Different advanced oxidation processes (AOPs) were applied to the treatment of a real cotton-textile dyeing wastewater as a pre-oxidation step to enhance the biodegradability of the recalcitrant ...compounds, which can be further oxidized using a biological process. Tests were conducted on a lab-scale prototype using artificial solar radiation and at pilot scale with compound parabolic collectors using natural solar radiation. The cotton-textile dyeing wastewater presents a lilac color, with a maximum absorbance peak at 641 nm, alkaline pH (pH = 8.2), moderate organic content (DOC = 152 mg C L⁻¹, COD = 684 mg O₂ L⁻¹) and low-moderate biodegradability (40 % after 28 days in Zahn–Wellens test). All the tested processes contributed to an effective decolorization and mineralization, but the most efficient process was the solar-photo-Fenton with an optimum catalyst concentration of 60 mg Fe²⁺ L⁻¹, leading to 98.5 % decolorization and 85.5 % mineralization after less than 0.1 and 5.8 kJUV L⁻¹, respectively. In order to achieve a final wastewater with a COD below 250 mg O₂ L⁻¹ (discharge limit into water bodies imposed by the Portuguese Legislation-Portaria no. 423/97 of 25 June 1997), considering the combination of a solar-photo-Fenton reaction with a biological process, the phototreatment energy required is 0.5 kJUV L⁻¹, consuming 7.5 mM hydrogen peroxide, resulting in 58.4 % of mineralization Formula: see text
We investigated the pH-dependent properties of multilayered films made of chitosan (CHI) and alginate (ALG) and focused on their postassembly response to different pH environments using a quartz ...crystal microbalance with dissipation monitoring (QCM-D), swelling studies, ζ potential measurements, and dynamic mechanical analysis (DMA). In an acidic environment, the multilayers presented lower dissipation values and, consequently, higher moduli when compared with the values obtained for the pH used during the assembly (5.5). When the multilayers were exposed to alkaline environments, the opposite behavior occurred. These results were further corroborated by the ability of this multilayered system to exhibit a reversible swelling–deswelling behavior within the pH range from 3 to 9. The changes in the physicochemical properties of the multilayer system were gradual and different from those of individual solubilized polyelectrolytes. This behavior is related to electrostatic interactions between the ionizable groups combined with hydrogen bonding and hydrophobic interactions. Beyond the pH range of 3–9, the multilayers were stabilized by genipin cross-linking. The multilayered films also became more rigid while the pH responsiveness conferred by the ionizable moieties of the polyelectrolytes was preserved. This work demonstrates the versatility and feasibility of LbL methodology to generate inherently pH stimulus-responsive nanostructured films. Surface functionalization using pH responsiveness endows several biomedical applications with abilities such as drug delivery, diagnostics, microfluidics, biosensing, and biomimetic implantable membranes.
This study focuses on the degradation of pharmaceuticals from a municipal wastewater after secondary treatment by applying various advanced oxidation processes (AOPs) and electrochemical AOPs (EAOPs) ...like UVC, H2O2/UVC, anodic oxidation (AO), AO with electrogenerated H2O2 (AO-H2O2), AO-H2O2/UVC and photoelectro-Fenton (PEF) using either UVC radiation (PEF-UVC) or UVA radiation (PEF-UVA). The municipal wastewater after secondary treatment was spiked with 5.0 mg L−1 of trimethoprim (TMP) antibiotic. The efficiency of processes to remove TMP followed the order UVC < AO-H2O2 < PEF-UVA << AO ≈ PEF-UVC < AO-H2O2/UVC < PEF-UVA (pH = 2.8) < H2O2/UVC ≈ PEF-UVC (pH = 2.8), using neutral pH, except when identified. While the UVC radiation alone led to a very low TMP removal, the H2O2/UVC process promoted a very high TMP degradation due to the production of hydroxyl radicals (OH) by H2O2 cleavage. In the AO-H2O2/UVC process, the electrogeneration of H2O2 can avoid the risks associated with the transportation, storage and manipulation of this oxidant and, furthermore, OH at the anode surface are also formed. Nevertheless, low contents of H2O2 were detected mainly at the beginning of the reaction, leading to a lower initial reaction rate when compared with the H2O2/UVC system. In the PEF-UVC, the addition of iron at neutral pH led to the visible formation of insoluble iron oxides that can filter the light. At pH 2.8, the iron remained dissolved, thereby promoting the Fenton's reaction and increasing the organics removal. The UVA-driven processes showed limited efficiency when compared with those using UVC light. For all processes with H2O2 electrogeneration, the active chlorine species can be scavenged by the H2O2, diminishing the efficiency of the processes. This can explain the lower efficiency of AO-H2O2 when compared with AO. Moreover, the degradation of the MWWTP effluent spiked with 18 pharmaceuticals in μg L−1 during AO process was assessed as well as the influence of the following operational variables on the process efficiency: (i) H2O2 concentration on H2O2/UVC, (ii) current density on AO, AO-H2O2, AO-H2O2/UVC, PEF-UVC and PEF-UVA, and (iii) pH on PEF-UVA.
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•First study on AO-H2O2, AO-H2O2/UVC, PEF-UVC and PEF-UVA to degrade a MWWTP effluent.•Unprecedented comparison of chemical and electrochemical advanced oxidation processes.•Trimethoprim removal: PEF-UVC ≈ H2O2/UVC > PEF-UVA > AO-H2O2/UVC > AO > AO-H2O2 > UVC.•Assessment of pharmaceuticals removal at mg L−1 and μg L−1 levels.•Assessment of the effect of H2O2 content, current density and pH on various processes.
A solar photo-Fenton process combined with a biological nitrification and denitrification system is proposed for the decontamination of a landfill leachate in a pilot plant using photocatalytic ...(4.16 m
2 of Compound Parabolic Collectors – CPCs) and biological systems (immobilized biomass reactor). The optimum iron concentration for the photo-Fenton reaction of the leachate is 60 mg Fe
2+ L
−1. The organic carbon degradation follows a first-order reaction kinetics (
k = 0.020 L kJ
UV
−1,
r
0 = 12.5 mg kJ
UV
−1) with a H
2O
2 consumption rate of 3.0 mmol H
2O
2 kJ
UV
−1. Complete removal of ammonium, nitrates and nitrites of the photo-pre-treated leachate was achieved by biological denitrification and nitrification, after previous neutralization/sedimentation of iron sludge (40 mL of iron sludge per liter of photo-treated leachate after 3 h of sedimentation). The optimum C/N ratio obtained for the denitrification reaction was 2.8 mg CH
3OH per mg N–NO
3
−, consuming 7.9 g/8.2 mL of commercial methanol per liter of leachate. The maximum nitrification rate obtained was 68 mg N–NH
4
+ per day, consuming 33 mmol (1.3 g) of NaOH per liter during nitrification and 27.5 mmol of H
2SO
4 per liter during denitrification. The optimal phototreatment energy estimated to reach a biodegradable effluent, considering Zahn–Wellens, respirometry and biological oxidation tests, at pilot plant scale, is 29.2 kJ
UV L
−1 (3.3 h of photo-Fenton at a constant solar UV power of 30 W m
−2), consuming 90 mM of H
2O
2 when used in excess, which means almost 57% mineralization of the leachate, 57% reduction of polyphenols concentration and 86% reduction of aromatic content.
► The solar photo-Fenton process was found to be very efficient in the treatment of leachates, enhancing the biodegradability of the leachate and making possible a subsequent treatment by a biological oxidation process. ► Solar energy is an important natural resource and using it in advanced oxidation processes is probably one of the best ways to make the detoxification of leachates from sanitary landfills economically attractive. ► Biological nitrogen removal was achieved by a by two-step process: aerobic nitrification of ammonia to nitrite and then to nitrate followed by anoxic denitrification of nitrate to nitrite, nitric oxide, nitrous oxide and nitrogen gas using an external carbon source.
Membranes made of chitosan (CHT) and chondroitin sulfate (CS) are herein presented using a polyelectrolyte complexation sedimentation/evaporation method. The membranes present high roughness and ...heterogeneous morphology induced by salt crystals. Exposing the membranes to different salt concentrations induces saloplastic behavior, as shown by an increasing water absorption and decreasing stiffness while exposed to increasing concentrations of salt. Establishing contact between two parts of a cut membrane leads to their self-adhesion and maintenance of their stretching ability. The membranes sustain the adhesion of ATDC5 prechondrocyte cells, inducing their rearrangement in cellular aggregates typical of chondrogenesis, and the expression of cartilage markers. Impregnated TGF-β3 remains loaded after 14 days of incubation, releasing only 1.2% of its total loaded mass. CHT/CS polyelectrolyte membranes are here shown as suitable candidates for the biomedical field, namely, for cartilage regeneration.
Cork powder and granules are the major subproducts of the cork industry, one of the leading economic activities in Portugal and other Mediterranean countries. Many applications have been envisaged ...for this product, from cork stoppers passing through the incorporation in agglomerates and briquettes to the use as an adsorbent in the treatment of gaseous emissions, waters and wastewaters. This paper aims at reviewing the state of the art on the properties of cork and cork powder and their application in adsorption technologies. Cork biomass has been used on its original form as biosorbent for heavy metals and oils, and is also a precursor of activated carbons for the removal of emerging organic pollutants in water and VOCs in the gas phase. Through this literature review, different potential lines of research not yet explored can be more easily identified.
► Outline of cork powder and granules' chemical and physical properties. ► Overview of the application of cork powder and granules in biosorption. ► Review of previously reported methods for activated carbon preparation from cork. ► Summary of the main applications of cork-based activated carbons in adsorption.
Background
Neuropsychiatric symptoms (NPS) have been shown to affect the progression and development of Alzheimer’s disease (AD) in the elderly. However, the published data are still controversial ...and limited in large cohort-based NPS study.
Aim
To explore the potential relationship between NPS and mild cognitive impairment (MCI) among the elderly of Chinese community.
Methods
A total of 465 Chinese community-dwelling elderly (age ≥ 60 years) with mild cognitive impairment (MCI) were recruited into this investigation. At baseline, enrolled participants were assessed for Clinical Dementia Rating (CDR), mini-psychiatric examination. They were also subjected to categorical language fluency test, list learning and delayed recall. We assessed the NPS severity by Neuropsychological Inventory (NPI). The global cognitive status (GCS) of the participants at the end of the 3-year study period were measured with the CDR.
Results
Approximately 41.6% of subjects had 1 or more NPS (total NPI score ≥ 1) at baseline. The most common NPSs were nocturnal behavior (20.8%), depression (17.3%), apathy (12.7%) and anxiety (13.2%). At the end of 3-year follow-up, 26.9% of baseline depressed patients developed AD, while 15.2% of baseline non-depressed patients developed AD (χ2 = 4.86, P=0. 04). Abnormal motor behavior was significantly correlated with cognitive deterioration as well (χ2 = 5.75, P=0. 03). Logistic regression analysis revealed that depression was considered as a risk factor for AD progression at baseline (95% CI: 1.12-5.67, OR=2.37, P=0.03).
Conclusions
Depression may be an independent factor representing early neurodegeneration in elder patients with MCI. Further studies are warranted to assess whether effective management of NPS promotes the cognitive functions.
The lack of knowledge on the degradation of layer-by-layer structures is one of the causes hindering its translation to preclinical assays. The enzymatic degradation of chitosan/hyaluronic acid films ...in the form of ultrathin films, freestanding membranes, and microcapsules was studied resorting to hyaluronidase. The reduction of the thickness of ultrathin films was dependent on the hyaluronidase concentration, leading to thickness and topography variations. Freestanding membranes exhibited accelerated weight loss up to 120 h in the presence of the enzyme, achieving complete degradation. Microcapsules with around 5 μm loaded simultaneously with FITC-BSA and hyaluronidase showed that the coencapsulation of such enzyme and protein mixture led to a FITC-BSA release four times higher than in the absence of hyaluronidase. The results suggest that the degradation of LbL devices may be tuned via embedded enzymes, namely, in the controlled release of active agents in biomedical applications.
Biosorption is an emerging technique for water treatment utilizing abundantly available biomaterials (especially agricultural wastes). Among several agricultural wastes studied as biosorbents for ...water treatment, coconut has been of great importance as various parts of this tree (e.g. coir, shell, etc.) have been extensively studied as biosorbents for the removal of diverse type of pollutants from water. Coconut-based agricultural wastes have gained wide attention as effective biosorbents due to low-cost and significant adsorption potential for the removal of various aquatic pollutants. In this review, an extensive list of coconut-based biosorbents from vast literature has been compiled and their adsorption capacities for various aquatic pollutants as available in the literature are presented. Available abundantly, high biosorption capacity, cost-effectiveness and renewability are the important factors making these materials as economical alternatives for water treatment and waste remediation. This paper presents a state of the art review of coconut-based biosorbents used for water pollution control, highlighting and discussing key advancement on the preparation of novel adsorbents utilizing coconut wastes, its major challenges together with the future prospective. It is evident from the literature survey that coconut-based biosorbents have shown good potential for the removal of various aquatic pollutants. However, still there is a need to find out the practical utility of such developed adsorbents on commercial scale, leading to the superior improvement of pollution control and environmental preservation.
The identification of transcriptional enhancers in the human genome is a prime goal in biology. Enhancers are typically predicted via chromatin marks, yet their function is primarily assessed with ...plasmid-based reporter assays. Here, we show that such assays are rendered unreliable by two previously reported phenomena relating to plasmid transfection into human cells: (i) the bacterial plasmid origin of replication (ORI) functions as a conflicting core promoter and (ii) a type I interferon (IFN-I) response is activated. These cause confounding false positives and negatives in luciferase assays and STARR-seq screens. We overcome both problems by employing the ORI as core promoter and by inhibiting two IFN-I-inducing kinases, enabling genome-wide STARR-seq screens in human cells. In HeLa-S3 cells, we uncover strong enhancers, IFN-I-induced enhancers, and enhancers endogenously silenced at the chromatin level. Our findings apply to all episomal enhancer activity assays in mammalian cells and are key to the characterization of human enhancers.
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