- Feasibility of using low-cost, byproduct materials as sorbents to remove heavy metals from aqueous solutions. [Journal Article]
- ETEnviron Technol 2018 Feb 22; :1-10
- This work investigates the sorption of heavy metals by low-cost, byproducts such as charcoal fines (CF), waste green sand, and rice husk ash, in order to examine the feasibility of their use as alter...
This work investigates the sorption of heavy metals by low-cost, byproducts such as charcoal fines (CF), waste green sand, and rice husk ash, in order to examine the feasibility of their use as alternative filter materials for metal-contaminated waters. The sorption of Cd, Cu, Pb, and Zn was investigated in batch experiments and sorption isotherms were constructed. The three byproducts showed high metal removal efficiencies (>95%, regardless of the metal concentration tested). The highest metal sorption distribution coefficients were obtained for CF, with maximum values within the 105-106 L kg-1range for all the target metals. The sorption isotherms were satisfactorily fitted using the Freundlich equation and a linear model, the latter only being valid for initial metal concentrations lower than 0.4 mmol L-1. Sorption reversibility was very low, with desorption yields lower than 2% and desorption distribution coefficients often higher than 106 L kg-1. The values of the sorption and desorption parameters indicated that the use of these materials, especially CF, could constitute a low-cost alternative for the remediation of contaminated waters.
- Effective adsorption of sulfamethoxazole, bisphenol A and methyl orange on nanoporous carbon derived from metal-organic frameworks. [Journal Article]
- JEJ Environ Sci (China) 2018; 63:250-259
- Nanoporous carbons (NPCs) derived from metal-organic frameworks (MOFs) are attracting increasing attention in many areas by virtue of their high specific surface area, large pore volume and unique po...
Nanoporous carbons (NPCs) derived from metal-organic frameworks (MOFs) are attracting increasing attention in many areas by virtue of their high specific surface area, large pore volume and unique porosity. The present work reports the preparation of an NPC with high surface area (1731m2/g) and pore volume (1.68cm3/g) by direct carbonization of MOF-5. We examined the adsorption of three typical contaminants from aqueous solutions, i.e., sulfamethoxazole (SMX), bisphenol A (BPA) and methyl orange (MO), by using the as-prepared NPC. The results demonstrated that NPC could adsorb the contaminants effectively, with adsorption capacity (qm) of 625mg/g (SMX), 757mg/g (BPA) and 872mg/g (MO), respectively. These values were approximately 1.0-3.2 times higher than those obtained for single-walled carbon nanotubes (SWCNTs) and commercial powder active carbon (PAC) under the same conditions. With its high surface area and unique meso/macropore structure, the enhanced adsorption of NPC most likely originates from the cooperative interaction of a pore-filling mechanism, electrostatic interaction, and hydrogen bonding. In particular, the pH value has a crucial impact on adsorption, suggesting the significant contribution of electrostatic interaction between NPC and the contaminants. This study provides a proof-of-concept demonstration of MOF-derived nanoporous carbons as effective adsorbents of contaminants for water treatment.
- A validated liquid chromatography-high resolution-tandem mass spectrometry method for the simultaneous quantitation of tryptophan, kynurenine, kynurenic acid, and quinolinic acid in human plasma. [Journal Article]
- EElectrophoresis 2018 Jan 12
- Tryptophan (TRP) catabolism via the kynurenine pathway is considered to represent a major link between inflammation and various diseases, including neurodegenerative disorders, depression, schizophre...
Tryptophan (TRP) catabolism via the kynurenine pathway is considered to represent a major link between inflammation and various diseases, including neurodegenerative disorders, depression, schizophrenia, multiple sclerosis, cardiovascular disease, and cancer. The kynurenine pathway and levels of TRP and its metabolites kynurenine (KYN), kynurenic acid (KYNA) and quinolinic acid (QUIN) are well regulated under physiological conditions but may be altered as part of the activated immune response. A simple, sensitive, and specific liquid chromatography-time of flight mass spectrometry method was developed for determining levels of the four compounds in human plasma samples. The workflow involves protein precipitation with acetonitrile, chromatographic separation on a Phenomenex Luna NH2 column by applying a linear 6 min gradient of 50-5% acetonitrile in aqueous ammonium acetate solution (5 mM, pH 9.5), and mass spectrometric detection with high-resolution tandem mass spectrometry. Charcoal-treated plasma served as surrogate matrix for external standard calibration. Stable-isotope-labeled analogues were used as internal standards. The calibration ranges were 0.5-50 μg/ml for TRP, 20-1000 ng/mL for KYN und QUIN, and 1-50 ng/mL for KYNA. Validation proved fitness of the developed workflow for the intended purpose. The established method was applied to the quantification of the four targets in 100 authentic plasma samples.
- Densitometry of the optically magnified dried residues representing carbon microparticles as a simple and affordable technique for determining their concentrations in aqueous suspensions. [Journal Article]
- MMicron 2018; 106:42-47
- In extracorporeal blood purification, such as hemoperfusion, activated carbon (activated charcoal) beads are commonly used as an adsorbent, but their judgment in terms of extent of microparticle rele...
In extracorporeal blood purification, such as hemoperfusion, activated carbon (activated charcoal) beads are commonly used as an adsorbent, but their judgment in terms of extent of microparticle release is of great importance since the microparticles may represent the risk of entering the bloodstream. To quantitatively assess the release of carbon microparticles (CMPs) in the samples of the aqueous perfusion medium, in which the beads have been perfused, the calibration procedure with different concentrations of CMPs is likely to be needed. For this purpose, carbon beads were mechanically crushed to a fine powder, whose microparticles (<10 μm) were then serially diluted in the aqueous medium within the wide range of concentrations (0.2-100 μg/ml). To test these concentrations of CMPs, the micro-aliquots of each dilution of suspended CMPs were dried on a surface of hydrophobic membrane and at the optical magnification of 20× the dry residues were than analyzed by measuring the sum of densities. This simple and affordable technique was shown to be considerably more sensitive than spectrophotometry of the aqueous suspensions of CMPs.
- Efficient removal of Hg2+in aqueous solution with fishbone charcoal as adsorbent. [Journal Article]
- ESEnviron Sci Pollut Res Int 2017 Dec 29
- The Hg2+removal performance of fishbone charcoal prepared from discarded fishbone has been investigated in this work. The XRD, FTIR, and BET results demonstrated that the main composition of fishbone...
The Hg2+removal performance of fishbone charcoal prepared from discarded fishbone has been investigated in this work. The XRD, FTIR, and BET results demonstrated that the main composition of fishbone charcoal was hydroxyapatite and the specific surface area was 117 m2/g. The adsorption experiments indicated that fishbone charcoal had an extremely high adsorption capacity for Hg2+(243.77 mg/g). The excellent Hg2+adsorption capacity might be ascribed to the ion exchange of Hg2+to the Ca2+in the structure of fishbone charcoal, complexation of Hg2+with ≡Ca(OH)2+on the surface of fishbone charcoal, as well as electrostatic interaction between electronegative fishbone charcoal surface and cation Hg2+. This work transformed kitchen garbage (i.e., fishbone) into an effective mercury adsorbent with considerable capacity, giving a perspective sight for the utilization of solid waste.
- Reverse Effect of Opuntia ficus-indica L. Juice and Seeds Aqueous Extract on Gastric Emptying and Small-Bowel Motility in Rat. [Journal Article]
- JFJ Food Sci 2018; 83(1):205-211
- This study was conducted to compare the effects of juice and seeds on gastric emptying, small-bowel motility and intestinal ion transport. Separate groups of rats were randomized to receive NaCl, inc...
This study was conducted to compare the effects of juice and seeds on gastric emptying, small-bowel motility and intestinal ion transport. Separate groups of rats were randomized to receive NaCl, increasing doses of juice (5, 10, and 20 mL/kg, b.w.) or seeds aqueous extract (100, 200, and 400 mg/kg, b.w.). Simultaneously, two other groups were received, the reference drugs; clonidine (1 mg/kg) and yohimbine (2 mg/kg). The charcoal meal was used as a suspension for gastrointestinal motility test. The purgative action of juice was confirmed using the loperamide (5 mg/kg, p.o.) induced constipation. To evaluate the antisecretory effect, we were used as a hypersecretion agent, the castor oil at the dose of 5 mL/kg. Compared to the control and standard groups, we were showed that the prickly pear has an opposite effect on small-bowel motility and gastric emptying. Indeed, the juice at various doses has a laxative effect of gastrointestinal transit in healthy and constipated-rats. However, the aqueous extract of the seeds leads to a reduction of motility in normal rats which gives it a remarkable antidiarrhoeal activity, a notable intestinal fluid accumulation decline and electrolyte concentrations reestablishment. Moreover, orally juice administered at different doses accelerated the stomach emptying time in contrast to the seeds aqueous extract. More importantly, a significant variation in the phytochemical constituents levels between juice and seeds was found. These findings confirm the reverse therapeutic effects of this fruit in the treatment of digestive disturbances such as difficulty stool evacuation and massive intestinal secretion, likewise, the gastric emptying process perturbation.
- Dual mechanisms of anti-muscarinic and Ca++antagonistic activities to validate the folkloric uses of Cyperus niveus Retz. as antispasmodic and antidiarrheal. [Journal Article]
- JEJ Ethnopharmacol 2018 Mar 01; 213:138-148
- CONCLUSIONS: This study shows the presence of antidiarrheal and spasmolytic activities in Cyperus niveus Retz. extract, mediated by dual blocking mechanisms of muscarinic receptors and Ca2+channels. The results further indicate the presence of anti-emetic activity in Cn. Cr, which may be because of its anti-muscarinic potential. This study provides the scientific bases to the traditional use of Cn. Cr in diarrhea and emesis.
- Antidiarrhoeic effect and dereplication of the aqueous extract of Annona crassiflora (Annonaceae). [Journal Article]
- NPNat Prod Res 2017 Nov 08; :1-5
- We investigated the antidiarrhoeic effect of the aqueous extract of Annona crassiflora leaves (AEAC). The AEAC decreased the diarrhoeic stools and enteropooling induced by castor oil, without alterin...
We investigated the antidiarrhoeic effect of the aqueous extract of Annona crassiflora leaves (AEAC). The AEAC decreased the diarrhoeic stools and enteropooling induced by castor oil, without altering total faecal output; moreover, the distance travelled by charcoal meal in the intestine was increased. Twenty-eight compounds were identified by LC-DAD-MS in the AEAC, including flavonoids, alkaloids and proanthocyanidins. In addition, two oligomeric series of condensed tannins of up to nine flavan-3-ol units were characterised by MALDI-MS. These data suggest that the antidiarrhoeic effect of the AEAC is related to its ability to inhibit intestinal secretion and/or to increase intestinal absorption. Moreover, the prokinetic effect of AEAC, together with its inhibitory effect on enteropooling induced by castor oil, explains why this extract decreased diarrhoeic faeces without altering the total faecal output. All these effects are in agreement with the pharmacological activity reported in the literature for many of the secondary metabolites identified.
- Pb(II) sorption from aqueous solution by novel biochar loaded with nano-particles. [Journal Article]
- CChemosphere 2018; 192:1-4
- Novel sorbent (HBC) is prepared by introducing nano-particles (Maghemite and EDTA functionalized layered double hydroxides) on biochar surface. FTIR, XRD, SEM and EDS are used to characterize the bio...
Novel sorbent (HBC) is prepared by introducing nano-particles (Maghemite and EDTA functionalized layered double hydroxides) on biochar surface. FTIR, XRD, SEM and EDS are used to characterize the biochar nanocomposites. Pb(II) sorption is highly dependent on solution pH. Sorption kinetics and isotherms indicate that Pb(II) sorption onto the sorbents follows pseudo-second order model and Langmuir isotherm. The maximum sorption capacity of Pb(II) onto HBC is up to146.84 mg g-1, higher than previously reported sorbents. The magnetic particles enable easy separation of HBC from aqueous solution by external magnetic fields. HBC can be used as effective sorbent for removal of heavy metals from wastewater.
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- Augmenting granular activated carbon with natural clay for multicomponent sorption of heavy metals from aqueous solutions. [Journal Article]
- WSWater Sci Technol 2017; 76(7-8):2213-2221
- Multicomponent adsorption of Cd, Cr, Cu, Pb and Zn onto date palm pits based granular activated carbon (GAC) augmented with highly active natural clay at different proportion was investigated. The ef...
Multicomponent adsorption of Cd, Cr, Cu, Pb and Zn onto date palm pits based granular activated carbon (GAC) augmented with highly active natural clay at different proportion was investigated. The effects of the initial pH and the adsorbents mixed ratio on the removal selectivity sequence of the metals evaluated. Batch adsorption experiments were undertaken at initial pH 2, 6 and 12. At initial pH 2, both the percent removal and the metals adsorptive capacity decreased with increasing GAC to clay ratio (from 0 to 1) with the percentage removal of Cd, Zn and Cr ions dropping from 68, 81, 100% to 43, 57 and 70%, respectively. At both pH 6 and 12, the percentage removals and adsorption capacities of all the heavy metal ions are higher than at pH 2. Selectivity sequences for pH 2, 6 and 12 followed the order Pb > Cr > Cu > Zn > Cd; Pb > Cr > Cu > Cd > Zn and Cd > Cr > Cu > Pb > Zn, respectively. The adsorption trends were analyzed in relation to point of zero charge and ξ-potential and the metals ions speciation at different pH. These results will help better understand the feasibility of augmenting GAC with natural clay minerals during fixed bed column test which is more beneficial for practical industrial applications.