10 research outputs found
Removal of metronidazole from aqueous solution using activated carbon
Metronidazole antibiotic is a medication once discharged into the water after use, can react with living organisms and causing adverse effects to their lives. This kind of contaminant must be removed from wastewater and the technique adopted in this work is the liquid-solid adsorption method. The removal of metronidazole in aqueous solutions is carried out on powdered activated carbon. Different parameters such as solid/liquid ratio, temperature, pH, concentration, and contact time influencing this adsorption are examined. The Langmuir isotherm appears the most satisfactory is best suited for modeling the adsorption of metronidazole. In addition, the pH and the temperature do not seem to have any noticeable effect on the adsorption of metronidazole. The experimental results showed that metronidazole was removed at 64% for concentration of 50 mg/L for contact time of 20 min
Competitive adsorption of heavy metals on local landfill clay
AbstractThe aim of this study is to investigate the interaction of CrIII and CdII ions in solution with the local landfill clay of Jebel Chakir (Ghorbel-Abid et al., 2009) located in the northwest of Tunis (Tunisia, North Africa). The adsorption properties of natural clay and the Na-purified clay in a chromium and cadmium rich aqueous solution have been studied by batch technique. The amount of adsorbed heavy metals ions, Qe, was determined for the adsorption systems as a function of the contact time, the pH, and the metal ion concentration. The results show that the uptake of CrIII by the purified clay is very fast. The quantity removed from the solution reached a maximum value 15min after mixing, for the purified clay, and 1h for the natural clay, although the latter removes greater quantities of CrIII ions compared to the Na-purified clay. However, the uptake of CdII reached its maximum value approximately 2h after mixing, for the purified clay, and 3.5h for the natural clay, although the removed quantities of CdII ions are comparable in both the Na-purified and natural clay.The experimental data points have been fitted to the Langmuir and Freundlich models. The competitive adsorption isotherms of CrIII and CdII ions in similar conditions have been studied by the batch technique. The amount of adsorbed ions, Qe was determined. The results show that the presence of CdII has an important effect on the uptake of CrIII
Nanoscale zero-valent iron functionalized Posidonia oceanica marine biomass for heavy metal removal from water
International audienceBecause of the excellent reducing capacity of nanoscale zero-valent iron (NZVI), it can be used as alternative materials for the removal of a variety of reducible water contaminants including toxic metals. The current paper reports the research results obtained for self-prepared biosorbent, Posidonia oceanica biomass, activated in alkaline medium and functionalized with NZVI particles. The structural characteristics, surface morphology, and binding properties of the resulting nanobiosorbent are presented. Batch comparative adsorption trials including adsorption kinetics and isothermals onto raw Posidonia, Posidonia-OH and Posidonia-OH-NZVI were investigated on three heavy metal ions: Cd(II), Pb(II), and Cu(II). The nanobiosorbent showed better properties, such as high reactivity and high uptake rate through the sorption process. The toxic metal removal has been monitored in terms of pseudo-first- and pseudo-second-order kinetics, and both Langmuir- and Freundlich-type isotherm models have been used to describe the sorption mechanism. The experimental data of all studied systems showed that the uptake kinetics follow the pseudo-second-order kinetic model and the equilibrium uptake can adopt the Langmuir-type isotherm model which assumes a monolayer coverage as the adsorption saturates and no further adsorption occurs. The thermodynamic results confirm that all sorption processes were feasible, spontaneous and thermodynamically favorable. Zeta potential data displayed that Cd(II), Pb(II), and Cu(II) tend to be reduced after exposure on the Posidonia-OH-NZVI surface. Furthermore, sorption competitions of the metals from binary and ternary systems were carried out onto Posidonia-OH-NZVI in order to gain further insight into the sorption efficiency of this material. Therefore, as a result, the proposed new nanobiosorbent could offer potential benefits in remediation of heavy metal-contaminated water as a green and environmentally friendly bionanocomposite
A Combination of Factorial Design, Off-line SPE and GCâMS Method for Quantifying Seven Endocrine Disrupting Compounds in Water
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Simultaneous detection of 13 endocrine disrupting chemicals in water by a combination of SPE-BSTFA derivatization and GC-MS in transboundary rivers (France-Belgium)
International audienceThe occurrence of endocrine-disrupting chemicals (EDCs) in the aquatic environment has brought increasing concern due to their potential adverse impacts on ecosystems and humans. These compounds are generally present in complex water matrices, such as surface waters at trace levels (ng Lâ1) making their analysis difficult. In this work, an analytical method for the simultaneous determination of 13 EDCs, including 5 steroid estrogens, 1 progestogen, 1 androgen, and 6 endocrine-disrupting phenols in water, was developed using solid phase extraction (SPE), derivatization, and gas chromatography-mass spectrometry (GC-MS). The method was validated by spiking the 13 EDCs to the interest matrix. The recovery was in the range of 52â71% with an average of 62%. The limits of quantification were 1 and 5â10 ng Lâ1 for phenolic compounds and hormones, respectively. The validated method was applied to assess the contamination level of the targeted EDCs in 15 sites collected from six rivers located at the cross-border area of Northern France and Belgium. The majority of the considered compounds were detected in the sampling sites and among them, bisphenol A (BPA) was found at the highest level which can be up to 286 ng Lâ1. However, NP was the most frequently detected, followed by BPA and PG
Removal of two anionic reactive textile dyes by adsorption into MgAl-layered double hydroxide in aqueous solutions
International audienceextile dyes pose a significant challenge for water pollution due to the poor degradability of their complex aromatic structures (e.g., RR-120 and RBB-150). In order to minimize the harmful effects of RR-120 and RBB-150, the capacity of MgAl-layered double hydroxide for removing of these contaminants was studied herein. Batch adsorption experiments were conducted to investigate the effect of various operating parameters, such as solution pH, contact time, dye concentration, and temperature in order to provide optimal conditions for removal. Structural and morphological analyses were used to highlight the assembly and/or interaction LDH-dye. The state of equilibrium of RR-120 and RBB-150 adsorption was pH- and temperature-dependent and followed the pseudo-second-order rate model. Also, the equilibrium adsorption data of both dyes were found to adopt the Langmuir type isotherm model, which assumes a monolayer arrangement in LDH-dye. Furthermore, the effects of four major coexisting and competing mono- and divalent interlayer anions, such as NO3-, Cl-, CO32-, and SO42-, on the uptakes of RR-120 and RBB-150 were studied and the results showed that NO3- anions had insignificant effect on the uptakes of RR-120 and RBB-150 by MgAl. An equivalent study on the presence of both dyes in competitive trial adsorption/desorption from binary aqueous solution was investigated. And finally, the reuse operation of recovered material after dye adsorption was tested in up to 5 cycles of recyclability