Improvement Of Biodegradability Research Articles

Sequential treatment for stabilized landfill leachate by ozonation–adsorption and adsorption–ozonation methods

This paper investigates the potential use of sequential treatment using ozonation–adsorption and adsorption–ozonation processes for stabilized landfill leachate treatment. Zeolite was used as adsorbent due to its novel composition of naturally hydrated aluminosilicate minerals. Preliminary tests were conducted to determine the optimum conditions of ozone and zeolite. Results demonstrated that the usage of ozonation as a post-treatment for adsorption could effectively remove 92%, 82%, and 75% of colour, COD, and NH4–N, respectively. In addition, the application of ozonation as a pre-treatment showed a good removal for colour, COD, and NH4–N with a removal efficiency of 93%, 80%, and 71%, respectively. Also, an improvement in biodegradability of the leachate was achieved after ozonation/adsorption and adsorption/ozonation which increases the BOD5/COD ratio from 0.016 to 0.195 and 0.194, respectively, where the maximum BOD5/COD in the raw leachate was 0.02. This is attributed to the oxidation of high molecular weight organics in the sample. A combined treatment leads to a removal of inorganic and small non-biodegradable organic molecules, which decreases the COD and further improve the BOD5/COD ratio. This study demonstrates that the application of ozonation as a pre- and post-treatment with zeolite is an effective treatment method that can improve the treatment of stabilized landfill leachate .

Nickel foam as a new material for chlortetracycline electrochemical oxidation: Biodegradability improvement and biological treatment

Chlortetracycline CTC is an organochlorine compound released from industrial pharmaceutical waste. This pollutant had dangerous effects in aquatic organisms and human health, since it is responsible for inhibition of microbial activity and growth. In this study, the elimination of CTC from water is targeted. Biodegradability, based on the BOD5/COD ratio was studied, showing the non-feasibility of a direct biological treatment. Cyclic voltammetry analysis on a nickel electrode revealed a significant electrochemical activity of CTC. An electrochemical pre-treatment was therefore carried out in a percolation cell using a nickel foam as a working electrode at the potential of 0.5 V/SCE. The operating parameters were optimized. A degradation yield of 99% was achieved for an initial concentration of pollutant of 50 mg L−1 and a flow rate of 5 mL min−1 in alkaline conditions. After electrolysis, a total dechlorination of CTC was observed. The biodegradability ratio was improved, from 0.13 to 0.33 after electrolysis; while the dissolved organic carbon (DOC) analysis revealed that the level of mineralization remained low 27%. A 21 days biological treatment with activated sludge was then carried out, leading to an overall mineralization yield of 78%.

Development of Euphorbia Latex and Bamboo Fiber Based Green Composite.

Novel composites with improved mechanical strength, thermally stability and better biodegradability were fabricated using polyester resin (PR) and euphorbia coagulum (EC) with natural bamboo fiber (BF) by a compression molding technique. The addition of EC makes the composite more pronounced for alkali-treated BF. The composites were characterized in terms of water absorption, mechanical, thermal and biodegradability. Composites showed considerable improvement in thermal stability, mechanical properties (flexural strength and impact strength) and biodegradability. EC modified composite shows maximum improvement in physico-mechanical properties compared to other composites. The inoculation of EC modified and unmodified composite with fungi resulted in higher growth on modified composite compared to unmodified composite. These novel composites could be labeled as sustainable material because they were prepared from low-cost BF and EC through a green approach. The composite material developed can be used in building constructions as wood substitution, automotive parts, sports goods, etc.

Enhanced Biodegradation/Photodegradation of Organophosphorus Fire Retardant Using an Integrated Method of Modified Pharmacophore Model with Molecular Dynamics and Polarizable Continuum Model.

A comprehensive 3D-quantitative structure–activity relationship (QSAR) pharmacophore model was constructed using the values of comprehensive biodegradation/photodegradation effects of 17 organophosphorus flame retardants (OPFRs) evaluated by a normalization method to modify OPFRs with high biodegradation/photodegradation, taking tris(chloro-isopropyl) phosphate (TCPP), tris(2-chloroethyl) phosphate (TCEP) and tris(1-chloro-2-propyl) phosphate (TCIPP)—which occur frequently in the environment, and are the most difficult to degrade as target molecules. OPFR-derivative molecules TCPP–OH shows the highest improvement in biodegradation and photodegradation (55.48% and 46.37%, respectively). On simulating the biodegradation path and photodegradation path, it is found that the energy barrier of TCPP–OH for phosphate bond cleavage is reduced by 15.73% and 52.52% compared to TCPP after modification, respectively. Finally, in order to further significantly improve its biodegradability and photodegradation, the efficiency enhancement in the biodegradation and photodegradation of TCPP–OH are analyzed under the simulated environment by molecular dynamics and polarizable continuum model, respectively. The results of molecular dynamics show that the biodegradation efficiency of the TCPP–OH increased by 75.52% compared to TCPP. The UV spectral transition energy (4.07 eV) of TCPP–OH under the influence of hydrogen peroxide solvation effect is 44.23% lower than the actual transition energy (7.29 eV) of TCPP.

TRENDS IN THE PROCESS OF GREENING LUBRICANTS

In this article, the authors have characterized the main activities that reduce the impact of lubricants on the environment. To begin with, new solutions in the area of engine oils that reduce the emission of harmful substances in exhaust gases (“Low SAPS” oils) were discussed. Next, the activities concerning the improvement of biodegradability of lubricating oils used in devices in Nature Reserves, as well as in all of the “open lubrication systems” were characterized. Another problem was related to the non-toxicity (and other derivative features) of lubricants that may have incidental contact with a sensitive technological medium in production processes (in the food, pharmaceutical, and cosmetics industries). The last issue that was discussed concerns the compatibility of compressor oils with refrigerants in connection with the global exchange program of Freon for more environmentally friendly substances (currently, mainly affecting global warming to a lesser extent).

Development of a treatment train for the remediation of a hazardous industrial waste landfill leachate: A big challenge

This study focuses on the development of a treatment train for a leachate from a hazardous industrial waste landfill (HIWL) previously treated by: (i) catalytic oxidation with hydrogen peroxide (H2O2) for sulphide and sulphite conversion into oxidized sulphur species, including sulphate, and (ii) chemical precipitation of sulphate as barite. The complete treatment line counted on four more stages: (iii) 1st biological oxidation for removal of biodegradable organic compounds and nitrogen species, (iv) coagulation with ferric chloride (coagulant dose of 100 mg Fe L−1, pH 2.8) for removal of a fraction of recalcitrant organics and suspended solids, (v) photo-Fenton oxidation using ultraviolet A (UVA) radiation (PF-UVA) (pH 2.8, initial total dissolved iron content of 140 mg L−1, treatment time of ~4 h) for recalcitrant organics degradation and biodegradability improvement, and (vi) 2nd biological oxidation for removal of the biodegradable organic matter resulting from the PF-UVA process. The use of anodic oxidation or photoelectro-Fenton processes in stage (v) demonstrated to be unfeasible. A chemical oxygen demand (COD) below 1000 mg O2 L−1, a common limit imposed by municipal wastewater treatment plants (MWWTPs) to effluents discharged into the municipal sewer, was achieved after a feasible treatment time (~4 h) using the multistep approach. The remediation of the HIWL leachate proved to be a big challenge.

Biodegradability improvement of clopyralid wastes through electrolysis using different diamond anodes

The use of boron-doped (BDDs) anodes for efficient removal of complex organic molecules, such as organochlorine compounds, is well stated in the literature. However, the role of the different characteristics of this anode on the transformation of these type of contaminants into more biodegradable molecules is a topic of interest that need to be clarified when aimed an efficient combination of an electrochemical system as a previous step to biological treatment. In this work, improvement in the biodegradability of synthetic wastes polluted with clopyralid, as an organochlorine model compound, is studied after electrolysis with different BDDs in the presence of the two most common supporting electrolytes (containing sulfate or chloride ions). For that, clopyralid removal, mineralization, aromatics intermediates, short-chain carboxylic acids, and inorganic ions were monitored. Improved results were found in sulfate media for BDD with 200 ppm, capable of removing 88.7% of contaminants and 85% of TOC, resulting in an improvement in biodegradability of almost 7-fold compared to the initial sample. These findings point out that lower doping levels are preferable when coupling studied technologies.

Improvement in mechanical properties and biodegradability of PLA using poly(ethylene glycol) and triacetin for antibacterial wound dressing applications.

Wound is among the most common injuries. A suitable wound dressing has a significant effect on the healing process. In this study, a porous wound dressing was prepared using poly (lactic acid) (PLA) and two plasticizers, polyethylene glycol (PEG) and triacetin (TA), through solvent casting method. For antibacterial activities, metronidazole was incorporated in the structure. The morphology was investigated by scanning electron microscopy (SEM). In addition, the effect of plasticizers ratio on porosity growth was evaluated. It was also observed that each had a unique effect on the structure's porosity. The mechanical properties confirmed the effect of both plasticizers on increasing polymer softness and flexibility, and the most similar formulations to human skin in terms of mechanical properties were introduced. According to the results, TA had stronger effect on mechanical properties. The differential scanning calorimetry (DSC) showed the effect of increasing plasticizer concentration on crystalline structure and Tm reduction of PLA. The water contact angle measurement showed that both plasticizers enhanced hydrophilic characteristics of PLA, and this effect was weaker in PEG-containing formulations. The in vitro degradation study showed biodegradability, as a desirable property in wound dressing. Results suggested that higher degradation can be obtained by both plasticizers at the same time. The results also showed that PEG was more effective in enhancing water absorbency. In vitro drug release study indicated an explosive release and the highest amount was 85% over 186h. The antibacterial activity test confirmed the effectiveness of the drug in preventing bacterial growth in the drug-containing formulations, while it showed the antibacterial property of TA. MTT assay was performed and the cellular toxicity of the formulations was checked and those that revealed the least toxicity were introduced.

Degradation and biodegradability improvement of the landfill leachate using electrocoagulation with iron and aluminum electrodes: A comparative study

Abstract This present study investigates the comparative study of iron and aluminum electrodes for the treatment of landfill leachate by the Batch Electrocoagulation (EC) technique. The performance of EC was used to determine the removal efficiency of COD and Color. The effects of operating conditions such as electrode material, stirring speed, inter-electrode distance, electrolysis time, initial pH, and applied voltage were studied to evaluate the performance of the electrode. The electrodes were arranged in a monopolar mode by applying different cell voltages of 4, 6, 8, 10 and 12 V for 180 min of electrolysis time (ET) with a varying inter-electrode distance between 1 and 4 cm. The iron and aluminum electrodes can be successfully used as anodes and cathodes for the treatment process, which makes the process more efficient and easier to maintain. Based on the obtained results, it was observed that there was an increase in BOD/COD ratio from 0.11 to 0.79. The maximum removal of COD and Color was found to be 76.5% and 67.2% respectively, accomplished with 105 min optimum electrolysis time with a pH of 9.25 using an iron electrode. In the case of the aluminum electrode, the BOD/COD ratio was increased from 0.11 to 0.66. Over 78.4% of COD and 77.0% of Color removal was obtained with 90 min optimum electrolysis duration and pH 9.3 with an optimum 10 V and an optimum inter-electrode distance of 1 cm. However, the aluminum electrode is superior to iron as a sacrificial electrode material in terms of Color and COD removal efficiency. The aluminum electrode significantly treated landfill leachate by the electrocoagulation method under optimum experimental conditions.

PASylation Enhances the Stability, Potency, and Plasma Half-Life of Interferon α-2a: A Molecular Dynamics Simulation.

In this study, the effectiveness of PASylation in enhancing the potency and plasma half-life of pharmaceutical proteins has been accredited as an alternative technique to the conventional methods such as PEGylation. Proline, alanine, and serine (PAS) chain has shown some advantages including biodegradability improvement and plasma half-life enhancement while lacking immunogenicity or toxicity. Although some experimental studies have been performed to find the mechanism behind PASylation, the detailed mechanism of PAS effects on the pharmaceutical proteins has remained obscure, especially at the molecular level. In this study, the interaction of interferon α-2a (IFN) and PAS chain is investigated using molecular dynamics simulation method. Several important parameters including secondary structure, root-mean-square distance, and solvent accessible surface area to investigate the stability, bioavailability, and bioactivity of the PASylated protein are studied. The results demonstrate that IFN conformation is not affected critically through PASylation while it results in improvement of the protein stability and bioactivity. Therefore, PASylation can be considered as a proper biological alternative technique to increase the plasma half-life of the biopharmaceutical proteins through enlarging apparent volume. The proposed simulation represents a computational approach that would provide a basis for the study of PASylated pharmaceutical proteins for different future applications.

Assessment of substrate biodegradability improvement in anaerobic Co-digestion using a chemometrics-based metabolomic approach

Anaerobic co-digestion (AcoD) can increase methane production of anaerobic digesters in plants treating wastewater sludge by improving the nutrient balance needed for the microorganisms to grow in the digesters, resulting in a faster process stabilization. Substrate mixture proportions are usually optimized in terms of biogas production, while the metabolic biodegradability of the whole mixture is neglected in this optimisation. In this aim, we developed a strategy to assess AcoD using metabolomics data. This strategy was explored in two different systems. Specifically, we investigated the co-digestion of wastewater sludge with different proportions of either grass or fish waste using untargeted High Performance Liquid Chromatography coupled to Mass Spectrometry (HPLC-MS) metabolomics and chemometrics methods. The analysis of these data revealed that adding grass waste did not improve the metabolic biodegradability of wastewater sludge. Conversely, a synergistic effect in the metabolic biodegradability was observed when fish waste was used, this effect being the highest for 25% of fish waste. In conclusion, metabolomics can be regarded as a promising tool both for characterizing the biochemical processes occurring during anaerobic digestion, and for providing a better understanding of the anaerobic digestion processes.

Degradation of azo dye Acid Red 14 (AR14) from aqueous solution using H2 O2 /nZVI and S2 O8 2- /nZVI processes in the presence of UV irradiation.

Azo dyes are mostly toxic and carcinogenic and cause harm to humans and the environment. This study was conducted to investigate the degradation of azo dye acid red 14 (AR14) from aqueous solution using hydrogen peroxide (H2 O2) /nano zerovalent iron (nZVI) and persulfate (S2 O8 2- )/nZVI processes in the presence of ultraviolet (UV) irradiation. This experimental study was carried out in a laboratory-scale batch photoreactor with a useful volume of 1 L. The nZVI was synthesized by the sodium borohydride (NaBH4 ) reduction method. In these processes, the effects of parameters including initial pH, H2 O2 concentration, S2 O8 2- concentration, nZVI dose, concentration of AR14 dye, and reaction time were studied. The results showed that decolorization increased by increasing the nZVI dosage, H2 O2 and S2 O4 2- concentrations, and reaction time, or decreasing dye concentration and pH. However, a too high oxidant concentration (H2 O2 and S2 O4 2- ) could inhibit the degradation. The experimental conditions for degradation of AR14 by UV/S2 O8 2- /nZVI and UV/H2 O2 /nZVI processes were as follows: [H2 O2 ]=10mM, [S2 O8 2- ]=8mM, AB14 dye=100mg/L, pH=3, and nZVI dose=0.05g. Under these conditions, the highest removal efficiencies of AR14, chemical oxygen demand (COD), and total organic carbon (TOC) for the UV/S2 O8 2- /nZVI process were 93.94%, 86.5%, and 81.6%, respectively, while these values were 89.3%, 79.57%, and 72.9% for the UV/H2 O2 /nZVI, respectively. Also, the average oxidation state (AOS) was decreased from 2.93 to 2.14 in the effluent of the UV/S2 O8 2- /nZVI process and from 2.93 to 2.2 for the UV/H2 O2 /nZVI process. The results showed that the ratio of biochemical oxygen demand (BOD5 ) to COD in the effluents of the UV/S2 O8 2 /nZVI and UV/H2 O2 /nZVI processes after 90min was 0.63 and 0.74, respectively. These findings suggest biodegradability improvement. PRACTITIONER POINTS: Photocatalytic degradation of azo dye Acid Red 14 (AR14) was achieved using H2 O2 /nZVI and S2 O8 2- /nZVI processes in the presence of UV irradiation. Effects of operating parameters on photocatalytic degradation AR14 dye were evaluated in the UV/H2 O2 /nZVI and UV/S2 O8 2- /nZVI processes. Biodegradability and mineralization studies of AR14 dye photocatalytic degradation were performed for the UV/H2 O2 /nZVI and UV/S2 O8 2- /nZVI processes.

Influence of Industrial Wastewater Quality on Advanced Treatment of Microbubble Ozonation

The treatment performance of microbubble ozonation used for advanced treatment of actual pharmaceutical wastewater and tannery wastewater was investigated and compared to show the influence of complicated wastewater quality. The results showed that most organic pollutants in pharmaceutical wastewater and tannery wastewater could be degraded by microbubble ozonation effectively. and COD was removed simultaneously. In addition, the biodegradability was improved and the bio-toxicity was eliminated significantly. The ratios of COD amount removed and ozone amount consumed were 0.77 and 1.02, respectively, in such advanced treatment of pharmaceutical wastewater and tannery wastewater, indicating different ozone oxidation efficiencies between pharmaceutical wastewater and tannery wastewater. The main types of organic pollutants in pharmaceutical wastewater and tannery wastewater were determined by GC-MS and 3D-EEM, which showed the influence on treatment performance of microbubble ozonation. More refractory complex aromatic organic pollutants were found in pharmaceutical wastewater, which seemed more difficult to undergo degradation by microbubble ozone oxidation. As a result, the microbubble ozone oxidation of pharmaceutical wastewater was less efficient than that of tannery wastewater. The inorganic anions in both kinds of wastewater were unfavorable for ozone mass transfer, ozone decomposition, and·OH generation, which reduced the reaction efficiency of microbubble ozonation as well as biodegradability improvement. The lower concentrations of inorganic anions were better for microbubble ozonation.

Fabrication and physical properties of a novel macroporous poly(vinyl alcohol)/cellulose fibre product

The objective of this work was to prepare functionalized cellulose fiber from sugar cane leaf (SCF) used to produce novel biomaterial. The SCF was treated with chloroacetic acid and sodium hydroxide (NaOH) to produce a modified cellulose fibre (MSCF). At higher MSCF loading, a greater porous density was observed under SEM. The addition of MSCF improved, the water resistance of the cured PVA/MSCF in both acid and base media through chemical reactions. The moisture absorption and moisture content of the cured PVA/MSCF film increased as the loading increased MSCF. Tg of the cured PVA/MSCF showed a clear decrease that was attributed to the greater molecular weight and softness of the molecular chains. The cured PVA/MSCF showed good MB absorption from wastewater. The improvement in biodegradability of the cured PVA/MSCF film may make it a candidate material for use in environmentally-sensitive applications.

Efficient treatment for landfill leachate through sequential electrocoagulation, electrooxidation and PMS/UV/CuFe2O4 process

Landfill leachate is well known as one of the most serious environmental problems due to the high concentrations of organic and inorganic compounds. Several methods have been reported for the treatment and detoxification of landfill leachate. However, high organic load and the presence of refractory organic pollutants resulted in inefficiency of those methods when at least applied alone. The present work recommended a sequence of processes: electrocoagulation (EC), electrooxidation (EO) and peroxymonosulfate (PMS)/UV/CuFe2O4 (sulfate radical-based advanced oxidation process, SR-AOP) for treatment of landfill leachate. A parametric evaluation was conducted for each process including pH, current densities, electrode type, catalyst loading, PMS dosage and reaction time. Al and Fe electrodes for the EC process and Pt, PbO2 and graphite for the EO process were investigated. The results showed that Fe and PbO2 were more efficient than other electrodes for EC and EO respectively. COD removal efficiencies were up to 60.0, 50.0 and 77.9% for EC, EO and SR-AOP, respectively. Removal efficiencies for the sequential process were 95.6, 90.5, 91.6 and 99.8% for COD, TOC, BOD and ammonia (NH4-N) respectively. Biodegradability was significantly enhanced according to the BOD/COD ratio and the average oxidation state of carbon (AOSC). Biodegradation test indicated that the organic matter was completely degraded by activated sludge in seven days. Phytotoxicity experiments also demonstrated a considerable reduction in phytotoxicity after each process. The results confirmed that the proposed sequence is efficient for COD removal, phytotoxicity reduction and biodegradability improvement being an acceptable treatment for landfill leachates.

Biodegradability enhancement and pre-treatment of industrial estate wastewater by electro-Fenton process

Advanced oxidation processes have been applied as one of the main commonly treatment methods to improve the biodegradability of persistent organic materials, especially in industrial wastewaters. In this study, the chemical oxygen demand (COD) and total oxygen carbon (TOC) removal efficiency and biodegradability improvement of the industrial estate wastewater were investigated by electro-Fenton process (EFP). The influences of various parameters including pH, H2O2 concentration, electrical current density, and reaction time were evaluated on the EFP. The maximum removal efficiency of COD (88) and TOC (80.8) was achieved at optimum pH 4, H2O2 concentration 13.5 mM, current density 5 mA cm(-2), and reaction time 20 min. The optimum H2O2/Fe2+ molar ratio was found to be 2. The biodegradability of the wastewater was increased from 0.23 to 0.39 after treatment by EFP under optimum conditions. The results showed that H2O2/Fe2+ molar ratio was the most important factor in the EFP system. The findings showed that the EFP can be considered as a suitable technique for pre-treatment and biodegradability enhancement of the industrial estate wastewater. So, this wastewater can be easily post-treated by biological treatment methods.

Degradation of refractory organic compounds from dinitrodiazophenol containingindustrial wastewater through UV/H2O2 and UV/PS processes.

In this study, refractory organic compounds from dinitrodiazophenol (DDNP) containing industrial wastewater were degraded through two ultraviolet (UV)-based advanced oxidation processes: UV/hydrogen peroxide (UV/H2O2) and UV/potassium persulfate (UV/PS) processes. In both processes, the synergistic effects, operational parameters (i.e., oxidant dosage and initial pH value), and pseudo first-order constant k were systematically studied. Moreover, the reactive oxygen species formed in the UV/H2O2 and UV/PS processes were identified, and the degradation of refractory organic compounds was characterized through UV-visible spectra analysis. The improvement in biodegradability of DDNP industrial wastewater after treatment by different processes was compared. Both the UV/H2O2 (synergistic coefficient F = 61.34) and UV/PS (synergistic coefficient F = 54.85) processes showed significant, highly synergistic effects. The increase in oxidant dosage was beneficial in organic compound removal in both the UV/H2O2 and UV/PS processes, but excessive H2O2 showed a stronger inhibition of the increase in organic compound removal than that in the UV/PS process. In addition, an acidic environment was more conducive to organic compound degradation in the UV/H2O2 process, whereas the initial pH value had less of an influence on the UV/PS process. Under optimal conditions for the UV/H2O2 and UV/PS processes, the CN and COD removal efficiencies were 99.71%, 66.35%, 99.69%, and 70.81%, respectively, and the k values for COD removal were 0.0804 and 0.0824min-1. Tests to identify reactive oxygen species showed that the hydroxyl radical was the predominant oxidizing species in the UV/H2O2 process, whereas the hydroxyl and sulfate radicals were both identified in the UV/PS process, and the sulfate radical contributed the most to the degradation of organic compounds. In addition, spectrum analysis revealed that the complex structure (e.g., benzene ring, nitro group, and diazo group) of refractory organic compounds from DDNP industrial wastewater was effectively destroyed by the UV/H2O2 and UV/PS processes, and both processes improved the biodegradability (biochemical oxygen demand for 5days/chemical oxygen demand (BOD5/COD)) of DDNP industrial wastewater from 0.052 to 0.665 and 0.717, respectively. Overall, both the UV/H2O2 and UV/PS processes effectively degraded the refractory organic compounds from DDNP industrial wastewater, and the UV/PS process exhibited a higher organic compound removal efficiency and better applicability.

Treatment of fish processing industry wastewater using hydrodynamic cavitational reactor with biodegradability improvement.

Water generated from the fish processing industry is contaminated with organic matter. This organic matter present in wastewater increases the biochemical oxygen demand (BOD) and chemical oxygen demand (COD). A new technology, hydrodynamic cavitation (HC) is used to deal with this wastewater produced in fish processing plants. The orifice plate is used in the HC reactor to generate a cavitation effect. The intensification of this technique was carried out with the help of hydrogen peroxide (H2O2) and TiO2. The treatment of this wastewater is reported in terms of percent degradation in BOD and COD and in biodegradability index (BI). Operating parameters like inlet pressure, pH, operating temperature and H2O2 doses were used to find the optimum condition. 15 g/L of H2O2 gave 69.5% reduction of COD in the 120 min of treatment that also increases BI value to 0.93 at inlet pressure 8 bar, Plate-5, temperature (30 °C), and pH 4. In the ultrasonic cavitation (UC) reactor, COD reduction is 68.7% without TiO2 and with TiO2 it is 71.2%. Also, this HC and UC reactor reduced CFU count to a great extent at the same operating conditions.

Glucose cross-linked hydrogels conjugate HA nanorods as bone scaffolds: Green synthesis, characterization and in vitro studies

In the expanding field of tissue engineering (TE), improvement of biodegradability and osteoconductivity of biomaterials are required. The use of non-toxic reagents during manufacturing processes is also necessary to decrease toxicity and increase cell viability in vivo. Herein, we present a novel approach to prepare hydroxyapatite (HA) nanorods from sea bio-wastes through a green and eco-friendly wet-chemical processing for bone TE. Highly porous natural polymer-ceramic nanocomposites made of HA, gelatin (Ge) and carboxymethyl cellulose (CMC) hydrogels are then introduced. It was found that cross-linking of the hydrogel matrix by glucose as a green reagent affected all characteristics of the scaffolds including pore size, swelling, biodegradability, and mechanical properties. The homogeneous microstructure with pore sizes in the range of 100–200 μm were attained at 10–20 wt% glucose concentration. With regard to stability and swelling in phosphate buffer saline (PBS), however, more glucose concentrations were desirable. The high biocompatibility and osteoblast activity of the scaffolds were assayed by MTT and calcium content on cell-cultured scaffolds with mesenchymal stem cells (MSCs). The developed CMC/Ge hydrogels modified with bio-derived HA nanorods have a great potential to be used for non-load bearing applications in bone TE.

Biodegradability improvement and toxicity reduction of soil washing effluents polluted with atrazine by means of electrochemical pre-treatment: Influence of the anode material

This work focuses on the partial anodic electro-oxidation of atrazine-polluted soil washing effluents (SWE) in order to reduce its toxicity and to improve its biodegradability. Concretely it has been evaluated the influence of the anodic material used. It is hypothesized that such partial oxidation step could be considered as a pre-treatment for a subsequent biological treatment. At first, atrazine was extracted from a polluted soil by means of a surfactant-aided soil-washing process. Then, four different anodic materials were studied in partial electro-oxidation pre-treatment batch experiments at different electric charges applied: Boron Doped Diamond (BDD), Carbon Felt (CF), and Mixed Metal Oxides Anodes with Iridium and Ruthenium. Atrazine, TOC, surfactant and sulphate species concentrations, as well as changes in toxicity and biodegradability, were monitored during electrochemical experiments, showing important differences in their evolution during the treatment. It was observed that BDD was the most powerful anodic material to completely degrade atrazine. The other materials achieve an atrazine degradation rate about 75%. Regarding mineralization of the organics in SWE, BDD overtakes clearly the rest of anodes tested. CF obtains good atrazine removal but low mineralization results. All the anodes tested slightly reduced the ecotoxicity of the water effluents. About the biodegradability, only the effluent obtained after the pre-treatment with BDD presented a high biodegradability. In this sense, it must be highlighted the mineralization obtained during the BDD pre-treatment was very strong. These results globally indicate that it is necessary to find a compromise between reaching efficient atrazine removal and biodegradability improvement, while also simultaneously avoiding strong mineralization. Additional efforts should be made to find the most adequate working conditions.