investigated the inhibitory effects and self-restoration mechanisms of Cr (VI) at various stress levels. The removal efficiencies of NH4+-N and Cr (VI) in the HAA gradually decreased with increasing influent Cr (VI) concentration. Exposure to Cr (VI) increased the amounts of high-molecular-weight proteins in soluble microbial products and stimulated the generation of extracellular polymeric substances. Heterotrophic functional microorganisms with Cr (VI) tolerance, such as Marinobacter and Planktosalinus, were enriched. An assimilation pathway gene (glnA) and a Cr (VI)-related gene (atoB) were also upregulated. After ceasing Cr (VI) addition, the HAA system demonstrated a 17.1 % increase in the removal efficiency of NH4+-N, which was attributable to its self-recovery ability. This study provides a scientific and theoretical foundation for the HAA process in resisting the impact of heavy-metal-containing wastewater and self-recovery.

Nutrients recovery by coupled bioreactor of heterotrophic ammonia assimilation and microbial fuel cell in saline wastewater.

Heterotrophic ammonia assimilation (HAA) process had been widely used in the treatment of high salt wastewater, but the electro enhanced coupling process and electron transfer process were rarely studied. In this study, a HAA process coupled microbial fuel cell (MFC) system was established to treat ammonia-containing wastewater under increasing salinity to achieve nitrogen recovery and electricity generation. Up to 95.4 % NH4+-N and 96.4 % COD removal efficiencies were achieved at 2 % salinity in HAA-MFC. The maximum power density and current density at 2 % salinity were 29.93 mW/m2 and 182.37 mA/m2, respectively. The residual organic matter in the cathode effluent was effectively removed by the anode. The increase of salinity not only enhanced the sludge settling performance and activity, but also promoted the enzyme activity and amino acid production of the ammonia assimilation pathway. Marinobacter and Halomonas were gradually enriched at the anode and cathode with increased salinity to promote ammonia assimilation and electron production. This research offered a promising solution to overcome salinity-related challenges in wastewater treatment and resource recovery.

Sulfur-containing iron carbon nanocomposites activate persulfate for combined chemical oxidation and microbial remediation of petroleum-polluted soil.

In this study, sulfur-containing iron carbon nanocomposites (S@Fe-CN) were synthesized by calcining iron-loaded biomass and utilized to activate persulfate (PS) for the combined chemical oxidation and microbial remediation of petroleum-polluted soil. The highest removal efficiency of total petroleum hydrocarbons (TPHs) was achieved at 0.2% of activator, 1% of PS and 1:1 soil-water ratio. The EPR and quenching experiments demonstrated that the degradation of TPHs was caused by the combination of 1O2,·OH, SO4·-, and O2·-. In the S@Fe-CN activated PS (S@Fe-CN/PS) system, the degradation of TPHs underwent two phases: chemical oxidation (days 0 to 3) and microbial degradation (days 3 to 28), with kinetic constants consistent with the pseudo-first-order kinetics of chemical and microbial remediation, respectively. In the S@Fe-CN/PS system, soil enzyme activities decreased and then increased, indicating that microbial activities were restored after chemical oxidation under the protection of the activators. The microbial community analysis showed that the S@Fe-CN/PS group affected the abundance and structure of microorganisms, with the relative abundance of TPH-degrading bacteria increased after 28 days. Moreover, S@Fe-CN/PS enhanced the microbial interactions and mitigated microbial competition, thereby improving the ability of indigenous microorganisms to degrade TPHs.

Carbon nanoparticles neutralize carbon dioxide (CO2) in cytotoxicity: Potent carbon emission induced resistance to anticancer nanomedicine and antibiotics.

Excessive carbon emissions, especially CO2 release, have been a global concern. Few studies applied nanotechnology to relieve the ecotoxicity of CO2. Here, we applied carbon dots (CDs) to neutralize the CO2. We found CO2 induced the aggregation of CDs, which is of significance for CDs in enhanced fluorescence intensity but decreased CDs function in nanozyme activity, and reduced CDs toxicity to bacteria and cancer cells. Our data suggest the concern of CO2 release in global health in CDs mediated anticancer drug delivery and antibiotics resistance. However, enhanced fluorescence in cells which can be applied for bioimaging or CO2 sensing as simulated investigation by static charged attraction of positively charged CDs with negatively charged soluble HCO3-. Thus, CO2 abrogates the nanomedicine efficacy in cancer cells and antibacterial and may induce drug resistance for patients undergoing chemotherapy or antibiotics therapy. To overcome the resistance, we may apply the CDs for a neutralization of CO2 for impact on anticancer nanomedicine and antibiotics and reducing the ecotoxicity in biological systems.

Novel strategy for treating high salinity oilfield produced water: Pyrite-activated peroxymonosulfate coupled with heterotrophic ammonia assimilation.

Existing conventional biological treatment techniques face numerous limitations in effectively removing total petroleum hydrocarbons (TPHs) and ammonia (NH4+-N) from oilfield-produced water (OPW), highlighting the pressing need for innovative pre-oxidation and biological treatment processes. In this study, a pyrite-activated peroxymonosulfate (PMS)-coupled heterotrophic ammonia assimilation (HAA) system was established to achieve satisfactory system performance for OPW treatment. Pyrite sustained-release Fe2+-activated PMS was used to produce SO4•- and •OH, and 71.0 % of TPHs were effectively removed from the oil wastewater. The average TPHs and NH4+-N removal efficiencies in the test group with pre-oxidation were 96.9 and 98.3 %, compared to 46.5 and 77.1 % in the control group, respectively. The maximum fluorescence intensities of tryptophan protein and aromatic protein in the test group declined by 83.7 %. Fourier transform ion cyclotron resonance mass spectrometry revealed that pre-oxidation degraded more long-chain hydrocarbons and aromatic family compound, whereas the HAA process produced more proteins and carbohydrates. Pyrite-PMS promoted the enrichment of ammonia-assimilating bacteria, alleviating the explosive increase in extracellular polymeric substances and reducing sludge settleability. The low cost, efficiency, green chemistry principles, and synergies of this approach make it a powerful solution for practical OPW treatment to reduce environmental impacts and promote sustainable wastewater treatment.

Improving soil phosphorus availability in saline areas by marine bacterium Bacillus paramycoides.

The utilization of phosphate-solubilizing bacteria (PSB) in agriculture has long been proposed as an eco-friendly method to enhance soil phosphorus (P) availability, thereby reducing reliance on chemical P fertilizers. However, their application in saline soils is challenged by salt-induced stress on common PSB strains. In this study, we sourced bacterial strains from marine environments, aiming to identify robust PSB strains adaptable to saline conditions and assess their potential as P bio-fertilizers through a microcosm experiment. Our findings indicate that the inoculation of a selected marine PSB, Bacillus paramycoides 3-1a, increased soil available P content by 12.5% when applied alone and by 61.2% when combined with organic amendments. This enhancement results from improved inorganic P solubilization and organic P mineralization in soils. Additionally, these treatments raised soil nitrogen levels, reshaped microbial community structures, and significantly enhanced wheat (Triticum aestivum L.) growth, with P accumulation increasing by 24.2-40.9%. Our results underscore the potential of marine PSB in conjunction with organic amendments for the amelioration of saline agricultural soils.

Enhanced degradation of petroleum in saline soil by nitrogen stimulation and halophilic emulsifying bacteria Bacillus sp. Z-13.

Remediation of petroleum-contaminated soil is a widely concerned challenge. As an ecofriendly method, the performance improvement of indigenous microbial degradation is facing the bottleneck. In this study, a strain with high efficiency of petroleum degradation was isolated from the petroleum-contaminated soil and identified and named as Bacillus sp. Z-13. The strain showed the ability to produce lipopeptide surfactant which could improve 66% more petroleum hydrocarbons eluted. Strain Z-13 and its biosurfactant exhibited broad environmental adaptability to salinity (0-8%), pH (6-9) and temperature (15-45 °C). With the addition of strain Z-13 and the stimulation of NH4Cl, up to 59% of the petroleum in the contaminated soil was removed at the carbon to nitrogen ratio of 10. Microbial community analysis showed that petroleum-degrading bacteria, represented by Bacillus, became the dominant species at genus level and played an important role in the remediation. Additionally, ammonium stimulation facilitated both pathways of ammonium assimilation and nitrification in native microorganisms to achieve efficient degradation of petroleum hydrocarbons. This study could provide a promising approach for stable, environmental-friendly and efficient remediation of petroleum-contaminated soil.

A review of microbial nitrogen transformations and microbiome engineering for biological nitrogen removal under salinity stress.

The osmotic stress caused by salinity exerts severe inhibition on the process of biological nitrogen removal (BNR), leading to the deterioration of biosystems and the discharge of nitrogen with saline wastewater. Feasible strategies to solve the bottleneck in saline wastewater treatment have attracted great attention, but relevant studies to improve nitrogen transformations and enhance the salt-tolerance of biosystems in terms of microbiome engineering have not been systematically reviewed and discussed. This work attempted to provide a more comprehensive explanation of both BNR and microbiome engineering approaches for saline wastewater treatment. The effect of salinity on conventional BNR pathways, nitrification-denitrification and anammox, was summarized at cellular and metabolic levels, including the nitrogen metabolic pathways, the functional microorganisms, and the inhibition threshold of salinity. Promising nitrogen transformations, such as heterotrophic nitrification-aerobic denitrification, ammonium assimilation and the coupling of conventional pathways, were introduced and compared based on advantages and challenges in detail. Strategies to improve the salt tolerance of biosystems were proposed and evaluated from the perspective of microbiome engineering. Finally, prospects of future investigation and applications on halophilic microbiomes in saline wastewater treatment were discussed.

Responses of halophilic microbial communities to changes in salt composition: Comparison between autotrophic nitrification and heterotrophic ammonia assimilation biosystems.

The concentration and proportion of chlorine (Cl-) and sulfate ions (SO42-) in actual high salinity wastewater exhibit significant fluctuations due to their diverse sources. This study compared the response of halophilic autotrophic nitrification (AN) and heterotrophic ammonia assimilation (HAA) sludges to changes in salt composition. The results demonstrated that both the AN and HAA systems maintained high ammonia removal efficiency even when exposed to mixed salt ions or pure sulfate conditions. Increasing the concentration of SO42- resulted in an increase in extracellular polymeric substances content, sludge settleability, sludge hydrophobicity, and the relative abundance of Nitrosomonas in the AN system (from 2.3% to 10.4%). The dominant heterotrophic bacteria in the HAA system underwent turnover in response to changes in salt composition conditions. The robustness and the cooperation between microorganisms of the HAA system surpassed those of the AN system. This study provides scientific foundation for treating multi-ion high salinity wastewater.

Integrated application of phosphorus-accumulating bacteria and phosphorus-solubilizing bacteria to achieve sustainable phosphorus management in saline soils.

The challenge of managing agricultural phosphorus (P) in saline regions entails both reducing leaching for environmental protection and maintaining soil available P levels for crop production, which could be achieved through functional microorganisms that can facilitate P transformation processes like P assimilation, inorganic P solubilization, and organic P mineralization. In this study, we proposed an integrated utilization of phosphorus-accumulating bacteria (PAB) and phosphorus-solubilizing bacteria (PSB) to reach the goal of alleviating P leaching while improving soil available P levels. The study conducted a microcosm experiment that combined a soil column test, soil incubation, and pot experiment to evaluate the effect of bacterial inoculants on soil P leaching, soil P availability, and plant P accumulation. The results showed that the application of PAB reduced 22.6 % of dissolved P leaching through the absorption of labile phosphate in the soil, and 17.3 % of particulate P leaching through the promoted soil aggregation. The integrated inoculation of PSB and PAB synergistically improved soil available P content by 18.3 % through the mineralization of soil organic P, and remarkably boosted wheat growth and its P accumulation. Microbial community analysis revealed that the integrated microbial treatment decreased the diversity of soil bacterial community and increased the abundance of native microbial species, i.g. Lysobacter and Ramlibacter, which were positively correlated with soil available P content and alkaline phosphatase level. In conclusion, the integrated microbial strategy based on halotolerant PAB and PSB has great potential for sustainable P management in saline areas and agricultural activities.

Enhanced phytoremediation of petroleum-contaminated soil by biochar and urea.

Application of bioremediation in petroleum-contaminated soils is limited by its low efficiency. Although biochar and urea are commonly used soil additives, their potential beneficial effect on the bioremediation of petroleum contamination have rarely been discussed. In this study, biochar and urea were combined to test their effects on the phytoremediation of petroleum-contaminated soil in pot experiments. Our results showed that the degradation rate of total petroleum hydrocarbons reached 49.6%, 38.3%, 42.5%, and 77.9% when the soil was treated with biochar, urea, ryegrass, and their integrated application treatment (PBCN), respectively. A number of soil physicochemical properties (e.g., pH, elements, aggregate distribution, and organic matter composition) altered by the treatments were found to be linked to the accelerated degradation of petroleum hydrocarbons. The activities of soil dehydrogenase, lipase, and urease, and the abundances of 16 s rRNA gene and alkane degradation-related genes could be increased simultaneously when biochar, urea, and ryegrass were co-applied. Furthermore, urea significantly reduced soil bacterial α-diversity, while soil bacterial community dissimilation was mainly driven by urea and ryegrass. Lysobacter, xanthomonadaceae, and longimicrobia could be biomarker species in the PBCN group. Soil bacterial network analysis showed that biochar and urea application decreased the network complexity and robustness, while ryegrass behaved inversely. Lastly, soil metabolomic analysis revealed that root soil metabolites were greatly affected by urea-addition during phytoremediation, and co-application of biochar and urea could activate the putative metabolism pathway of petroleum hydrocarbons in root soil (e.g., naphthalene and anthracene degradation, and pyruvate metabolism). In summary, this study confirmed the enhancement of biochar and urea application in the phytoremediation of petroleum-contaminated soil and explored the internal mechanism of the interactive effect, which can potentially improve the development of eco-friendly and cost-effective in-situ bioremediation technology for petroleum-contaminated soils.

Revealing the Generation of High-Valent Cobalt Species and Chlorine Dioxide in the Co3O4-Activated Chlorite Process: Insight into the Proton Enhancement Effect.

A Co3O4-activated chlorite (Co3O4/chlorite) process was developed to enable the simultaneous generation of high-valent cobalt species [Co(IV)] and ClO2 for efficient oxidation of organic contaminants. The formation of Co(IV) in the Co3O4/chlorite process was demonstrated through phenylmethyl sulfoxide (PMSO) probe and 18O-isotope-labeling tests. Both experiments and theoretical calculations revealed that chlorite activation involved oxygen atom transfer (OAT) during Co(IV) formation and proton-coupled electron transfer (PCET) in the Co(IV)-mediated ClO2 generation. Protons not only promoted the generation of Co(IV) and ClO2 by lowering the energy barrier but also strengthened the resistance of the Co3O4/chlorite process to coexisting anions, which we termed a proton enhancement effect. Although both Co(IV) and ClO2 exhibited direct oxidation of contaminants, their contributions varied with pH changes. When pH increased from 3 to 5, the deprotonation of contaminants facilitated the electrophilic attack of ClO2, while as pH increased from 5 to 8, Co(IV) gradually became the main contributor to contaminant degradation owing to its higher stability than ClO2. Moreover, ClO2- was transformed into nontoxic Cl- rather than ClO3- after the reaction, thus greatly reducing possible environmental risks. This work described a Co(IV)-involved chlorite activation process for efficient removal of organic contaminants, and a proton enhancement mechanism was revealed.

Nitrogen recovery from wastewater by microbial assimilation - A review.

The increased nitrogen (N) input with low utilization rate in artificial N management has led to massive reactive N (Nr) flows, putting the Earth in a high-risk state. It is essential to recover and recycle Nr during or after Nr removal from wastewater to reduce N input while simultaneously mitigate Nr pollution in addressing the N stress. However, mechanisms for efficient Nr recovery during or after Nr removal remain unclear. Here, the occurrence of N risk and progress in wastewater treatment in recent years as well as challenges of the current technologies for N recovery from wastewater were reviewed. Through analyzing N conversion fluxes in biogeochemical N-cycling networks, microbial N assimilation through photosynthetic and heterotrophic microorganisms was highlighted as promising alternative for synergistic N removal and recovery in wastewater treatment. In addition, the prospects and gaps of Nr recovery from wastewater through microbial assimilation are discussed.

A L1 normalization enhanced dynamic window method for SSVEP-based BCIs.

BACKGROUND: Filter bank canonical correlation analysis (FBCCA) has been widely applied to detect the frequency components of steady-state visual evoked potential (SSVEP). FBCCA with dynamic window (FBCCA-DW) is recently proposed to improve its performance. FBCCA-DW adaptively chooses a proper window length based on the signal-to-noise ratio (SNR) of SSVEP signals. It takes the output of FBCCA to evaluate the SNR of SSVEP signals, by using the softmax function and cost function. In practice, SSVEP signals always contain task-unrelated electroencephalogram (EEG), which degrades the SSVEP task. When the power of task-unrelated EEG changes, there would be an offset in the output of FBCCA. However, due to the insensitivity of softmax function to the offset, the SNR in FBCCA-DW ignores the interference of the task-unrelated EEG. Therefore, FBCCA-DW will analyze SSVEP signals at an inappropriate window length. NEW METHOD: To solve the issue, we replace the softmax function with the L1 normalization, which could respond a reasonable SNR to the offset. Since the proposed method takes task-unrelated EEG into account, it could choose a more appropriate window length. RESULTS: We comprehensively validate the proposed method on three publicly available SSVEP datasets. The results indicate that the proposed method could improve the performance significantly. COMPARISON WITH EXISTING METHODS: The proposed method outperforms FBCCA and FBCCA-DW in terms of information transfer rate (ITR). CONCLUSIONS: The proposed method enhances the correlation between the window length and the credibility of the recognition result. It shows its potential for practical applications in complex environments.

Cooperation of heterotrophic bacteria enables stronger resilience of halophilic assimilation biosystem than nitrification system under long-term stagnation.

Long-term stagnation of biosystems (with no or very little wastewater) owing to seasonal downtime or failure maintenance brings great challenges to the performance recovery after system restart. In particular, the reduction of microbial activity and change of dissolved organic matter (DOM) affect the effluent quality and subsequent treatment procedures. Monitoring the dynamics and resilience of biosystems after long-term stagnation is important to formulate targeted countermeasures for system stability. However, the influence of long-term stagnation on autotrophic nitrification (AN) and heterotrophic assimilation (HA) biosystems has not been systematically explored. Here, we used halophilic AN and HA systems to study the stability and resilience of two nitrogen removal consortia after long-term stagnation. The results showed that 97.5 % and 93 % of ammonium and 47.0 % and 90.1 % of total nitrogen were removed using the halophilic AN and HA systems, respectively, in the stable period. After four weeks of stagnation, the HA system showed stronger resilience than AN system, in terms of faster recovery of treatment performance, and less fluctuations in sludge settleability and extracellular polymeric substances. In addition, after the stagnation period, the DOM of AN system was rich in low-molecular refractory humic acid, whereas that of HA system was rich in high-molecular proteins. The stagnation period led to the replacement of the dominant heterotrophic functional microorganisms, Paracoccus and Halomonas, with Muricauda and Marinobacterium in the HA system. The microbial network results revealed that the cooperation of heterotrophic bacteria enables stronger resilience of the HA system from prolonged stagnation than the AN system. In addition, the nitrogen removal efficiency, protein to polysaccharide ratio of EPS and fluorescence intensity of DOM were significantly correlated with the microbial community composition. These results suggest that AN system has greater risks in terms of treatment performance and sludge stability than the system after long-term stagnation.

Visible-Light Photocatalytic Chlorite Activation Mediated by Oxygen Vacancy Abundant Nd-Doped BiVO4 for Efficient Chlorine Dioxide Generation and Pollutant Degradation.

Visible-light photocatalytic chlorite activation has emerged as an efficient oxidation process for micropollutant elimination. However, the in-depth mechanism of chlorite activation is not understood. In this study, using neodymium-doped bismuth vanadate (NdxBi1-xVO4-δ) as a model catalyst, we describe the oxygen vacancy (OV)-mediated chlorite activation process for efficient ClO2 generation and cephalexin (CPX) degradation. DFT calculations and in situ DRIFTS suggest that the OV-introduced surface -OH serves as the Brønsted acidic center for chlorite adsorption. The OV-mediated chlorite activation involves multistep reactions that surface hydroxylation and proton transfer from the surface -OH to chlorite, forming metastable chlorous acid (HClO2) and further disproportionating to ClO2. As compared with vis-photocatalysis, the vis-photocatalysis coupled with chlorite activation (vis/chlorite) technique exhibits superior performance in antibiotic degradation and achieves efficient microorganism inactivation. This work uncovers the role of OVs on chlorite activation and provides a rational strategy for designing visible-light-driven oxidation techniques in water and wastewater treatment.

Biomass hydrogels combined with carbon nanotubes for water purification via efficient and continuous solar-driven steam generation.

Solar vapor generation is a promising, environmentally friendly solution for water purification. The development and design of new materials and supporting devices for efficient energy conversion and clean water production are essential for the practical application of solar-driven desalination and water purification. In this study, an environmentally friendly and economical biomass hydrogel-based solar evaporator with a controllable shape was developed in a simple method by integrating carbon nanotubes (CNTs) into a sodium alginate (SA) hydrogel network. The evaporator had a high solar absorption rate (94.3%) and satisfactory hydrophilicity and could effectively avoid salt crystallization during the desalination process. This study took advantage of the aforementioned merits, and a high evaporation rate of 1.699 kg m-2 h-1 and a conversion efficiency of 86% were achieved under 1.0 sun irradiation. The evaporator could efficiently remove Na+, K+, Ca2+, and Mg2+ from seawater with a removal rate of up to 99.3% and a good decolorization effect on methylene blue (MB) and methyl orange (MO) dye wastewater, whose colour could be completely removed. This study provides a simple, practical, and economical method to prepare hydrogel-based evaporators that utilize abundant solar energy for large-scale desalination and wastewater treatment.