Treatment of Agro-Food Wastewaters and Valuable Compounds Recovery by Column Sorption Runs

Olive oil extraction generates a large quantity of wastewater which is a strong pollutant due to its high organic load and phytotoxic. However, its content in antibacterial phenolic substances displays to be resistant to biological degradation. The discharge of olive mill wastewater (OMWW) is not allowed through the municipal sewage system and/or in a natural effluent. Unfortunately, the current technologies for the treatment of OMWW are expensive and complicated to be operated in a mill factory where the objective of this study. We have designed and implemented a process that permitted both the treatment of agro-food processing water and the recovering of compounds of market interest. The process was applied in the effluents of olive oil mill factories to recover polyphenols with a possible significant reduction of organic waste. The nanofiltration fraction obtained from a sequential treatment involved coagulation, photocatalysis, ultrafiltration and nanofiltration was performed to separate the most valuable compounds using column adsorption runs. Competitive adsorption and the selectivity were obtained for phenol and hydroxytyrosol onto macro-reticular aromatic polymer (FPX66) and macroporous polystyrene cross-linked with divinylbenzene (MN202), respectively. The investigations were followed by a single component of phenol or tyrosol, binary phenol and tyrosol and ternary components in NF concentrate of OMWW for valuable compounds recovery conducted in a fixed-bed adsorber of resins. During the intermediate stage of the column operation, adsorbed tyrosol molecules were replaced by the incoming phenol molecules due to the lower tyrosol affinity for FPX66 resin and the tyrosol concentration was higher than its feed concentration

Competitive adsorption, selectivity and separation of valuable hydroxytyrosol and toxic phenol from olive mill wastewater

Competitive adsorption and selectivity of toxic phenol and hydroxytyrosol were studied on the macroreticular aromatic polymer (FPX66) and the macroporous polystyrene cross linked with divinylbenzene (MN202). The adsorption equilibrium of phenol and hydroxytyrosol as well as other phenolic compounds in olive mill wastewater (OMW) was investigated taking into account the different affinities of these compounds towards the two above mentioned resins. The experimental results showed that the adsorption equilibrium of phenol on FPX66 can be well interpreted by the BET model, indicating a multilayer adsorption, whereas, the adsorption of hydroxytyrosol on MN202 at equilibrium is well fitted by the Sips model. At low FPX66 concentration, phenol exhibited much higher adsorption percentage than hydroxytyrosol, indicating a stronger interaction with the resin. The adsorption selectivity ratio of phenol/hydroxytyrosol was of about 3.215 at 5 g L−1 of FPX66. Thanks to the large affinity of hydroxytyrosol for the MN202 resin, its adsorption and recovery were higher than 90% on this resin. Thus, under suitable operating conditions, phenol was selectively separated on FPX66, while hydroxytyrosol was largely recovered from the OMW residual solution by adsorption on MN202

Free radicals quenching potential, protective properties against oxidative mediated ion toxicity and HPLC phenolic profile of a Cameroonian spice: Piper guineensis

Considerations on antioxidants derived from plants have continuously increased during this decade because of their beneficial effects on human health. In the present study we investigated the free radical scavenging properties of extracts from Piper guineense (P. guineense) and their inhibitory potentials against oxidative mediated ion toxicity. The free radical quenching properties of the extracts against [1,1-diphenyl-2-picrylhydrazyl (DPPH·−), 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS·−), hydroxyl radical (HO·−), nitric oxide (NO·−)] radical and their antioxidant potentials by FRAP and phosphomolybdenum were determined as well as their protective properties on liver enzymes. The phenolic profile was also investigated by HPLC. The results obtained, revealed that the extracts significantly inhibited the DPPH, NO, HO and ABTS radicals in a concentration depending manner. They also showed a significant ferrous ion chelating ability through FRAP and phosphomolybdenum antioxidant potential. Their polyphenol contents varied depending on the type of extracts and the solvent used. The hydroethanolic extracts (FFH) and the ethanolic extracts (FFE) of P. guineense leaves showed the higher level of phenolic compounds respectively of 21.62 ± 0.06 mg caffeic acid/g dried extract (CAE/g DE) and 19.01 ± 0.03 CAE/g DE. The HPLC phenolic compounds profile revealed a higher quantity of Eugenol, quercetin, rutin and catechin in the stem than in the leaves. The presence of these molecules could be responsible of the protective potentials of P. guineense extracts against lipid peroxidation and SOD, catalase and peroxidase. In conclusion, P. guineense extracts demonstrated significant antioxidant property and may be used as a prospective protector against metal related toxicity

In vitro antioxidant properties, free radicals scavenging activities of extracts and polyphenol composition of a non-timber forest product used as spice: Monodora myristica

BACKGROUND: Excessive production of free radicals causes direct damage to biological molecules such as DNA, proteins, lipids, carbohydrates leading to tumor development and progression. Natural antioxidant molecules from phytochemicals of plant origin may directly inhibit either their production or limit their propagation or destroy them to protect the system. In the present study, Monodora myristica a non-timber forest product consumed in Cameroon as spice was screened for its free radical scavenging properties, antioxidant and enzymes protective activities. Its phenolic compound profile was also realized by HPLC. RESULTS: This study demonstrated that M. myristica has scavenging properties against DPPH',OH',NO', and ABTS'radicals which vary in a dose depending manner. It also showed an antioxidant potential that was comparable with that of Butylated Hydroxytoluene (BHT) and vitamin C used as standard. The aqueous ethanol extract of M. myristica barks (AEH); showed a significantly higher content in polyphenolic compounds (21.44 ±0.24 mg caffeic acid/g dried extract) and flavonoid (5.69 ± 0.07 quercetin equivalent mg/g of dried weight) as compared to the other studied extracts. The HPLC analysis of the barks and leaves revealed the presence of several polyphenols. The acids (3,4-OH-benzoic, caffeic, gallic, O- and P- coumaric, syringic, vanillic), alcohols (tyrosol and OH-tyrosol), theobromine, quercetin, rutin, catechine and apigenin were the identified and quantified polyphenols. All the tested extracts demonstrated a high protective potential on the superoxide dismutase (SOD), catalase and peroxidase activities. CONCLUSION: Finally, the different extracts from M. myristica and specifically the aqueous ethanol extract reveal several properties such as higher free radical scavenging properties, significant antioxidant capacities and protective potential effects on liver enzymes

Electrochemical sensor based on green-synthesized iron oxide nanomaterial modified carbon paste electrode for Congo red electroanalysis and capacitance performance

In this study, a facile protocol was used to convert non-valuable orange peels (OP) waste into a new sensing iron oxide orange-peel nanomaterial (FeOP). The presence of iron oxide nanoparticles in the modified OP was confirmed by physicochemical characterisations including Fourier-transform infrared spectroscopy, X-ray diffractometry, thermogravimetry, and scanning electron microscopy-energy dispersive X-ray. FeOP was used to modify a carbon paste electrode (CPE/FeOP) which displayed a significant increase in specific capacitance of 2939 F.g−1, two folds higher than that obtained with CPE at 10 m.s−1 in NaCl. The electroanalysis of Congo red (CR) in aqueous solutions using CPE/FeOP displayed detection limits of 2.8 × 10−7 mol.L−1 and 8.2 × 10−7 mol.L−1 respectively in deionised and spring waters, in the linear range of 5 to 55 µM. CPE/FeOP electrochemical sensor is therefore suitable for the determination of Congo red in wastewater.</p