Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 571
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Chemosphere ; 240: 124889, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31563102

RESUMO

This study explores the use of an engineered char produced from the pyrolysis of anaerobically digested fiber (ADF) to adsorb phosphate from aqueous solutions. Two series of engineered chars were produced. The first series was a CO2 activated (CA) char produced via slow pyrolysis between 350 and 750 °C. The second series was a nitrogen doped (ND) char activated in the presence of ammonia at comparable temperatures. Proximate analysis, elemental composition, gas physisorption, Inductively coupled plasma mass spectrometry (ICP-MS), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray powder diffraction (XRD) techniques were used to characterize properties of resulting products. The surface area of the carbon product increased after nitrogen doping through ammonization (166.6-463.1 m2/g) compared to CO2 activated chars (156.5-413.1 m2/g). Phosphate adsorption isotherms for both CO2 activated and nitrogen doped chars can be described by the Langmuir- Freundlich and Redlich Peterson adsorption models. Nitrogen doped carbon phosphate sorption capacity in aqueous solutions was twice compared to CO2 activated carbons. As carbonization/activation temperature increased the sorption capacity increased from 3.4 to 33.3 mg g-1 for CA char and 6.3-63.1 mg g-1 for nitrogen doped char.


Assuntos
Carvão Vegetal/química , Nitrogênio/química , Fosfatos/análise , Fosfatos/isolamento & purificação , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/isolamento & purificação
2.
Huan Jing Ke Xue ; 40(7): 3179-3185, 2019 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854716

RESUMO

In a cyclic alternating O/A operation mode, phosphorus accumulating organisms (PAOs) can undertake phosphate removal and enrichment as the main process in wastewater treatment plants. The effects of the concentration of carbon sources during the aerobic stage on phosphate removal and enrichment performance of PAO biofilms, and the microbial population structure in the biofilms, were investigated. The results showed that the aerobic COD concentration decreased from 200 mg·L-1 to 0 mg·L-1, the phosphorus uptake rate improved by 1.29 times, the phosphorus concentration in effluent stabilized below 0.5 mg·L-1, the phosphorus release rate increased by 3.56 times, and the phosphate concentration in the circulating solution increased from 27.125 mg·L-1 to 55.91 mg·L-1. With respect to the change in microbial communities, the identification showed that the abundance of Proteobacteria increased by approximately two times, and the enrichment effects of Rhodocyclaceae and Anaerolineaceae increased by 2.28 and 5 times, respectively. Reducing the concentration of the carbon source in the aerobic section was beneficial to the screening and enrichment of PAOs, strengthening the removal of phosphate in the aerobic section and the release of phosphate in the anaerobic section. This resulted in an enriched phosphate solution. These observations provide a theoretical basis for future urban sewage treatment plants seeking to reduce their carbon demand.


Assuntos
Biofilmes , Carbono , Fosfatos/isolamento & purificação , Eliminação de Resíduos Líquidos , Análise da Demanda Biológica de Oxigênio , Reatores Biológicos/microbiologia , Fósforo , Proteobactérias , Rhodocyclaceae , Esgotos
3.
Chemosphere ; 235: 1015-1021, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31561290

RESUMO

Phosphate is one of the main contaminations in water, so an effective method of decreasing or removing phosphate is needed. The main purpose of this paper is to synthesize CaFe-LDHs and MgFe-LDHs from the mixture of calcined dolomite and ferric chloride to remove orthophosphate and pyrophosphate. The study showed that removal of orthophosphate was attributed to the precipitation by Ca2+ and adsorption by MgFe-LDHs, where the former played a main role. As for pyrophosphate, it was mainly removed by precipitation at the initial pyrophosphate concentration ranging from 3.228 to 17.04 mmol/L. When the initial concentrations became relatively higher, the removal efficiency of pyrophosphate decreased because the complexation effects by Fe3+, Ca2+ and Mg2+ took place.


Assuntos
Carbonato de Cálcio/química , Cloretos/química , Difosfatos/análise , Compostos Férricos/química , Hidróxidos/química , Magnésio/química , Fosfatos/análise , Poluentes Químicos da Água/análise , Difosfatos/isolamento & purificação , Fosfatos/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos
4.
Environ Sci Pollut Res Int ; 26(29): 30452-30462, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31444717

RESUMO

This study investigates the feasibility of recovery of phosphorus via struvite precipitation from a synthetic anaerobically treated distillery spent wash by optimizing the process using a chemical equilibrium model, namely Visual MINTEQ. Process parameters such as Mg2+, [Formula: see text], and [Formula: see text] ion concentrations and pH were used as inputs into the model. Increasing the molar ratio of [Formula: see text] from 0.8:1 to 1.6:1 at pH 9 led to an increase in phosphate recovery from 88.2 to 99.5%. The model and experimental results were in good agreement in terms of phosphate recovery, indicating that the Visual MINTEQ model can be used to pre-determine the process parameters for struvite synthesis. Increasing the concentration of calcium ion adversely affected the synthesis and purity of struvite, whereas the presence of melanoidins had no significant impact. This study demonstrates that phosphorus recovery through struvite precipitation is a sustainable approach to reclaim phosphorus from high-strength industrial wastewater.


Assuntos
Fosfatos/isolamento & purificação , Estruvita/química , Eliminação de Resíduos Líquidos/métodos , Precipitação Química , Destilação , Indústria Alimentícia , Concentração de Íons de Hidrogênio , Magnésio/química , Modelos Químicos , Fósforo/química , Fósforo/isolamento & purificação , Águas Residuárias/química
5.
Artigo em Inglês | MEDLINE | ID: mdl-31328626

RESUMO

Four low-cost materials, oyster shells, pumice stone, sand and zeolite were employed as adsorbents in an adsorption batch assays investigating the removal of ammonia, phosphate and nitrate from an aqueous solution. These compounds were chosen as they represent typical compounds found in landfill leachate (LFL). Assay performance was evaluated by the Langmuir and Freundlich adsorption isotherms. The top two materials, oyster shells and pumice stone, were employed as adsorbents in a fixed-bed column trial examining the effect of bed height and flow rate on the treatment of a synthetic LFL. The trial concluded that the highest rates of adsorption were achieved using bed heights of 20 cm with a flow rate of 5 mL min-1. After optimization, the system was employed for the treatment of LFL from Powerstown landfill, Carlow, Ireland. Ammonia and nitrate were effectively removed by both adsorption materials resulting in a reduction of influent ammonia and nitrate concentrations to below the national discharge limits set for these compounds of ≤4 mg L-1 and ≤50 mg L-1, respectively. In contrast, although similar high removal efficiencies were observed for phosphate, these rates were not maintained during the test period with overall results indicating reduced phosphate adsorption in comparison to the other compounds tested.


Assuntos
Amônia/isolamento & purificação , Nitratos/isolamento & purificação , Fosfatos/isolamento & purificação , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Amônia/química , Exoesqueleto/química , Animais , Irlanda , Nitratos/química , Fosfatos/química , Silicatos/química , Eliminação de Resíduos Líquidos/economia , Poluentes Químicos da Água/química , Poluentes Químicos da Água/economia
6.
Environ Sci Pollut Res Int ; 26(18): 18343-18353, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31044376

RESUMO

ZnAl-layered double hydroxide-loaded banana straw biochar (ZnAl-LDH-BSB) was prepared via the hydrothermal method, and the efficient phosphorus removal agent ZnAl-LDO-BSB was obtained by calcination at 500 °C. Based on the ZnAl-LDO-BSB adsorption characteristics, the adsorption mechanism was evaluated via TG/DTA, FTIR, XRD, SEM, HRTEM, and other characterization methods. The results showed that the ZnAl-LDO-BSB assembled into microspheres with typical hexagonal lamellar structures and presented good thermal stability. The adsorption of total phosphate (TP) by ZnAl-LDO-BSB conforms to the Langmuir model, and the theoretical maximum adsorption capacity is 185.19 mg g-1. The adsorption kinetics were in accordance with the second-order kinetic model, and the anion influence on TP adsorption followed the order CO32- > SO42- > NO3-. The combination of zeta potential measurements with the FTIR, XRD, SEM, HRTEM, and XPS results suggested that ZnAl-LDO-BSB adsorbs TP mainly by electrostatic adsorption, surface coordination, and anion intercalation. Graphical abstract.


Assuntos
Alumínio/química , Carvão Vegetal , Musa , Fosfatos/química , Águas Residuárias/química , Purificação da Água/métodos , Zinco/química , Adsorção , Hidróxidos/química , Cinética , Fosfatos/isolamento & purificação
7.
Environ Sci Pollut Res Int ; 26(16): 16568-16576, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30989609

RESUMO

Given the prevalence of nitrate and phosphate in surface and groundwater, it is important to develop technology for the simultaneous removal of nitrate and phosphate. In this study, we prepared the bimetallic nanoparticles of Fe coupled with copper or nickel supported on chelating resin DOW 3N (D-Fe/Ni and D-Fe/Cu) for removing nitrate and phosphate simultaneously. XPS profiles revealed that Cu has better ability than Ni to increase the stability of Fe nanoparticles and prevent nZVI from oxidation. The results showed that nitrate removal efficiencies by D-Fe/Ni and D-Fe/Cu were 98.7% and 95.5%, respectively and the phosphate removal efficiencies of D-Fe/Cu and D-Fe/Ni were 99.0% and 93.0%, respectively. Besides adsorption and coprecipitation as reported in previous studies, the mechanism of phosphate removal also includes the adsorption of the newly formed polymeric ligand exchanger (PLE). Moreover, in previous studies, the presence of phosphate had significant negative effects on the reduction of nitrate. However, in this study, the removal efficiency of nitrate was less affected with the increasing concentration of phosphate for D-Fe/Cu. This was mainly because D-Fe/Cu had higher adsorption capacity of phosphate due to the newly formed PLE according to the XPS depth profile analysis.


Assuntos
Água Subterrânea/química , Ferro/química , Nanopartículas Metálicas/química , Nitratos/isolamento & purificação , Fosfatos/isolamento & purificação , Purificação da Água/métodos , Adsorção , Cobre/química , Níquel/química , Nitratos/análise , Oxirredução , Fosfatos/análise , Poluentes Químicos da Água/isolamento & purificação
8.
Chemosphere ; 226: 246-258, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30933734

RESUMO

Due to the shortage of phosphorus resources and the limitations of existing phosphorus recovery methods, phosphorus recovery in the form of vivianite has attracted considerable attention with its natural ubiquity, easy accessibility and foreseeable economic value. This review systematically summarizes the chemistry of vivianite, including the characteristics, formation process and influencing factors of the material. Additionally, the potential of phosphorus recovery as vivianite from wastewater has also been comprehensively examined from the prospects of economic value and engineering feasibility. In general, this method is theoretically and practically feasible, and brings some extra benefits in WWTPs. However, the insufficient understanding on vivianite recovery in wastewater/sludge decelerate the development and exploration of such advanced approach. Further researches and cross-field supports would facilitate the improvement of this technique in the future.


Assuntos
Compostos Ferrosos/química , Fosfatos/química , Fósforo/isolamento & purificação , Águas Residuárias/química , Compostos Ferrosos/isolamento & purificação , Fosfatos/isolamento & purificação , Reciclagem/métodos
9.
Water Environ Res ; 91(8): 797-804, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30993735

RESUMO

The recovery and reuse of phosphorus (P) from wastewater treatment process is a critical and viable target for sustainable P utilization. This study explores a novel approach of integrating ultrafine mineral particles into hydrogel matrixes for enhancing the capacity of phosphate adsorption. Dolomite-alginate (DA) hydrogel beads were prepared by integrating ball-milled, ultrafine dolomite powders into calcium cross-linked alginate hydrogel matrix. The adsorption isotherms followed a Langmuir-Freundlich adsorption model with higher specific adsorption capacity than those reported in literature. The kinetics of phosphate adsorption suggest that the adsorption is diffusion controlled. Investigation of adsorption capacity at different pH showed a maximum adsorption capacity in the pH range of 7-10. Lastly, we demonstrated that the DA beads are capable of slowly releasing most of the adsorbed phosphate, which is an important criterion for them to be an effective phosphorous fertilizer. This study, using DA composite hydrogel as an example, demonstrates a promising strategy of immobilizing ultrafine mineral adsorbents into biocompatible hydrogel matrix for effective recovery of phosphorous resource from wastewater. PRACTITIONER POINTS: Integration of dolomite and alginate hydrogel beads is demonstrated using ball milling. Ball milling process increases the specific adsorption capacity of dolomite on phosphorus. Adsorption isotherms, kinetics, and pH effects of the dolomite-alginate beads are investigated. The dolomite-alginate beads can be used as slow-release phosphorus fertilizer.


Assuntos
Alginatos/química , Carbonato de Cálcio/química , Fertilizantes , Magnésio/química , Fosfatos/isolamento & purificação , Adsorção
10.
Chemosphere ; 225: 352-359, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30884296

RESUMO

Phosphate adsorption on suspended sediments is largely influenced by the variations in salinity and pH such as is the case in estuaries where freshwater mixes with seawater, exhibiting strong physico-chemical gradients. In this research, the influence of salinity and pH on the adsorption of phosphate on hydrous ferric oxides (HFO) was investigated in NaCl solutions. The adsorption isotherm data at different salinities can be well fitted with the Langmuir-Freundlich model. At pH 8.5 the maximum adsorption capacity increases with increasing salinity, from 22.7 mg PO4/g at salinity 0-78.5 mg PO4/g at salinity 35 PSU (Practical Salinity Unit) with the largest increase occurring in the low salinity range (76.8 mg PO4/g at salinity 5 PSU). Phosphate adsorption is also highly pH dependent and the adsorption capacity decreases with increasing pH. The dependence of phosphate adsorption on salinity could be attributed to the inner-sphere complexation. The presence of Na+ modifies the phosphate speciation, which can also facilitate phosphate adsorption. Fourier-transform infrared spectroscopy (FTIR) results show that both bidentate (≡Fe2PO4) and monodentate (≡FePO4) complexes are formed during phosphate adsorption on HFO surface. Quantitative relationships between phosphate adsorption and salinity are proposed for the different pHs investigated in this study, which is important for the understanding of the phosphate adsorption dynamics during estuarine mixing.


Assuntos
Compostos Férricos/química , Fosfatos/química , Adsorção , Estuários , Concentração de Íons de Hidrogênio , Fosfatos/isolamento & purificação , Salinidade , Cloreto de Sódio , Soluções/química , Espectroscopia de Infravermelho com Transformada de Fourier
11.
Water Environ Res ; 91(7): 606-615, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30737846

RESUMO

Nutrient recovery from municipal wastewater was evaluated using anion exchange media loaded with hydrated ferric oxide (HFO) and copper (Cu2+ ) (Dow-HFO-Cu resin) to selectively capture phosphate, followed by clinoptilolite for ammonium removal and recovery. Nutrients were concentrated in the regenerants and recovered as precipitated struvite. Media exchange capacity after multiple ion exchange cycles was determined using permeate from an anaerobic membrane bioreactor (AnMBR) treating synthetic or actual municipal wastewater from a full-scale water reclamation facility. Regeneration through five ion exchange cycles using relatively low concentration regenerant solution (2% NaCl and 0.5% NaOH) resulted in the highest phosphate exchange capacity and phosphate recovery. This regenerant also provided the most consistent ammonium recovery. Column tests treating AnMBR permeate were performed over five ion exchange cycles; Dow-HFO-Cu resin exchange capacities ranged from 1.6 to 2.8 mg PO4 -P/g dry media. A maximum of 94% of the removed phosphate was recovered during regeneration. The rate and extent of regeneration was insensitive to regenerant salt concentrations in the range investigated. Precipitation using a mixture of the spent regeneration brines from the Dow-HFO-Cu resin and clinoptilolite columns produced low molar ratios of Mg:NH4 :PO4 , suggesting that the recovered product was not pure struvite. PRACTITIONER POINTS: Ion exchange-precipitation for the removal and recovery of PO 4 3 - and NH4 + from AnMBR permeate is a promising technology. 2% NaCl + 0.5% NaOH regeneration solution provided the most consistent exchange performance for both phosphate and ammonium recovery. Regenerated Dow-HFO-Cu resin exchange capacity was consistently less than the virgin resin, likely due to copper leaching during regeneration. Molar ratios in the precipitates suggested that the precipitated material was not pure struvite.


Assuntos
Compostos de Amônio/isolamento & purificação , Resinas de Troca Iônica/química , Fosfatos/isolamento & purificação , Gerenciamento de Resíduos/métodos , Zeolitas/química , Anaerobiose , Reatores Biológicos , Membranas Artificiais
12.
Water Environ Res ; 91(8): 672-678, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30793418

RESUMO

A combined process of the upflow multimedium biological aerated filter (UMBAF) and the multimedia biological aerated filter (MBAF) treating detergent wastewater was investigated in this study. Results showed that the optimal filtration rate of the combined system was 1.4 m/hr while the optimized performance was observed at air to water ratio of 2:1. The average removal rate of chemical oxygen demand (COD), linear alkyl benzene sulfonate sodium (LAS), and total phosphate (TP) was up to 91.4%, 88.5%, and 40%, respectively, while the average effluent concentrations of COD, LAS, and TP under stable operation states were 35.0 mg/L, 7.0 mg/L, and 4.4 mg/L, respectively. UMBAF played a major role in TP removal; the removal of COD in the combined UMBAF and MBAF process was consistent with the general formula C = C0 e -(ah + b) , while the kinetic model of LAS removal in the combined UMBAF and MBAF process could be expressed by L = L0 e-(mh + n) . The combined UMBAF-MBAF process provides a promising technology for the treatment of detergent wastewater. The kinetic model of LAS removal in the UMBAF and MBAF units is helpful for the prediction of the treatment efficiency of organic pollutants. PRACTITIONER POINTS: A novel UMBAF-MBAF process was developed treating detergent wastewater. The average removal rate of COD, LAS, and TP by the combined process was up to 91.4%, 88.5%, and 40%, respectively. Kinetic models for the UMBAF-MBAF process were investigated.


Assuntos
Ácidos Alcanossulfônicos/isolamento & purificação , Reatores Biológicos , Fosfatos/isolamento & purificação , Purificação da Água/métodos , Detergentes/isolamento & purificação , Cinética , Modelos Químicos , Águas Residuárias/química
13.
Int J Biol Macromol ; 124: 492-504, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30452994

RESUMO

The present investigation was carried out for the removal of phosphate and nitrate ions from aqueous solution using lanthanum incorporated chitosan membrane (La@CS) prepared by casting method. Systematic adsorption studies were performed by varying the influencing parameters like contact time, dosage, pH, interfering anions and temperature were optimized for the maximum phosphate and nitrate adsorption capacities. The adsorption equilibrium process was examined by Freundlich, Langmuir and Dubinin-Radushkevich isotherm models. The La@CS membrane showed an adsorption capacity of 76.6 and 62.6 mg/g for phosphate and nitrate ions respectively. Thermodynamic parameters such as ∆G°, ∆H° and ∆S° were calculated to understand the nature of adsorption. The synthesized La@CS membrane was characterized by FTIR, SEM, EDAX with mapping analysis, XRD, AFM, TGA-DSC and zero point charge analysis. The possible adsorption mechanism was found to be electrostatic attraction as well as by ion exchange between La@CS membrane and both anions like phosphate and nitrate. The experimental results clearly indicated that the prepared La@CS membrane could be utilized for the removal of phosphate and nitrate ions from aqueous solution.


Assuntos
Quitosana/química , Lantânio/química , Nitratos/isolamento & purificação , Fosfatos/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção , Humanos , Ligações de Hidrogênio , Concentração de Íons de Hidrogênio , Cinética , Membranas Artificiais , Eletricidade Estática , Temperatura Ambiente , Termodinâmica , Águas Residuárias/química
14.
Environ Sci Pollut Res Int ; 26(2): 1054-1060, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28185176

RESUMO

In this study, we focused on the rate of adsorption of phosphate on to the surface of magnetite in the presence of coexisting anions, organic matters and heavy metals. Magnetite particles were prepared using a co-precipitation method. Iron (II) sulfate heptahydrate and iron (III) chloride hexahydrate were mixed and then a sodium hydroxide solution was added drop-wise in the mixed iron solution. Coexisting anions were found to have no effect on the decrease in phosphate adsorption. However, phosphate adsorbed on to magnetite surface decreased with increasing total organic carbon (TOC) concentration of natural organic matter (NOM) such as citric, oxalic, and humic acid. The amount of phosphate adsorbed rapidly decreased with the increase of NOM concentration; therefore, it can be noted that NOM concentration considerably affects the adsorption of phosphate due to the negative charge exiting on the surface of NOMs. Glucose and ethanol, meanwhile, were found to have no effect on the phosphate adsorption. The amount of phosphate adsorbed did not change in the presence of heavy metals, namely, Pb and Cd, under acidic conditions. However, under alkaline conditions, the amount of phosphate adsorbed decreased with increasing concentrations of Pb and Cd. In the case of coexisting As(III), the amount of phosphate adsorbed decreased at all pH levels with increasing As(III) concentrations.


Assuntos
Óxido Ferroso-Férrico/química , Fosfatos/química , Água/química , Adsorção , Carbono/química , Precipitação Química , Concentração de Íons de Hidrogênio , Metais Pesados/química , Fosfatos/isolamento & purificação , Eliminação de Resíduos Líquidos/métodos
15.
Environ Geochem Health ; 41(4): 1767-1776, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28550602

RESUMO

The recovery of phosphate from human urine has been considered as one of the most attractive benefits of urine source separation because P is an essential but limited macronutrient. This study investigated the approach to modify wood waste biochar via metal oxides aiming to recover phosphate from human urine to produce a value-added biochar. Results showed the phosphate removal ability was enhanced for the modified biochar pre-treated in modification solutions of MgCl2, AlCl3, CaCl2 and FeCl3, respectively, while natural biochar released phosphate to urine. Among the tested biochar, Mg-biochar presented the best capacity for phosphate removal from the hydrolyzed urine, reaching 118 mgP g-1 at a MgCl2 concentration of 2.3 M. However, higher MgCl2 concentration would not further increase the adsorption capacity. Fitting of the adsorption kinetics and isotherms indicated that the phosphate removal process was probably controlled by multiple mechanisms. Both the experimental and fitting results confirmed that the content of Mg oxides was the key factor determining the adsorption rate and capacity of phosphate on Mg-biochar. pH ranges of 7-9 and the ammonium concentration higher than 108 mgN L-1 enhanced the phosphate adsorption capacity. As such, the Mg-biochar was more favored for the treatment of hydrolyzed urine rather than fresh urine with acidic pH and lower concentration of ammonium. Further calculations were carried out using the Langmuir model to evaluate the removal of phosphate and the product. Results indicate that it is an effective technique to use Mg-biochar for phosphate removal from hydrolyzed urine and it yields phosphate-enriched biochar products.


Assuntos
Carvão Vegetal/química , Óxido de Magnésio/química , Fosfatos/isolamento & purificação , Urina/química , Madeira/química , Adsorção , Humanos , Concentração de Íons de Hidrogênio , Hidrólise , Cinética , Metais/química , Modelos Teóricos , Óxidos/química , Fosfatos/química , Resíduos
16.
N Biotechnol ; 49: 43-47, 2019 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-30098415

RESUMO

This communication elaborates on the use of seashell powder (SP) for the removal of phosphate from lactic acid-containing fermentation broth. Despite extensive past research regarding the application of SP for phosphate removal from wastewater, no information is available for solutions containing various organic compounds. In order to fill this knowledge gap, tests were performed with pure phosphate solution (PPS) and PPS containing 0.83 M of three alcohols, ethanol, propanol or 1,2-propanediol, or 0.83 M of three organic acids, acetic, propionic or lactic acid. Furthermore, a real fermentation broth (RFB) obtained from the fermentative production of lactic acid from food waste was tested. Using 4.8 g SP, more than 95% of phosphate, present at an initial concentration of 50 mg L-1, could be removed from PPS and PPS containing alcohols after 120 min. The presence of organic acids reduced the removal capacity of SP and only 55%-73% of the phosphate initially present was removed. The presence of lactic acid also substantially affected the removal of phosphate from RFB when 132 mg L-1 phosphate was initially present: after 120 min, only 28.6 mg L-1 of phosphate had been removed. The results indicate the use of SP for phosphate removal from fermentation broth, contributing to multi-component utilization of fermentation broth. However, the effects of respective fermentation products on removal capacity should first be tested.


Assuntos
Exoesqueleto/química , Fermentação , Fosfatos/isolamento & purificação , Animais , Mytilus/química , Pós , Soluções
17.
J Colloid Interface Sci ; 533: 692-699, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30196113

RESUMO

Bimetallic oxides nanocomposites always exhibited the better phosphate capacities than those monometallic oxides samples. Herein, the high carbohydrate-content biomaterials, shaddock peels (SP), were used as the bio-host for supporting the bimetallic oxides, zirconium (Zr) and lanthanum (La) hydroxides, forming the SP-Zr-La composites. Phosphate adsorption properties as well as stability of the novel composites were evaluated. The SP-Zr-La composites indicated that some rod-like or amorphous nanoparticles with sizes of 20-150 nm were anchored inside the SP, which exerted more available interface interactions toward the adsorbed ions. The Zr-La species were pH-sensitive and adsorption capacity of phosphate by SP-Zr-La was increased with the rise in temperature. As the molar ratio of accompanying ions/phosphate was increased from 0 to 10 times, the SP-Zr-La was observed with the adsorption loss of 27.2-36.7%. Whereas the adsorption loss of cationic SP (grafted with quaternary ammonium groups) was calculated up to 86.2-91.6%; this indicated the more feasibility of SP-Zr-La in real applications. In addition, the stability of impregnated Zr and La species in SP-Zr-La was greatly improved by the bio-carrier through the "shielding effect" in a low HA surrounding.


Assuntos
Materiais Biocompatíveis/química , Celulose/química , Hidróxidos/química , Lantânio/química , Fosfatos/isolamento & purificação , Zircônio/química , Tamanho da Partícula , Fosfatos/química , Propriedades de Superfície
18.
Environ Sci Pollut Res Int ; 25(34): 34788-34792, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30324363

RESUMO

Porous magnesium oxide (MgO) films on carbon fiber paper (CF) have been successfully fabricated in a hydrothermal route at different calcination temperatures. The CF@MgO samples (CF@MgO-300, -400, and -500) show different morphologies with the increasing surface area from 3 for CF to 27 m2 g-1 for CF@MgO-400. Among the four investigated samples, the CF@MgO-400 exhibits the highest phosphate removal ability (~ 1230 mg g-1) with promising applications for the large-scale utilization at low cost.


Assuntos
Fibra de Carbono/química , Óxido de Magnésio/química , Fosfatos/isolamento & purificação , Adsorção , Ânions/isolamento & purificação , Precipitação Química , Poluentes Ambientais/isolamento & purificação , Metenamina/química , Papel , Porosidade , Temperatura Ambiente , Difração de Raios X
19.
J Environ Manage ; 225: 75-83, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30071368

RESUMO

Different biochars produced by the impregnation of Mg, Ca, Al, Cu, and Fe were compared for the phosphate (P) uptake capacity and the effect on solution pH. Among them, Ca- and Mg-rich biochars demonstrate better sorption ability to P and have less effect on pH change. The optimum conditions of the pyrolysis processes were determined using response surface methodology. Comparison of the P removal efficiency of these two biochars under optimum conditions imply the superior adsorption capability of Ca-rich biochar. According to XRD analysis, calcite is the dominant mineral on the biochar surface, indicating the potential of Ca-rich biochar for P removal by adsorption and precipitation. Predictive second-order kinetic and linear Langmuir isotherm models could adequately interpret the P sorption process for optimized Ca-rich biochar. The maximum P sorption capacity of Ca-rich biochar of 153.85 mg/g is superior to other adsorbents reported in literature.


Assuntos
Carvão Vegetal , Fosfatos/química , Poluentes Químicos da Água/química , Adsorção , Cátions , Fosfatos/isolamento & purificação , Esgotos , Poluentes Químicos da Água/isolamento & purificação
20.
Saudi J Kidney Dis Transpl ; 29(4): 872-878, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30152424

RESUMO

The inadequacy of dialysis and hyperphosphatemia are both associated with morbidity and mortality in chronic hemodialysis (HD) patients. Blood flow rate (BFR) during HD is one of the important determinants of increasing dialysis dose. The aim of this study was to determine the effect of increasing BFR on dialysis dose and phosphate removal. Forty-four patients were included in a cross-sectional study. Each patient received six consecutive dialysis sessions as follows: three consecutive sessions with a BFR of 250 mL/min, followed by three others with BFR of 350 mL/min without changing the other dialysis parameters. Patients' body weight was recorded, and blood samples (serum urea and phosphate) were collected before and after each dialysis session. For assessing the efficacy of dialysis, urea reduction ratio (URR), Kt/VDiascan (Kt by Diascan and V by Watson), Kt/V Daugirdas (Daugirdas 2nd generation), equilibrated Kt/V, and phosphate reduction rate (PRR) were used. The increase of BFR by 100 mL/min resulted in a significant increase of URR, Kt/V Diascan, Kt/VDaugirdas, equilibrated Kt/V, and PRR: URR; 75.41 ± 5.60; 83.51 ± 6.12; P <0.001), (Kt/VDiascan; 1.28 ± 0.25; 1.55 ± 0.15; P <0.001), (Kt/VDaugirdas; 1.55 ± 0.26; 2.10 ± 0.61; P = 0.001), equilibrated Kt/V; 1.40 ± 0.19; 1.91 ± 0.52; P = 0.001), and (PRR; 50.32 ± 12.22; 63.66 ± 13.10; P = 0.010). Adequate dialysis, defined by single-pool Kt/V ≥1.4, was achieved using two different BFRs: 250 and 350 mL/min, respectively, in 73% and 100% of the cases. Increasing the BFR by 40% is effective in increasing dialysis dose and phosphate reduction rate during high-flux HD. The future prospective studies are needed to evaluate the impact of increasing BFR on phosphate removal using the total amount of phosphate removed, and also evaluate the cardiovascular outcome of phosphate reduction and dialysis improvement.


Assuntos
Falência Renal Crônica , Fosfatos , Diálise Renal , Adulto , Idoso , Estudos Transversais , Feminino , Hemodinâmica , Humanos , Hiperfosfatemia/prevenção & controle , Falência Renal Crônica/complicações , Falência Renal Crônica/epidemiologia , Falência Renal Crônica/terapia , Masculino , Pessoa de Meia-Idade , Fosfatos/sangue , Fosfatos/isolamento & purificação , Diálise Renal/métodos , Diálise Renal/estatística & dados numéricos , Ureia/sangue , Ureia/isolamento & purificação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA