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Sludge solubilization is known as a rate-limiting step of anaerobic digestion. Although radio frequency (RF) has been applied for sludge pretreatment due to its similar thermal effect as microwave, the potential non-thermal effects of RF treatment remain controversial. In this study, we demonstrate that RF pretreatment enhances the solubilization and lysis of sludge by 8.02%-19.69% through both thermal and non-thermal mechanisms with less energy input. Scanning electron microscope images provide direct evidence that RF-induced microcurrents penetrated bacterial cells, leading to the release of intracellular substances through formed pores. Additionally, the non-thermal effect of RF treatment which could weaken the cell protection and accelerate the lysis rate involves the disruption of binding forces between extracellular polymeric substances and microbial cells. On average, the utilization of RF at a frequency of 27.12 MHz demonstrates its efficacy as a sludge pretreatment technique, as evidenced by a 13.39% reduction in energy consumption and a 16.9% improvement in treatment performance compared to conductive heating (CH). The findings of this study elucidate the possible mechanism of RF treatment of sludge and could establish a theoretical basis for the practical application of RF treatment in sludge management.
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Glioma is the most common primary intracranial tumor in adults, with high incidence, recurrence, and mortality rates. Tumor-associated neutrophils (TANs) are essential components of the tumor microenvironment (TME) in glioma and play a crucial role in glioma cell proliferation, invasion and proneural-mesenchymal transition. Besides the interactions between TANs and tumor cells, the multi-dimensional crosstalk between TANs and other components within TME have been reported to participate in glioma progression. More importantly, several therapies targeting TANs have been developed and relevant preclinical and clinical studies have been conducted in cancer therapy. In this review, we introduce the origin of TANs and the functions of TANs in malignant behaviors of glioma, highlighting the microenvironmental regulation of TANs. Moreover, we focus on summarizing the TANs-targeted methods in cancer therapy, aiming to provide insights into the mechanisms and therapeutic opportunities of TANs in the malignant glioma microenvironment.
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Neoplasias Encefálicas , Glioma , Neutrófilos , Microambiente Tumoral , Humanos , Microambiente Tumoral/fisiologia , Microambiente Tumoral/imunologia , Glioma/patologia , Glioma/terapia , Glioma/imunologia , Neutrófilos/patologia , Neutrófilos/imunologia , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/terapia , Neoplasias Encefálicas/imunologia , AnimaisRESUMO
BACKGROUND AND AIMS: CircRNAs and autophagy are closely involved in the physiological and pathological processes of ovarian cancer; however, their exact mechanisms are still undetermined. This investigation aimed to elucidate the function and associated pathways of circFAM188A, which modulates proliferation, autophagy, and invasion in ovarian cancer (EOC). METHODS: The expression of circFAM188A in the tissues of EOC patients was assessed via RT-PCR. To elucidate proliferation, invasion, and autophagy in the tumor cells, Transwell, 5-ethynyl-2'-deoxyuridine (EdU), and mRFP-GFP-LC3 reporter assays were conducted. The binding sites between circ-FAM188A and the miR-670-3p, miR-670-3p and YY1 were predicted using bioinformatics and verified by dual-luciferase reporter assays. Pulldown assays demonstrated binding between ULK1 and circ-FAM188A. ULK1 was found to be crucial in the initial stage of autophagy. Moreover, an in vivo xenograft model was established by subcutaneous injection of nude mice with EOC cells. RESULT: Expression of circ-FAM188A was increased in EOC tissues relative to normal ovarian tissues and circ-FAM188A overexpression promoted proliferation, invasion, and autophagy; these effects were reversed by circ-FAM188A silencing. miR-670-3p and circ-FAM188A co-localized in the cytoplasm. circ-FAM188A enhanced YY1 expression by sponging miR-670-3p and was also shown to interact with ULK1. CONCLUSION: It is thus suggested that circ-FAM188A modulates autophagy by sponging miR-670-3p as well as interacting with ULK1.
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Proteína Homóloga à Proteína-1 Relacionada à Autofagia , Autofagia , Carcinoma Epitelial do Ovário , Proliferação de Células , Regulação Neoplásica da Expressão Gênica , Peptídeos e Proteínas de Sinalização Intracelular , Camundongos Nus , MicroRNAs , Neoplasias Ovarianas , RNA Circular , Humanos , Proteína Homóloga à Proteína-1 Relacionada à Autofagia/metabolismo , Proteína Homóloga à Proteína-1 Relacionada à Autofagia/genética , Feminino , MicroRNAs/genética , Autofagia/genética , Carcinoma Epitelial do Ovário/genética , Carcinoma Epitelial do Ovário/patologia , Carcinoma Epitelial do Ovário/metabolismo , Animais , Camundongos , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/patologia , Neoplasias Ovarianas/metabolismo , Proliferação de Células/genética , RNA Circular/genética , RNA Circular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Linhagem Celular Tumoral , Fator de Transcrição YY1/genética , Fator de Transcrição YY1/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto , Movimento Celular/genética , Pessoa de Meia-IdadeRESUMO
The Cas3 nuclease is utilized by canonical type I CRISPR-Cas systems for processive target DNA degradation, while a newly identified type I-F CRISPR variant employs an HNH nuclease domain from the natural fusion Cas8-HNH protein for precise target cleavage both in vitro and in human cells. Here, we report multiple cryo-electron microscopy structures of the type I-F Cas8-HNH system at different functional states. The Cas8-HNH Cascade complex adopts an overall G-shaped architecture, with the HNH domain occupying the C-terminal helical bundle domain (HB) of the Cas8 protein in canonical type I systems. The Linker region connecting Cas8-NTD and HNH domains adopts a rigid conformation and interacts with the Cas7.6 subunit, enabling the HNH domain to be in a functional position. The full R-loop formation displaces the HNH domain away from the Cas6 subunit, thus activating the target DNA cleavage. Importantly, our results demonstrate that precise target cleavage is dictated by a C-terminal helix of the HNH domain. Together, our work not only delineates the structural basis for target recognition and activation of the type I-F Cas8-HNH system, but also guides further developments leveraging this system for precise DNA editing.
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BACKGROUND: Acute lymphoblastic leukemia is the most common pediatric malignancy, characterized by fever, anemia, hemorrhage, and symptoms brought on by blasts infiltrating organs. CASE PRESENTATION: This is a case report of a 9-year-old Asian patient with acute lymphoblastic leukemia who presented with polyuria alone as a presenting feature without any other clinical manifestation; primary renal disease or inherited metabolic disease was highly suspected. However, the water deprivation test and water deprivation pressurization test suggested nephrogenic diabetes insipidus, and the renal biopsy displayed diffuse lymphocytic infiltration in the renal interstitium. Bone marrow aspiration was performed immediately, and a comprehensive diagnosis of B-lymphoblastic leukemia was finally made. CONCLUSIONS: Renal infiltration with leukemic blasts mostly remains asymptomatic, but our case suggests that it can present with nephrogenic diabetes insipidus. This case fully demonstrates that the presentation of extramedullary infiltration in acute lymphoblastic leukemia is varied. When the patient has renal diabetes insipidus as the first symptom, the possibility of hematological tumor infiltration should be considered when finding the cause, and timely bone marrow cytology should be performed.
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Diabetes Insípido Nefrogênico , Leucemia-Linfoma Linfoblástico de Células Precursoras , Humanos , Criança , Diabetes Insípido Nefrogênico/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras/complicações , Leucemia-Linfoma Linfoblástico de Células Precursoras/diagnóstico , Masculino , Poliúria/etiologia , Infiltração Leucêmica/diagnóstico , Rim/patologia , Medula Óssea/patologiaRESUMO
Sludge pretreatment plays a crucial role in solubilizing particulate matters to release organic matter for subsequent anaerobic fermentation (AF). This study innovatively combines radio frequency (RF) heating and alkaline treatment, and finds that the combined pretreatment achieved a sludge disintegration rate of 35.11 %, which is 15.19 % and 8.48 % higher than single RF or alkaline pretreatment. The dissociated ions from the alkali are conducive to RF action on sludge. Furthermore, the combined pretreatment significantly benefits the subsequent AF experiments, resulting in a 9-fold increase in volatile fatty acids production. Considering cost-effectiveness, the optimal operating condition is a 10-minute RF treatment at pH 10 with a total cost of 4.35 × 10-3 dollars per kg soluble chemical oxygen demand (SCOD) increased. These findings provide a foundational basis for the development of a novel technology for sludge pretreatment.
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Ácidos Graxos Voláteis , Fermentação , Esgotos , Anaerobiose , Ondas de Rádio , Concentração de Íons de Hidrogênio , Álcalis/farmacologia , Análise da Demanda Biológica de Oxigênio , Calefação , Temperatura AltaRESUMO
BACKGROUND: Self-renewal of glioma stem cells (GSCs) is responsible for glioblastoma (GBM) therapy-resistant and recurrence. Tumor necrosis factor α (TNFα) and TNF signaling pathway display an antitumor activity in preclinical models and in tumor patients. However, TNFα exhibits no significance for glioma clinical prognosis based on Glioma Genome Atlas database. This study aimed to explore whether TNFα of tumor microenvironment maintains self-renewal of GSCs and promotes worse prognosis in glioma patient. METHODS: Spatial transcriptomics, immunoblotting, sphere formation assay, extreme limiting dilution, and gene expression analysis were used to determine the role of TNFα on GSC's self-renewal. Mass spectrometry, RNA-sequencing detection, bioinformatic analyses, qRT-RNA, immunofluorescence, immunohistochemistry, single cell RNA sequencing, in vitro and in vivo models were used to uncover the mechanism of TNFα-induced GSC self-renewal. RESULTS: Low level of TNFα displays a promoting effect on GSC self-renewal and worse glioma prognosis. Mechanistically, Vasorin (VASN) mediated TNFα-induced self-renewal by potentiating glycolysis. Lactate produced by glycolysis inhibits the TNFα secretion of tumor-associated macrophages (TAMs) and maintains TNFα in a low level. CONCLUSIONS: TNFα-induced GSC self-renewal mediated by VASN provides a possible explanation for the failures of endogenous TNFα effect on GBM. Combination of targeting VASN and TNFα anti-tumor effect may be an effective approach for treating GBM.
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Butterflies constitute approximately 10% of lepidopteran insects, and along with silkworms, they can produce silk; however, this feature is often ignored. In the present study, we observed two primary methods used by butterflies to hang pupae on trees using silk: pupa adheraena (Danaus chrysippus) and pupa contigua (Papilio polytes). Anchoring the abdominal ends of pupae with a silk pad was the most common method used in both cases, whereas wrapping silk around the body using a silk girdle was a method unique to pupa contigua. The connection between the cremaster and silk pad was observed to be similar to that between the hook and loop of a Velcro fastener, except that the cremaster hook is anchor-shaped rather than being a single hook. Such a connection will remain secure, ensuring the safety of the pupae during exposure to wind and rain. Through determining the mechanical properties of silk, the performance of butterfly silk was found to be weaker than that of silkworm silk. Therefore, the P. polytes silk girdle adopts the strategy of merging a dozen silk threads to improve its strength and toughness, thereby making it difficult to break. In addition, we explained how the protein sequence and structure of butterfly silk impact its performance. In conclusion, we discovered that butterfly pupae develop unique body features to establish secure bonds with silk. This enables them to effectively undergo metamorphosis and endure harsh weather conditions and surroundings.
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Borboletas , Pupa , Seda , Animais , Borboletas/fisiologia , Seda/química , Árvores , BombyxRESUMO
Effective dewatering is vital for both sludge treatment and resource recovery. This study focuses on converting post-anaerobic digested sludge into biochar to enhance sludge dewatering. The sludge-derived biochar is further modified with polyacrylamide (PAM-ADBC) and applied with sulfuric acid-modified montmorillonite (HMTS) for better performance. Significant advancements in dewatering were noted, even at reduced HMTS (0.1 g/g DS) and PAM-ADBC (25 g/kg DS) dosages. These improvements resulted in a remarkable 41.96% enhancement in capillary suction time (17.2 s) and a notable 20.26% reduction in moisture content (66.33%), respectively, all while maintaining a stable pH level. HMTS, with leached cations, improved dewatering by decomposing the extracellular polymeric substance structure through electro-neutralization to release the internal bound water within sludge flocs. Simultaneously, PAM-ADBC coagulated decomposed sludge particles into larger flocs to form a skeletal structure with itself to discharge internal water in compression dewatering. This study introduces a resource recovery method for anaerobically digested sludge and highlights its potential for sustainable utilization.
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Resinas Acrílicas , Bentonita , Carvão Vegetal , Esgotos , Eliminação de Resíduos Líquidos , Esgotos/química , Carvão Vegetal/química , Anaerobiose , Eliminação de Resíduos Líquidos/métodos , Bentonita/química , Resinas Acrílicas/química , Ácidos Sulfúricos/químicaRESUMO
Unforeseen failures in girth welds present a significant challenge for the pipeline industry. This study utilizes 3D Digital Image Correlation (DIC) assisted cross-weld tensile testing to analyze the strain response of high-strength thick-walled pipelines, providing essential insights into the strain migration and fracture mechanisms specific to girth welds. The results reveal that the welding process significantly affects the mechanical distribution within the girth weld. The tested Shielded Metal Arc Welded (SMAW-ed) pipe exhibited undermatched girth welds due to high heat input, while Gas Metal Arc Welding (GMAW) introduced a narrower weld and Heat-Affected Zone (HAZ) with higher hardness than the base metal, indicative of overmatched girth welds. Strain migration, resulting from a combination of metallurgical heterogeneous materials and geometrical reinforcement strengthening, progressed from the softer HAZ to the base metal in the SMAW-ed sample with reinforcement, ultimately leading to fracture in the base metal. In contrast, the GMAW-ed sample shows no strain migration. Reinforcement significantly improves the tensile strength of girth welds and effectively prevents failure in the weld region. Sufficient reinforcement is crucial for minimizing the risk of failure in critical areas such as the weld metal and HAZ, particularly in SMAW-ed pipes.
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BACKGROUND: Postoperative central diabetes insipidus (CDI) is commonly observed in craniopharyngioma (CP) patients, and the inflammatory response plays an important role in CPs. We aimed to evaluate the predictive value of preoperative peripheral inflammatory markers and their combinations regarding CDI occurrence in CPs. METHODS: The clinical data including preoperative peripheral inflammatory markers of 208 CP patients who underwent surgical treatment were retrospectively collected and analyzed. The preoperative peripheral white blood cells (WBC), neutrophils, lymphocytes, monocytes, platelet (PLT), neutrophil-to-lymphocyte ratio (NLR), derived-NLR (dNLR), monocyte-to-lymphocyte ratio (MLR) and PLT-to-lymphocyte ratio (PLR) were assessed in total 208 CP patients and different age and surgical approach CP patient subgroups. Their predictive values were evaluated by the receiver operator characteristic curve analysis. RESULTS: Preoperative peripheral WBC, neutrophils, NLR, dNLR, MLR, and PLR were positively correlated and lymphocyte was negatively associated with postoperative CDI occurrence in CP patients, especially when WBC ≥ 6.66 × 109/L or lymphocyte ≤ 1.86 × 109/L. Meanwhile, multiple logistic regression analysis showed that WBC > 6.39 × 109/L in the > 18 yrs age patients, WBC > 6.88 × 109/L or lymphocytes ≤ 1.85 × 109/L in the transcranial approach patients were closely associated with the elevated incidence of postoperative CDI. Furthermore, the area under the curve obtained from the receiver operator characteristic curve analysis showed that the best predictors of inflammatory markers were the NLR in total CP patients, the MLR in the ≤ 18 yrs age group and the transsphenoidal group, the NLR in the > 18 yrs age group and the dNLR in the transcranial group. Notably, the combination index NLR + dNLR demonstrated the most valuable predictor in all groups. CONCLUSIONS: Preoperative peripheral inflammatory markers, especially WBC, lymphocytes and NLR + dNLR, are promising predictors of postoperative CDI in CPs.
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Craniofaringioma , Diabetes Insípido Neurogênico , Neoplasias Hipofisárias , Complicações Pós-Operatórias , Humanos , Craniofaringioma/cirurgia , Craniofaringioma/sangue , Craniofaringioma/complicações , Feminino , Masculino , Estudos Retrospectivos , Adulto , Neoplasias Hipofisárias/cirurgia , Neoplasias Hipofisárias/sangue , Neoplasias Hipofisárias/complicações , Complicações Pós-Operatórias/sangue , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/diagnóstico , Adolescente , Pessoa de Meia-Idade , Criança , Adulto Jovem , Diabetes Insípido Neurogênico/sangue , Diabetes Insípido Neurogênico/etiologia , Neutrófilos , Biomarcadores/sangue , Linfócitos , Inflamação/sangue , Contagem de Leucócitos , Período Pré-Operatório , Pré-Escolar , Prognóstico , Curva ROCRESUMO
The fruit of Choerospondias axillaris (Anacardiaceae), known as south wild jujube in China, has been consumed widely in several regions of the world to produce fruit pastille and leathers, juice, jam, and candy. A comprehensive chemical study on the fresh fruits led to the isolation and identification of 18 compounds, including 7 new (1-7) and 11 known (8-18) comprised of 5 alkenyl (cyclohexenols and cyclohexenones) derivatives (1-5), 3 benzofuran derivatives (6-8), 6 flavonoids (9-14) and 4 lignans (15-18). Their structures were elucidated by extensive spectroscopic analysis. The known lignans 15-18 were isolated from the genus Choerospondias for the first time. Most of the isolates exhibited significant inhibitory activity on α-glucosidase with IC50 values from 2.26 ± 0.06 to 43.9 ± 0.96 µM. Molecular docking experiments strongly supported the potent α-glucosidase inhibitory activity. The results indicated that C. axillaris fruits could be an excellent source of functional foods that acquire potential hypoglycemic bioactive components.
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Quantitative analysis of Rumex nepalensis var. remotiflorus revealed that its roots contain rich anthraquinones, which has emodin, chrysophanol, and physcion contents of up to 0.30, 0.67, and 0.98 mg/g, respectively. Further phytochemical study led to the isolation and purification of seven undescribed phenolic constituents, including one flavan derivative with a 13-membered ring, polygorumin A (1), two dianthrone glucosides, polygonumnolides F and G (2, 3), two diphenylmethanones, rumepalens A and B (4, 5), and a pair of epimeric oxanthrone C-glucosides, rumejaposides K and L (6a, 6b) from the roots of R. nepalensis var. remotiflorus. Furthermore, 1 undescribed natural product, 1-ß-D-glucoside-6'-[(2E)-3-(4-hydroxy-3-methoxyphenyl)-2-propenoate]-3-hydroxy-5-methylphenyl (19), and 21 known phenolic compounds were obtained from the aforementioned plant for the first time. Their structures were elucidated through extensive spectroscopic data analysis. Notably, compounds 1, 4-5, and 7-9 exhibited inhibitory activity on α-glucosidase with IC50 values ranging from 1.61 ± 0.17 to 32.41 ± 0.87 µM. In addition, the isolated dianthrone, chrysophanol bianthrone (14), showed obvious cytotoxicity against four human cancer cell lines (HL-60, SMMC-7721, A-549, and MDA-MB-231) with IC50 values ranging from 3.81 ± 0.17 to 35.15 ± 2.24 µM. In silico target prediction and molecular docking studies demonstrated that the mechanism of the anticancer activity of 14 may be related to the interaction with protein kinase CK2.
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Antineoplásicos Fitogênicos , Inibidores de Glicosídeo Hidrolases , Fenóis , Rumex , alfa-Glucosidases , Humanos , Fenóis/farmacologia , Fenóis/química , Fenóis/isolamento & purificação , Inibidores de Glicosídeo Hidrolases/farmacologia , Inibidores de Glicosídeo Hidrolases/química , Inibidores de Glicosídeo Hidrolases/isolamento & purificação , Rumex/química , alfa-Glucosidases/metabolismo , alfa-Glucosidases/efeitos dos fármacos , Antineoplásicos Fitogênicos/farmacologia , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Estrutura Molecular , Ensaios de Seleção de Medicamentos Antitumorais , Simulação de Acoplamento Molecular , Relação Estrutura-Atividade , Linhagem Celular Tumoral , Raízes de Plantas/química , Relação Dose-Resposta a Droga , Proliferação de Células/efeitos dos fármacosRESUMO
Hearing preservation (HP) during vestibular schwannomas (VSs) surgery poses a significant challenge. Although brainstem auditory evoked potentials (BAEPs) on the affected side are commonly employed to monitor cochlear nerve function, their low signal-to-noise ratio (SNR) renders them susceptible to interferences, compromising their reliability. We retrospectively analyzed the data of patients who underwent tumor resection, while binaural brainstem auditory evoked potentials (BAEPs) were simultaneously recorded during surgery. To standardize BAEPs on the affected side, we incorporated the synchronous healthy side as a reference (interval between affected and healthy side ≤ 3 min). A total of 127 patients were enrolled. Comparison of the raw BAEPs data pre- and post-tumor resection revealed that neither V-wave amplitude (Am-V) nor latency (La-V) could serve as reliable predictors of HP simultaneously. However, following standardization, V-wave latency (STIAS-La-V) and amplitude (STIAS-Am-V) emerged as stable predictors of HP. Furthermore, the intraoperative difference in V-wave amplitude (D-Am-V) predicted postoperative HP in patients with preoperative HP and remained predictive after standardization. The utilization of intraoperative synchronous healthy side BAEPs as a reference to eliminate interferences proves to be an effective approach in enhancing the reliability of BAEPs for predicting HP in VSs patients.
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Potenciais Evocados Auditivos do Tronco Encefálico , Neuroma Acústico , Humanos , Neuroma Acústico/cirurgia , Neuroma Acústico/fisiopatologia , Feminino , Potenciais Evocados Auditivos do Tronco Encefálico/fisiologia , Masculino , Pessoa de Meia-Idade , Adulto , Estudos Retrospectivos , Idoso , Audição , Adulto JovemRESUMO
The utilization of agroindustrial wastes to enrich food protein resources and the exploration of their broader applications are crucial for addressing the food crisis and achieving sustainable development goals. In this study, reeling wastewater-derived sericin was hydrolyzed using papain and trypsin to prepare sericin peptide (SRP) and was used as an antihardening ingredient of high-protein nutrition bars (HPNBs). The mechanism of the antihardening effect of SRP was elucidated by investigating the content of advanced glycation end products and protein oxidation products (carbonyl and free sulfhydryl), and the molecular weight change of HPNBs during storage before and after the addition of SRP. Our results confirmed the fortification of HPNBs with SRP, which is beneficial for the promotion and expansion of sericin applications in the food industry, with positive implications for the rational utilization of protein resources and the enrichment of food protein sources.
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Peptídeos , Sericinas , Águas Residuárias , Sericinas/química , Águas Residuárias/química , Peptídeos/química , Armazenamento de Alimentos , Proteínas Alimentares/metabolismo , Proteínas Alimentares/químicaRESUMO
Cellular therapy holds immense promise to remuscularize the damaged myocardium but is practically hindered by limited allogeneic sources of cardiac-committed cells that engraft stably in the recipient heart after transplantation. Here, we demonstrate that the pericardial tissue harbors myogenic stem cells (pSCs) that are activated in response to inflammatory signaling after myocardial infarction (MI). The pSCs derived from the MI rats (MI-pSCs) show in vivo and in vitro cardiac commitment characterized by cardiac-specific Tnnt2 expression and formation of rhythmic contraction in culture. Bulk RNA-seq analysis reveals significant upregulation of a panel of genes related to cardiac/myogenic differentiation, paracrine factors, and extracellular matrix in the activated pSCs compared to the control pSCs (Sham-pSCs). Notably, we define MyoD as a key factor that governs the process of cardiac commitment, as siRNA-mediated MyoD gene silencing results in a significant reduction of myogenic potential. Injection of the cardiac-committed cells into the infarcted rat heart leads to long-term survival and stable engraftment in the recipient myocardium. Therefore, these findings point to pericardial myogenic progenitors as an attractive candidate for cardiac cell-based therapy to remuscularize the damaged myocardium.
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Chromium (VI) in soil poses a significant threat to the environment and human health. Despite efforts to remediate Cr contaminated soil (Cr-soil), instances of re-yellowing have been observed over time. To understand the causes of re-yellowing as well as the influence of overdosed chemical reductant in remediating Cr-soil, experiments on excess reducing agent interference and soil re-yellowing mechanisms under different extreme conditions were conducted. The results show that the USEPA method 3060A & 7196A combined with K2S2O8 oxidation is an effective approach to eliminate interference from excess FeSO4 reducing agents. The main causes of re-yellowing include the failure of reducing agents, disruption of soil lattice, and interactions between manganese oxides and microorganisms. Under various extreme conditions simulated across the four seasons, high temperature and drought significantly accelerated the failure of reducing agents, resulting in the poorest remediation effectiveness for Cr-soil (91.75 %). Dry-wet cycles promoted the formation of soil aggregates, negatively affecting Cr(VI) removal. While these extreme conditions caused relatively mild re-yellowing (9.46 %-16.79 %) due to minimal soil lattice damage, the potential risk of re-yellowing increases with the failure of reducing agents and the release of Cr(VI) within the lattice. Prolonged exposure to acid rain leaching and freeze-thaw cycles disrupted soil structure, leading to substantial leaching and reduction of insoluble Cr, resulting in optimal remediation effectiveness (94.37 %-97.73 %). As reducing agents gradually and the involvement of the water medium, significant re-yellowing occurred in the remediated soil (51.52 %). Mn(II) in soil enriched relevant microorganisms, and the Mn(IV)-mediated biological oxidation process was also one of the reasons for soil re-yellowing.
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Although being viewed as a promising technology for reclamation of carbon and phosphorus from excess sludge, anaerobic fermentation (AF) grapples with issues such as a low yield of volatile fatty acids (VFAs) and high phosphorus recovery costs. In this study, we synthesized Fe3O4@MOF-808 (FeM) with abundant defects and employed it to simultaneously enhance VFAs and phosphorus recovery during sludge anaerobic fermentation. Through pre-oxidization of sludge catalyzed by FeM-induced peroxydisulfate, the soluble organic matter increased by 2.54 times, thus providing ample substrate for VFAs production. Subsequent AF revealed a remarkable 732.73 % increase in VFAs and a 1592.95 % increase in phosphate. Factors contributing to the high VFAs yield include the non-biological catalysis of unsaturated Zr active sites in defective FeM, enhancing protein hydrolysis, and the inhibition of methanogenesis due to electron competition arising from the transformation between Fe(III) and Fe(II) under Zr influence. Remarkably, FeM exhibited an adsorption capacity of up to 92.64 % for dissolved phosphate through ligand exchange and electrostatic attractions. Furthermore, FeM demonstrated magnetic separation capability from the fermentation broth, coupled with excellent stability and reusability in both catalysis and adsorption processes.
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Fósforo , Esgotos , Fermentação , Esgotos/química , Anaerobiose , Carbono , Compostos Férricos , Ácidos Graxos Voláteis/metabolismo , Fosfatos , Concentração de Íons de HidrogênioRESUMO
The complexity and high cost to separate and recover short chain fatty acids (SCFAs), ammonium ions, and phosphates in the sludge fermentation liquid hinder the application of sludge anaerobic fermentation. In this study, an interesting phenomenon was found in a sludge anaerobic fermenter with a dynamic membrane (DM) which could not only enhance SCFAs production but also retain most SCFAs in fermenter. The separation factor of DM for NH3-N/SCFAs and PO43-/SCFAs throughout the DM development were about 40 and 80, respectively. Analysis reveals that rejection of SCFAs by DM could not be simply correlated to molecular weight or membrane pore size. The rejection mechanisms might be dominated by Donnan rejection. In addition, biodegradation in the DM may also have contribution. Findings of this study suggest the potential of DM as an economical technology for nutrients and SCFAs recover.