15 research outputs found
Comparative Assessment of Shrimp Hydrolyzates as Alternative Organic Fertilizers for Legumes
The global annual production of shrimp is nearly 4Â million metric tons generating almost half of this weight in waste. This study assessed the crop production of legumes fertilized with shrimp exoskeletons obtained by microwaves under greenhouse conditions. Plants were grown under the following fertilization regimes: (i) untreated shrimp waste, (ii) shrimp waste pellets, (iii) shrimp-based pellets having a hydrolysis degree of 42%, (iv) untreated cellulose pellets, (v) untreated soil, (vi) untreated cotton substrate, and (vii) two commercial fertilizers (CF1 and CF2). CF1 and CF2 showed the largest electric conductivity and ionic exchange capability, whereas the fertilizing pellets showed the lowest values. However, pH, densification and conductivity of soil were not affected by fertilization. Shrimp waste showed a high content of C, N, O, Ca and P mainly derived from chitin, proteins and minerals. All fertilizers showed typical type II isotherms, but the untreated soil and CF2 per se exhibited the largest water uptake. The soil microbiota increased during the growing cycle and then decreased as the reproductive phase started. Further, soil planted with Phaseolus vulgaris showed a larger microbial population than Pisum sativum. The best plant growth was achieved when treated with CF2, whereas the raw shrimp waste caused a beneficial plant growth and crop yield mainly in Phaseolus vulgaris
Methods involved in the treatment of four representative pharmaceuticals in hospital wastewater using sonochemical and biological processes
A primary pollution source by pharmaceuticals is hospital wastewater (HWW). Herein, the methods involved in the action of a biological system (BS, aerobic activated sludge) or a sonochemical
treatment (US, 375 kHz and 30.8 W), for degrading four relevant pharmaceuticals (azithromycin,
ciprofloxacin, paracetamol, and valsartan) in HWW, are shown. Before treatment of HWW, the
correct performance of BS was assessed using glucose as a reference substance, monitoring oxygen consumption, and organic carbon removal. Meanwhile, for US, a preliminary test using
ciprofloxacin in distilled water was carried out. The determination of risk quotients (RQ) and
theoretical analyses about reactive moieties on these target substances are also presented. For
both, the degradation of the pharmaceuticals and the calculation of RQ, analyses were performed
by LC-MS/MS. The BS action decreased the concentration of paracetamol and valsartan by âŒ96
and 86%, respectively. However, a poor action on azithromycin (2% removal) was found, whereas
ciprofloxacin concentration increased âŒ20%; leading to an RQ value of 1.61 (high risk) for the
pharmaceuticals mixture. The analyses using a biodegradation pathway predictor (EAWAG-BDD
methodology) revealed that the amide group on paracetamol and alkyl moieties on valsartan
could experience aerobic biotransformations. In turn, US action decreased the concentration of
the four pharmaceuticals (removals > 60% for azithromycin, ciprofloxacin, and paracetamol),
diminishing the environmental risk (RQ: 0.51 for the target pharmaceuticals mixture). Atomic
charge analyses (based on the electronegativity equalization method) were performed, showing
that the amino-sugar on azithromycin; piperazyl ring, and double bond close to the two carbonyls
on ciprofloxacin, acetamide group on paracetamol, and the alkyl moieties bonded to the amide
group of valsartan are the most susceptible moieties to attacks by sonogenerated radicals. The
LC-MS/MS analytical methodology, RQ calculations, and theoretical analyses allowed for determining the degrading performance of BS and US toward the target pollutants in HWW
Comparative study of the effect of pharmaceutical additives on the elimination of antibiotic activity during the treatment of oxacillin in water by the photo-Fenton, TiO2-photocatalysis and electrochemical processes
ABSTRACT: Synthetic pharmaceutical effluents loaded with the ÎČ-lactam antibiotic oxacillin were treated using advanced oxidation processes (the photo-Fenton system and TiO2 photocatalysis) and chloride mediated electrochemical oxidation (with Ti/IrO2 anodes). Combinations of the antibiotic with excipients (mannitol or tartaric acid), an active ingredient (calcium carbonate, i.e. bicarbonate ions due to the pH) and a cleaning agent (sodium lauryl ether sulfate) were considered. Additionally, urban wastewater that had undergone biological treatment was doped with oxacillin and treated with the tested systems. The evolution of antimicrobial activity was monitored as a parameter of processes efficiency. Although the two advanced oxidation processes (AOPs) differ only in the way they produce OH, marked differences were observed between them. There were also differences between the AOPs and the electrochemical system. Interestingly, each additive had a different effect on each treatment. For water loaded with mannitol, electrochemical treatment was the most suitable option because the additive did not significantly affect the efficiency of the system. Due to the formation of a complex with Fe3 +, tartaric acid accelerated the elimination of antibiotic activity during the photo-Fenton process. For TiO2 photocatalysis, the presence of bicarbonate ions contributed to antibiotic activity elimination through the possible formation of carbonate and bicarbonate radicals. Sodium lauryl ether sulfate negatively affected all of the processes. However, due to the higher selectivity of HOCl compared with OH, electrochemical oxidation showed the least inhibited efficiency. For the urban wastewater doped with oxacillin, TiO2 photocatalysis was the most efficient process. These results will help select the most suitable technology for the treatment of water polluted with ÎČ-lactam antibiotics
Improvement of the carbocatalytic degradation of pharmaceuticals in water by the use of ultrasound waves
A carbonaceous material obtained from wood wastes (SW-Mn) was initially used for the removal of pharmaceuticals in water by a carbocatalytic system. The SW-Mn material adsorbed only 41% of the diclofenac (DCF) and 3% of the valsartan (VAL). Interestingly, SW-Mn activated peroxymonosulfate (PMS) and presented a significant increase in the removal rate of DCF, surpassing 90%, while VAL achieved a 24% removal rate at 20 min of treatment. The carbonaceous material was not effective in activating peroxydisulfate or hydrogen peroxide. Nevertheless, the addition of ultrasound waves at 40 kHz to the carbocatalytic system (SW-Mn +PMS) significantly enhanced VAL degradation, exhibiting a high synergy index (4.98). The routes of the degradation were determined using scavengers, and XPS and EPR analyses, evidencing the main action of singlet oxygen in both carbocatalytic and sonocarbocatalytic systems. It is important to note that radicals also participated in the sonocarbocatalytic process, albeit with a minor contribution. The reuse of SW-Mn was tested during various cycles, showing up to a 39.2% VAL degradation rate after the third consecutive reuse. Moreover, the sonocarbocatalytic system was applied to a sample of irrigation crop water spiked with VAL. The treatment induced a partial elimination of the pollutant due to some interfering effects of the matrix components
Selecting the best AOP for isoxazolyl penicillins degradation as a function of water characteristics: Effects of pH, chemical nature of additives and pollutant concentration
To provide new insights toward the selection of the most suitable AOP for isoxazolyl penicillins elimination, the degradation of dicloxacillin, a isoxazolyl penicillin model, was studied using different advanced oxidation processes (AOPs): ultrasound (US), photo-Fenton (UV/H2O2/Fe2+) and TiO2 photo catalysis (UV/TiO2). Although all processes achieved total removal of the antibiotic and antimicrobial activity, and increased the biodegradability level of the solutions, significant differences concerning the mineralization extend, the pH of the solution, the pollutant concentration and the chemical nature of additives were found. UV/TiO2 reached almost complete mineralization; while 10% mineralization was obtained for UV/H2O2/Fe2+ and practically zero for US. Effect of initial pH, mineral natural water and the presence of organic (glucose, 2-propanol and oxalic acid) were then investigated. UV/H2O2/Fe2+ and US processes were improved in acidic media, while natural pH favored UV/TiO2 system. According to both the nature of the added organic compound and the process, inhibition, no effect or enhancement of the degradation rate was observed. The degradation in natural mineral water showed contrasting results according to the antibiotic concentration: US process was enhanced at low concentration of dicloxacillin followed by detrimental effects at high substrate concentrations. A contrary effect was observed during photo-Fenton, while UV/TiO2 was inhibited in all of cases. Finally, a schema illustrating the enhancement or inhibiting effects of water matrix is proposed as a tool for selecting the best process for isoxazolyl penicillins degradation. (C) 2016 Elsevier Ltd. All rights reserved
Comparative degradation of indigo carmine by electrochemical oxidation and advanced oxidation processes
ABSTRACT: The remediation of aqueous effluents containing indigo carmine (IC), a highly toxic indigoid dye used
as a textile coloring agent and an additive in pharmaceutical tablets and capsules, was studied using
four promising technologies: Ultrasound (US), photo-Fenton (PF), TiO2 photocatalysis (TiO2/UV) and
electrochemical oxidation with Ti/IrO2-SnO2-Sb2O5 as anode (EO). The main degradation pathway was
determined for each system tested. Additionally, the comparative effects of initial pH and presence of
chloride ions was investigated. The results showed that EO of IC was mediated by chloride, whereas IC
degradation by TiO2/UV occurred directly in valence band holes of the catalyst. However, with PF and
US systems hydroxyl radicals OH played the main role. In spite of the different degradation pathways,
acidic pH increased the performance of all systems. The presence of chloride favored the efficiency of EO,
but inhibited the IC removal by PF, as well as the elimination of Chemical Oxygen Demand (COD) by US
and TiO2/UV. The results showed that, under working conditions, EO with Ti/IrO2-SnO2-Sb2O5 anodes is
the best option to treat IC in effluents containing a significant concentration of chloride ion
Kinetics, Isotherms and Thermodynamic Modeling of Liquid Phase Adsorption of Crystal Violet Dye onto Shrimp-Waste in Its Raw, Pyrolyzed Material and Activated Charcoals
Shrimp waste and its charcoal derivatives were evaluated for the removal of crystal violet. Activation was conducted at 500 °C with phosphoric acid at the 1:2 and 1:3 ratios. Activated charcoals were more porous and had a more roughly surface containing mainly C, O, Ca N, and P. Equilibrium adsorption data were fitted using seven kinetic and six isotherms models. Activation created acidic moieties (>4700 µmol/g) and reduced the point of zero charge (<2.5). Freundlich isotherm best described the uptake of the dye onto the adsorbents suggesting a heterogeneous adsorption, whereas the Bangham and Avrami models best described the kinetics of adsorption process. An endothermic and spontaneous physisorption was responsible for the sorption phenomena in most adsorbents. The high removal of crystal violet was attributed to the high ionization capacity of the adsorbent coupled with the high external surface area (>44 m2/g). The best adsorption capacity (208 mg/g) was found for the activated and charred materials, whereas the lowest one (3.9 mg/g) was found for the pyrolyzed material. This research creates the possibility to deal with two environmental problems: (i) the reuse of shrimp waste and (ii) the removal of water pollutants such as crystal violet
Elimination of the antibiotic norfloxacin in municipal wastewater, urine and seawater by electrochemical oxidation on IrO2 anodes
The electrochemical degradation of the fluoroquinolone antibiotic norfloxacin (NOR) on Ti/IrO2 anodes, in several aqueous matrices was evaluated. For this purpose, initially the performance and degradation routes of the technology at several pH values (3.0, 6.5, 7.5 and 9.0) and in the presence of some of the most common anions in real water matrices (Clâ, HCO3â, SO4 2â and NO3â) were determined. The results showed that the degradation of NOR can occur through both direct elimination at the electrode surface and mediated oxidation, via the electrogeneration of oxidative agents, such as active chlorine species and percarbonate ions, which come from chloride and bicarbonate oxidation, respectively. Conversely, nitrate ions showed to inhibit the efficiency of the system. Concerning the pH, the efficiency of the process in the presence of chloride ions followed the order: 9.0 > 7.5 > 6.5 > 3.0; showing a strong dependence of the NOR speciation, and being the anionic form of the antibiotic the more susceptible to be oxidized. Furthermore, the identification of three primary NOR by-products demonstrated that the initial attack of the active chlorine species, mainly HOCl, occurred at the secondary amine of the piperazine ring followed by chlorination of the benzene ring. The precedent findings were crucial to understand the efficiency of the technology to eliminate NOR in synthetic complex matrices such as seawater, municipal wastewater and urine. The electrochemical oxidation showed to be promissory to eliminate NOR, and its associated antimicrobial activity, in such complexes matrices. Waters at basic pH containing chloride or bicarbonate ions, such as seawater or municipal wastewater showed to be the most adapted to the application of the technology. Additionally, nitrate ions or urea, found in some matrices like fresh urine, reduce the efficiency of the process
Possibilities and Limitations of the Sono-Fenton Process Using Mid-High-Frequency Ultrasound for the Degradation of Organic Pollutants
Mid-high-frequency ultrasound (200â1000 kHz) eliminates organic pollutants and also generates H2O2. To take advantage of H2O2, iron species can be added, generating a hybrid sono-Fenton process (sF). This paper presents the possibilities and limitations of sF. Heterogeneous (a natural mineral) and homogeneous (Fe2+ and Fe3+ ions) iron sources were considered. Acetaminophen, ciprofloxacin, and methyl orange were the target organic pollutants. Ultrasound alone induced the pollutants degradation, and the dual competing role of the natural mineral (0.02â0.20 g Lâ1) meant that it had no significant effects on the elimination of pollutants. In contrast, both Fe2+ and Fe3+ ions enhanced the pollutantsâ degradation, and the elimination using Fe2+ was better because of its higher reactivity toward H2O2. However, the enhancement decreased at high Fe2+ concentrations (e.g., 5 mg Lâ1) because of scavenger effects. The Fe2+ addition significantly accelerated the elimination of acetaminophen and methyl orange. For ciprofloxacin, at short treatment times, the degradation was enhanced, but the pollutant complexation with Fe3+ that came from the Fenton reaction caused degradation to stop. Additionally, sF did not decrease the antimicrobial activity associated with ciprofloxacin, whereas ultrasound alone did. Therefore, the chemical structure of the pollutant plays a crucial role in the feasibility of the sF process
Effective elimination of fifteen relevant pharmaceuticals in hospital wastewater from Colombia by combination of a biological system with a sonochemical process
This work presents the treatment of selected emerging concern pharmaceuticals in real hospital wastewater (HWW) from Tumaco-Colombia by combination of a biological system with a sonochemical process. Fifteen compounds, commonly present in HWW, were considered: acetaminophen, diclofenac, carbamazepine, venlafaxine, loratadine, ciprofloxacin, norfloxacin, valsartan, irbesartan, sulfamethoxazole, trimethoprim, clarithromycin, azithromycin, erythromycin and clindamycin. Initially, HWW was characterized in terms of global parameters and the pharmaceuticals content. HWW contained a moderate amount of organic matter (i.e., total organic carbon: 131.56âŻmgâŻLâ1 (C)) mainly associated to biodegradable components. However, the most of pharmaceuticals were found at levels upper than their predicted no effect concentration (PNEC). Then, a conventional biological treatment was applied to the HWW. After 36âŻh, such process mainly removed biodegradable substances, but had a limited action on the pharmaceuticals. The resultant biotreated water was submitted to the sonochemical process (375âŻkHz and 88âŻWâŻLâ1, 1.5âŻh), which due to its chemical (i.e., radical attacks) and physical (i.e., suspended solids disaggregation) effects induced a considerable pharmaceuticals degradation (pondered removal: 58.82%), demonstrating the complementarity of the proposed combination. Afterwards, Fe2+ (5âŻppm) and UVC light (4âŻW) were added to the sonochemical system (generating sono-photo-Fenton process), which significantly increased up to 82.86% the pondered pharmaceuticals removal. Subsequently, to understand fundamental aspects of the pharmaceuticals degradations, a model compound (norfloxacin) in distilled water was treated by sonochemical system, sono-photo-Fenton process and their sub-systems (i.e., sono-Fenton and UVC alone). This allowed proving the hydroxyl radical action in sonochemical treatment, plus the contribution of Fenton reaction and direct photodegradation in the pharmaceuticals removal by sono-photo-Fenton. Finally, it was found that 91.13% of the initial pharmaceuticals load in HWW was removed by the biological/sono-photo-Fenton combination. The high pollutants abatement evidenced that this combination is a powerful alternative for removing pharmaceuticals from complex-matrix waters, such as raw HWW