Degradation behavior of 17αup-ethinylestradiol by ozonation in the synthetic secondary effluent

Endocrine disrupting chemicals (EDCs) in the secondary effluent discharged from wastewater treatment plants (WWTPs) are of great concern in the process of water reuse. Ozonation has been reported as a powerful oxidation technology to eliminate micropollutants in water treatment. Due to the complexity of the wastewater matrix, orthogonal experiments and single factor experiments were conducted to study the influence of operational parameters on the degradation of 17αup-ethinylestradiol (EE2) in the synthetic secondary effluent. The results of the orthogonal experiments indicated that the initial ozone and natural organic matter (NOM) concentration significantly affected EE2 degradation efficiency, which was further validated by the single factor confirmation experiments. EE2 was shown to be effectively degraded by ozonation in the conditions of low pH (6), NOM (10 mg/L), carbonate (50 mg/L), but high suspended solid (20 mg/L) and initial ozone concentration (9 mg/L). The study firstly revealed that the lower pH resulted in higher degradation of EE2 in the synthetic secondary effluent, which differed from EDCs ozonation behavior in pure water. EE2 degradation by ozone molecule instead of hydroxyl radical was proposed to play a key role in the degradation of EDCs by ozonation in the secondary effluent. The ratio between O₃ and TOC was identified as an appropriate index to assess the degradation of EE2 by ozonation in the synthetic secondary effluent.     

Cadmium sorption by sodium and thiourea-modified zeolite-rich tuffs

In the present investigation, two zeolite-rich tuffs from Guaymas and El Cajon(State of Sonora), which were conditioned with a sodium chloride solution and subsequently modified with a thiourea solution, were chosen to evaluate the removal of Cd from aqueous systems. The zeolitic materials were characterized by scanning electron microscopy and X-ray diffraction. The surface area was also determined. The experiments were performed in a batch system, and the influences of p H, contact time between phases, and the concentration of Cd in the solution on the adsorption by sodium or thiourea-modified zeolite-rich tuff were investigated. It was found that the efficiency of Cd ion removal from aqueous solutions is influenced by the p H of the aqueous systems. The Cd adsorption kinetic data were well fitted to a pseudo-second-order model in all cases. The Langmuir and Langmuir–Freundlich isotherms adequately described the Cd sorption behavior by the zeolite from El Cajon pretreated with Na Cl and the zeolite from Guaymas modified with thiourea, respectively.     

Adsorption and biodegradation of three selected endocrine disrupting chemicals in river-based artificial groundwater recharge with reclaimed municipal wastewater

Endocrine disrupting chemical(EDC) pollution in river-based artificial groundwater recharge using reclaimed municipal wastewater poses a potential threat to groundwater-based drinking water supplies in Beijing, China. Lab-scale leaching column experiments simulating recharge were conducted to study the adsorption, biodegradation, and transport characteristics of three selected EDCs: 17β-estradiol(E2), 17α-ethinylestradiol(EE2) and bisphenol A(BPA). The three recharge columns were operated under the conditions of continual sterilization recharge(CSR), continual recharge(CR), and wetting and drying alternative recharge(WDAR). The results showed that the attenuation effect of the EDCs was in the order of WDAR CR CSR system and E2 EE2 BPA, which followed first-order kinetics. The EDC attenuation rate constants were 0.0783, 0.0505, and 0.0479 m-1 for E2, EE2 and BPA in the CR system, respectively. The removal rates of E2, EE2, and BPA in the CR system were 98%, 96% and 92%, which mainly depended on biodegradation and were affected by water temperature.In the CR system, the concentrations of BPA, EE2, and E2 in soil were 4, 6 and 10 times higher than in the WDAR system, respectively. According to the DGGE fingerprints, the bacterial community in the bottom layer was more diverse than in the upper layer, which was related to the EDC concentrations in the water-soil system. The dominant group was found to be proteobacteria, including Betaproteobacteria and Alphaproteobacteria, suggesting that these microbes might play an important role in EDC degradation.     

Kappaphycus alvarezii waste biomass: A potential biosorbent for chromium ions removal

The Cr(III) sorption experiments onto Kappaphycus alvarezii waste biomass were conducted at different pH values (2–6) under the conditions of initial metal concentration of 10–50 mg/L and the chemical compositions of Cr-Cu and Cr-Cd. The Cr(III) sorption capacities were slightly dependent on pH, and the maximum sorption capacity was 0.86 mg/g at pH 3. The sorption capacities increased with increase in the initial metal concentration, whereas it was suppressed by the presence of Cu(II) and Cd(III) in the solution. The Cr(III) sorption equilibrium was evaluated using Langmuir, Freundlich and BET isotherms. The sorption mechanisms were characterised using scanning electron microscopy and Fourier transform infrared spectroscopy. The main mechanisms were ion exchange coupled with a complexation mechanism. Kappaphycus alvarezii waste biomass represents a potential for Cr(III) ion removal from aqueous solution.     

Effect of background electrolytes on the adsorption of nitroaromatic compounds onto bentonite

To further elucidate interaction of nitroaromatic compounds with mineral surface, the sorption of m-dinitrobenzene (m-DNB) and nitrobenzene to original bentonite in aqueous solution containing di erent electrolytes (i.e., KCl, NH4Cl, CaCl2 and Tetramethylammonium bromide (TMAB)) was studied. The sorption of m-DNB was greatly enhanced with the presence of KCl and NH4Cl, while little influence was observed with CaCl2 and TMAB, following the order of KCl > NH4Cl TMAB, CaCl2, or DI water. For nitrobenzene, sorption enhancement only occurred at high nitrobenzene concentrations in the presence of KCl, and the solute equilibrium concentration at inflexion point was lowered with increasing KCl concentration. These sorption enhancements were significantly promoted with the increase of electrolyte concentration. The salting-out e ect is insu cient to account for the sorption enhancement by original bentonite with increasing KCl or NH4Cl concentration. X-ray di raction patterns of bentonite suspensions indicated that the sorption enhancement of m-DNB was attributed to the intercalation of K+ or NH4 + into bentonite interlayer and then dehydration with m-DNB to form inner-sphere complexes, which caused previously expanded bentonite interlayers to collapse in aqueous suspension, thus further enhanced the interaction of phenyl with siloxane surface. In comparison, the sorption enhancement of NB is attributed to the formation of outer-sphere complexes with K+ at high solute-loadings (> 200–400 mg/kg). The sorption of m-DNB to initially modified TMA+-bentonite and K+-bentonite was almost the same as respective sorption to original bentonite in solution containing TMA+ and K+.     

Equilibrium and kinetics of copper(Ⅱ) biosorption by Myriophyllum spicatum L.

The potential use of Myriophyllum spicatum L. biomass as a biosorbent for the removal of copper（ Ⅱ ） from aqueous solution was investigated in laboratory condition. The sorption experiments were undertaken to obtain copper（ Ⅱ ） biosorption properties of M. spicatum L., i.e. equilibrium time, the maximum capacity, and rate constants. Copper（ Ⅱ ） biosorption was fast and equilibrium was attained within 35 min at initial copper（ Ⅱ ） concentration of 6 mg/L. Different isotherm models including the Langmuir, Freundlich, Temkin and Redlich-Peterson model, were used to investigate the sorption capacity and isotherm. These models showed an excellent match with the experimental data except for the Freundlich model. According to the Langmuir coefficients, the maximum sorption capacity of copper onto M. spicatum L. was 10.80 mg/g. The kinetics of copper（ Ⅱ ） sorption was also analysed and rate constants were derived. It was found that the overall sorption process was best described by the pseudo second-order equation, and that intraparticle diffusion was not the rate determining step. The results of this study showed that M. spicatum L. can be considered as useful vehicles for the removal and recovery of copper（ Ⅱ ） from aqueous solutions.     

Photodegradation of Norfloxacin in aqueous solution containing algae

Photodegradation of Norfloxacin in aqueous solution containing algae under a medium pressure mercury lamp (15 W, λ_max = 365 nm) was investigated. Results indicated that the photodegradation of Norfloxacin could be induced by the algae in the heterogeneous algaewater systems. The photodegradation rate of Norfloxacin increased with increasing algae concentration, and was greatly influenced by the temperature and pH of solution. Meanwhile, the cooperation action of algae and Fe(III), and the ultrasound were beneficial to photodegradation of Norfloxacin. The degradation kinetics of Norfloxacin was found to follow the pseudo zero-order reaction in the suspension of algae. In addition, we discussed the photodegradation mechanism of Norfloxacin in the suspension of algae. This work will be helpful for understanding the photochemical degradation of antibiotics in aqueous environment in the presence of algae, for providing a new method to deal with antibiotics pollution.     

Removal of phenol by activated carbons prepared from palm oil mill effluent sludge

The study was attempted to produce activated carbons from palm oil mill effluent （POME） sludge. The adsorption capacity of the activated carbons produced was evaluated in aqueous solution of phenol. Two types of activation were followed, namely, thermal activation at 300, 500 and 800%, and physical activation at 150% （boiling treatment）. A control （raw POME sludge） was used to compare the adsorption capacity of the activated carbons produced. The results indicated that the activation temperature of 800℃ showed maximum absorption capacity by the activated carbon （POME 800） in aqueous solution of phenol. Batch adsorption studies showed an equilibrium time of 6 h for the activated carbon of POME 800. It was observed that the adsorption capacity was higher at lower values ofpH （2--3） and higher value of initial concentration of phenol （200--300 mg/L）, The equilibrium data were fitted by the Langmuir and Freundlich adsorption isotherms. The adsorption of phenol onto the activated carbon POME 800 was studied in terms of pseudo-first and second order kinetics to predict the rate constant and equilibrium capacity with the effect of initial phenol concentrations. The rate of adsorption was found to be better correlation for the pseudo-second order kinetics compared to the first order kinetics.     

Photocatalytic degradation of 4-tert-octylphenol in a spiral photoreactor system

A spiral photoreactor system (SPS) was developed for the degradation of 4-tert-octylphenol (4-t-OP) in aqueous phase. 4-t-OP was previously considered as a endocrine disrupting compound frequently present in water. The direct photodegradation reaction caused by the SPS was found to accord with the characteristic of apparent first-order reaction with reaction rate constantk= 4.8 × 10^-2 min^-1. However, the direct photodegradation reaction could not make the 4-t-OP mineralized. The photodegradation efficiency increased from 88% to 91.2% in 45 min irradiation period after the internal surface of SPS was sintered with TiO₂ thin film as catalyst. Catalyst concentration, number of catalyst coating layers and initial concentration of 4-t-OP were proven to be the factors affecting the photocatalytic degradation performance of the SPS on aqueous 4-t-OP. The degradation mechanism was investigated and the byproducts were analyzed using total organic carbon analyzer (TOC) and LC-MS. The possible chemical structures of the products were suggested. SPS with single layer of TiO₂ prepared by sintering 13.6% of TiO₂ precursor was proven to be more efficient than most of previous systems for removal of 4-t-OP from aqueous phase. 28.3% of the 4-t-OP was mineralized in 45 min according to the decreased amount of TOC value.     

Toxicity of the xenoestrogen nonylphenol and its biodegradation by the alga Cyclotella caspia

Alkylphenols (APs), the breakdown products of alkylphenol polyethoxylates that are widely used as surfactants, have been proven to exert estrogenic effects. With industrial development, higher concentrations of APs are discharged into aquatic environments. Nonylphenol (NP), the most noxious AP, is included in the blacklist of several countries. The toxicity of NP to the alga Cyclotella caspia and the biodegradation of NP by C. caspia were studied in the laboratory. The median effective concentration at 96 hr (96 hr EC50 ) of NP for C. caspia was found to be 0.18 mg/L. Five toxicity and three degradation indices were selected for toxicity and biodegradation experiments, respectively, in five or three concentrations of NP set by the 96 hr EC50 of NP. The algal growth rate and chlorophyll a contents decreased as NP concentration increased. The main manifestations of morphological deformity of the cells included volume expansion and the presence of cytoplasmic inclusions (lipid droplets). The abnormality rate of the cells increased with NP concentration and time, and was 100% at 0.22 and 0.26 mg/L of NP after 192 hr of culture. Superoxide dismutase activity initially increased and then declined at a higher NP toxicity of greater than 0.18 mg/L. After 192 hr of culture, the biodegradation rates of NP by C. caspia with initial concentrations of 0.14, 0.18, and 0.22 mg/L were 37.7%, 31.7%, and 6.5%, respectively. The kinetic equation of C. caspia biodegradation on NP was correlated with algal growth rate and initial NP concentration.     

Activated carbons derived from oil palm empty-fruit bunches： Application to environmental problems

Activated carbons derived from oil palm empty fruit bunches （EFB） were investigated to find the suitability of its application for removal of phenol in aqueous solution through adsorption process, Two types of activation namely; thermal activation at 300, 500 and 800℃and physical activation at 150℃ （boiling treatment） were used for the production of the activated carbons. A control （untreated EFB） was used to compare the adsorption capacity of the activated carbons produced from these processes. The results indicated that the activated carbon derived at the temperature of 800℃ showed maximum absorption capacity in the aqueous solution of phenol. Batch adsorption studies showed an equilibrium time of 6 h for the activated carbon at 800℃. It was observed that the adsorption capacity was higher at lower values of pH （2-3） and higher value of initial concentration of phenol （200-300 mg/L）. The equilibrium data fitted better with the Freundlich adsorption isotherm compared to the Langmuir. Kinetic studies of phenol adsorption onto activated carbons were also studied to evaluate the adsorption rate. The estimated cost for production of activated carbon from EFB was shown in lower price （USD 0.50/kg of activated carbon） compared the activated carbon from other sources and processes.     

Adsorption of 17β-estradiol from aqueous solution by raw and direct/pre/post-KOH treated lotus seedpod biochar

Five biochars derived from lotus seedpod(LSP) were applied to examine and compare the adsorption capacity of 17β-estradiol(E2) from aqueous solution.The effect of KOH activation and the order of activation steps on material properties were discussed.The effect of contact time,initial concentration,p H,ionic strength and humic acid on E2 adsorption were investigated in a batch adsorption process.Experimental results demonstrated that the pseudo second-order model fitted the experimental data best and that adsorption equilibrium was reached within 20 hr.The efficiency of E2 removal increased with increasing E2 concentration and decreased with the increase of ionic strength.E2 adsorption on LSP-derived biochar(BCs) was influenced little by humic acid,and slightly affected by the solution p H when its value ranged from 4.0 to 9.0,but considerably affected at p H 10.0.Low environmental temperature is favorable for E2 adsorption.Chemisorption,π–π interactions,monolayer adsorption and electrostatic interaction are the possible adsorption mechanisms.Comparative studies indicated that KOH activation and the order of activation steps had significant impacts on the material.Post-treated biochar exhibited better adsorption capacity for E2 than direct treated,pretreated,and raw LSP biochar.Pyrolyzed biochar at higher temperature improved E2 removal.The excellent performance of BCs in removing E2 suggested that BCs have potential in E2 treatment and that the biochar directly treated by KOH would be a good choice for the treatment of E2 in aqueous solution,with its advantages of good efficiency and simple technology.     

Biosorption of cadmium(Ⅱ) and lead(Ⅱ) ions from aqueous solutions onto dried activated sludge

The removal of heavy-metal ions from aqueous solutions by using dried activated sludge has been investigated in batch systems. Effect of solution pH, initial metal ion concentration, and temperature were determined. The results of the kinetic studies showed that the uptake processes of the two metal ions（Cd（Ⅱ） and Pb（Ⅱ）） followed the pseudo-second-order rate expression. The equilibrium data fitted very well to both the Langmuir and Freundlich adsorption models. The FT-IR analysis showed that the main mechanism of Cd（Ⅱ） and Pb（Ⅱ） biosorption onto dried activated sludge was their binding with amide I group.     

Use of sub-micron sized resin particles for removal of endocrine disrupting compounds and pharmaceuticals from water and wastewater

Endocrine disrupting compounds(EDCs) and pharmaceuticals pose a challenge for water and wastewater treatment because they exist at very low concentrations in the presence of substances at much higher concentrations competing for adsorption sites.Sub-micron sized resin particles(approximately 300 nm in diameter)(SMR) were tested to evaluate their potential as a treatment for EDCs including:17-β estradiol(E2),17-α ethinylestradiol(EE2),estrone(E1),bisphenol A(BPA),and diethylstilbestrol(DES) as well as 12 pharmaceuticals.SMR were able to remove 98%of spiked E2,80%of EE2,87%of BPA,and up to 97%of DES from water.For a 0.5 ppm mixture of E2,EE2,E1,BPA and DES,the minimum removal was24%(E2) and the maximum was 49%(DES).They were also able to remove the pharmaceuticals from deionized water and wastewater.Overall,SMR are a promising advanced treatment for removal of both EDCs and pharmaceuticals.     

Sorption of a triazol derivative by soils: importance of surface acidity

The sorption of a triazol derivative,1-(4-chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl)penten-3-ol with a common name of s3307D,on fifteen soils and three H2O2-treated soils was investigated.The sorption isotherm for each untreated and treated soil was nonlinear,and was best fitted to Freundlich sorption equation.Soils containing hith amount of clay content or organic matter or both sorbed much higher amounts of the chemical than soils that had low contents of these soil constituents.H2O2-treated soils showed sonsiderable sorptive affinity for S3307D.It was concluded that both organic matter and mineral fraction in natural soils contributed to the sorption of the basic compound.Sorption by the H2O2 treated soils increased as suspension pH decreased,but all suspension pHs exceeded the pKa of the compound by more than two units.This implies that organic base protonation can occur on surfaces of soil components,and surface acidity (exchangeable acidity)is important in sorption process of the organic base rather than suspension pH.     

Quantifying hysteresis of atrazine desorption from a sandy loam soil

Batch experiments were carried out to investigate the effects of initial atrazine concentrations and consecutive desorption steps on the desorption characteristics of atrazine from a sandy loam soil.As initial atrazine concentration increased,the average percentage of atrazine desorption on the sandy loam soil ranged gradually from 23.1% to 38.5% after five consecutive desorption steps.The values of the Freundlich capacity parameter,kdes,derived from the initial concentration and time-dependent desorption isotherm were consistently higher than those associated with sorption.The opposite trend was observed only for the values of nonlinear parameter,ndes,from the initial concentration-dependent desorption isotherms.Atrazine hydrolysis to hydroxyatrazine and bound residue formation were mainly responsible for the observed hysteresis in its sorption and desorption isotherms.For the initial concentration-dependent desorption isotherms,as initial atrazine concentration increased,the values of hysteretic coefficients ω and λ decreased,and H values increased.However,the relationships between initial atrazine concentration and hysteretic coefficients were not pronounced for ω,H,or λ.For the time-dependent desorption isotherms,λ and H values increased as the atrazine desorption step proceeded.The correlation between hysteretic coefficient and desorption step was highly significant for λ (P 0.0001),but not for H.     

Evaluation of carbon-based nanosorbents synthesised by ethylene decomposition on stainless steel substrates as potential sequestrating materials for nickel ions in aqueous solution

The present work covers the preparation of carbon-based nanosorbents by ethylene decomposition on stainless steel mesh without the use of external catalyst for the treatment of water containing nickel ions (Ni²⁺). The reaction temperature was varied from 650 to 850℃, while reaction time and ethylene to nitrogen flow ratio were maintained at 30 min and 1:1 cm³/min, respectively. Results show that nanosorbents synthesised at a reaction temperature of 650℃ had the smallest average diameter (75 nm), largest BET surface area (68.95 m²/g) and least amount of impurity (0.98 wt.% Fe). A series of batch sorption tests were performed to evaluate the effects of initial pH, initial metal concentration and contact time on Ni²⁺ removal by the nanosorbents. The equilibrium data fitted well to Freundlich isotherm. The kinetic data were best correlated to a pseudo second-order model indicating that the process was of chemisorption type. Further analysis by the Boyd kinetic model revealed that boundary layer diffusion was the controlling step. This primary study suggests that the prepared material with Freundlich constants compared well with those in the literature, is a promising sorbent for the sequestration of Ni²⁺ in aqueous solutions.     

Distribution and seasonal variation of estrogenic endocrine disrupting compounds, N-nitrosodimethylamine, and N-nitrosodimethylamine formation potential in the Huangpu River, China

Detection of estrogenic endocrine disrupting compounds(EDCs) and N-nitrosodimethylamine(NDMA) in drinking water has led to rising concerns. There are, however, a paucity of studies on the distribution and seasonal variation of NDMA and NDMA formation potential(NDMA-FP) in natural waters, especially in China. For EDCs, limited studies have investigated the distribution and seasonal variation of estrone(E1), 17β-estradiol(E2), estriol(E3), 17α-ethinylestradiol(EE2), technical-nonylphenols(t-NP), and bisphenol A(BPA) in Shanghai. In this study, water samples were collected from 11 sampling sites along the Huangpu River in 2012. The distribution and seasonal variation of EDCs, NDMA, and NDMA-FP were investigated. The results showed that all of the 11 sampling sites were contaminated by the target compounds. Compared with E2 and EE2, higher E1 and E3 concentrations were usually detected in the Huangpu River. The values of 17β-estradiol equivalents(EEQ) suggest a high possibility of endocrine effects on exposed organisms in the Huangpu River. NDMA-FP and t-NP were the dominant contaminants among the eight target compounds. The detection rates of the target compounds and their concentrations were both higher in dry seasons than in wet seasons. Higher concentrations of target compounds were observed in urban sampling sites near drainage outlets, and also in suburban sampling sites where intensive livestock farming and farmlands were located.     

Effects of humic acid coatings on phenanthrene sorption to black carbon

Black carbon (BC) can strongly adsorb hydrophobic organic compounds (HOCs).The HOC sorption to coated BC could be attenuated in soil and sediment compared with that of the parent BC.To study the potential causes of the sorption attenuation,humic acid (HA) and BC were isolated.Phenanthrene (PHE) was selected as the representative of HOCs.BC was coated with the precipitated HA.The PHE sorption to the HA-coated BC was determined.The HA coatings on BC could result in the significant sorption attenuation of PHE to BC.The attenuation varied in different HA origin and was positively correlated to the aromaticity of HA.The attenuation could be explained by the direct competition between HA and PHE for the available sorption sites on BC and the reduction of the available sorption sites as a result of the pore blockage of BC caused by the HA coatings.Therefore,the HA coatings on BC was one potential cause of the attenuation of HOC sorption to BC in soil and sediment.     

Effect of dissolved organic matter on sorption and desorption of phenanthrene onto black carbon

Sorption and desorption of phenanthrene （PHE） onto black carbon （BC） extracted from sediments were studied in the presence of three types of dissolved organic matter （DOM）, including L-phenylalanine （L-PH）, peptone and citric acid. The nonlinearity of the sorption isotherms increased in the presence of DOM. The presence of L-PH reduced the sorption capacity and desorption hysteresis because of the solubilization of PHE in L-PH solution. Peptone at 50-500 mg/L also led to a decrease in sorption attributed to solubilization, although the sorbed peptone on the BC surface could slightly increase PHE sorption. Unlike L-PH and peptone, citric acid enhanced the sorption capacity and irreversibility of PHE on BC mainly due to the strong sorption of citric acid on the BC surface. Our results may help to understand the different impacts of DOM on the distribution and transport of PAH in the environment.