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Papers by Mariangela Grassi

Research paper thumbnail of Removal of Emerging Contaminants from Water and Wastewater by Adsorption Process

SpringerBriefs in Molecular Science, 2012

Research paper thumbnail of Pretreatment of olive mill wastewater by chitosan coagulation and advanced oxidation processes

Separation and Purification Technology, 2008

In the present work the combined pre-treatment of actual olive mill wastewaters by coagulation wi... more In the present work the combined pre-treatment of actual olive mill wastewaters by coagulation with natural organic coagulant, such as chitosan, and the advanced oxidation processes, specifically photocatalysis (PC), Fenton (F) and photo-Fenton (PF), was investigated. The optimum removal of total suspended solids (TSSs, 81%) by chitosan coagulation was achieved at actual pH (4.3) for 400 mg L−1 coagulant dose. The maximum organic matter removals by F (85%) and PF (95%) processes were achieved after 2.0 and 1.0 h, respectively by using 15,000/1852 (w/w) ratio of H2O2/FeSO4. On the opposite, in PC experiments, after an initial decrease in the early minutes of the treatment, a subsequent increase versus irradiation time was observed for both UV absorbance at 280 nm and chemical oxygen demand (COD); probably a partial oxidation made some organics detectable only after treatment.

Research paper thumbnail of Pre-treatment of olive mill wastewater by chitosan coagulation and advanced oxidation processes

Separation and Purification Technology, 2008

In the present work the combined pre-treatment of actual olive mill wastewaters by coagulation wi... more In the present work the combined pre-treatment of actual olive mill wastewaters by coagulation with natural organic coagulant, such as chitosan, and the advanced oxidation processes, specifically photocatalysis (PC), Fenton (F) and photo-Fenton (PF), was investigated. The optimum removal of total suspended solids (TSSs, 81%) by chitosan coagulation was achieved at actual pH (4.3) for 400 mg L −1 coagulant dose. The maximum organic matter removals by F (85%) and PF (95%) processes were achieved after 2.0 and 1.0 h, respectively by using 15,000/1852 (w/w) ratio of H 2 O 2 /FeSO 4 . On the opposite, in PC experiments, after an initial decrease in the early minutes of the treatment, a subsequent increase versus irradiation time was observed for both UV absorbance at 280 nm and chemical oxygen demand (COD); probably a partial oxidation made some organics detectable only after treatment.

Research paper thumbnail of Endocrine disruptors compounds, pharmaceuticals and personal care products in urban wastewater: implications for agricultural reuse and their removal by adsorption process

Environmental Science and Pollution Research, 2013

In the last years, a lot of emerging contaminants, such as, endocrine disruptors compounds (EDCs)... more In the last years, a lot of emerging contaminants, such as, endocrine disruptors compounds (EDCs), pharmaceuticals, and personal care products (PPCPs) have been detected in wastewater. Because of their toxicity and possible adverse effects on the environment and humans, their release from urban wastewater treatment plants (UWWTPs) effluents should be minimized, particularly when a wastewater reuse for crops irrigation is expected. Many processes have been investigated for advanced treatment of UWWTP effluents as well as for emerging contaminant degradation; among these, adsorption process was successfully used to remove EDCs and PPCPs from wastewater. This article shortly reviews EDCs and PPCPs removal from UWWTP effluents by adsorption process using conventional and non-conventional adsorbents. The fate of EDCs and PPCPs in UWWTPs and the implications for agricultural wastewater reuse has been addressed too. In spite of the adsorption process looking to be a valuable alternative to other advanced technologies for the removal of emerging contaminants from wastewater, some gaps still remain to evaluate the actual feasibility at full scale. However, according to a few studies available in scientific literature on the use of both powdered activated carbon and granular activated carbon at full scale, adsorption process by activated carbon is a promising, potentially effective, and economically feasible solution for producing safe wastewater for agricultural reuse.

Research paper thumbnail of Advanced oxidation of catechol: A comparison among photocatalysis, Fenton and photo-Fenton processes

Desalination, 2009

The aim of this work was to compare the behaviour of Fenton, photo-Fenton and photocatalysis proc... more The aim of this work was to compare the behaviour of Fenton, photo-Fenton and photocatalysis processes to treat catechol solutions which are pollutants occurring in wastewaters from many industries. The effect of different process parameters, such as initial catechol concentration, H 2 O 2 /FeSO 4 ratio in Fenton and photo-Fenton oxidation, TiO 2 loadings in photocatalysis and irradiation times has been studied. Fenton and photo-Fenton (H 2 O 2 /FeSO 4 = 600/500 (w/w) and 30 min reaction time) processes allowed us to achieve a high efficiency in the mineralization of catechol (COD removals up to 83% and 96% respectively), and removal of aromaticity (UV 280 ) (up to 93% and 98% respectively), for an initial catechol concentration of 110 mg/l. On the opposite, photocatalysis was not effective in the removal of higher catechol concentrations (110 and 200 mg/l), whereas a significant removal of aromaticity versus time was observed for 50 mg/l. Gas chromatography-mass spectrometry analysis, performed under selected treatment conditions, showed that total removal of catechol can occur after Fenton (2000/500 w/w; 30 min), photo-Fenton (600/500 w/w; 30 min), and photocatalysis (3 g TiO 2 /l; 240 min) treatments.

Research paper thumbnail of Advanced treatment of urban wastewater by sand filtration and graphene adsorption for wastewater reuse: Effect on a mixture of pharmaceuticals and toxicity

Pharmaceuticals removal from urban wastewater by coupling conventional sand filtration with graph... more Pharmaceuticals removal from urban wastewater by coupling conventional sand filtration with graphene adsorption reactor (GAR) was investigated. During GAR regime phase, the percentage removal of the four investigated pharmaceuticals, (namely caffeine, carbamazepine, ibuprofen and diclofenac) was higher than 95% (98.2, 97.0, 95.5 and 97.0%, respectively). In spite of the high initial concentrations of the target pharmaceuticals (10 mg/L each) and 4 months of experimentation (62 days of adsorption treatment), typical breakthrough adsorption curves were not observed. Graphene adsorption treatment effectively decreased toxicity to Daphnia magna (0–50% immobilization), but only a slight improvement in germination index (phyto-toxicity tests) was observed after GAR treatment. Finally, graphene performances were compared with conventional (granular activated carbon) adsorption process, and the best performance in the removal of pharmaceutical mixture was quite poor (62% in terms of UV absorbance) compared to GAR (96%).

Research paper thumbnail of Removal of Emerging Contaminants from Water and Wastewater by Adsorption Process

SpringerBriefs in Molecular Science, 2012

Research paper thumbnail of Pretreatment of olive mill wastewater by chitosan coagulation and advanced oxidation processes

Separation and Purification Technology, 2008

In the present work the combined pre-treatment of actual olive mill wastewaters by coagulation wi... more In the present work the combined pre-treatment of actual olive mill wastewaters by coagulation with natural organic coagulant, such as chitosan, and the advanced oxidation processes, specifically photocatalysis (PC), Fenton (F) and photo-Fenton (PF), was investigated. The optimum removal of total suspended solids (TSSs, 81%) by chitosan coagulation was achieved at actual pH (4.3) for 400 mg L−1 coagulant dose. The maximum organic matter removals by F (85%) and PF (95%) processes were achieved after 2.0 and 1.0 h, respectively by using 15,000/1852 (w/w) ratio of H2O2/FeSO4. On the opposite, in PC experiments, after an initial decrease in the early minutes of the treatment, a subsequent increase versus irradiation time was observed for both UV absorbance at 280 nm and chemical oxygen demand (COD); probably a partial oxidation made some organics detectable only after treatment.

Research paper thumbnail of Pre-treatment of olive mill wastewater by chitosan coagulation and advanced oxidation processes

Separation and Purification Technology, 2008

In the present work the combined pre-treatment of actual olive mill wastewaters by coagulation wi... more In the present work the combined pre-treatment of actual olive mill wastewaters by coagulation with natural organic coagulant, such as chitosan, and the advanced oxidation processes, specifically photocatalysis (PC), Fenton (F) and photo-Fenton (PF), was investigated. The optimum removal of total suspended solids (TSSs, 81%) by chitosan coagulation was achieved at actual pH (4.3) for 400 mg L −1 coagulant dose. The maximum organic matter removals by F (85%) and PF (95%) processes were achieved after 2.0 and 1.0 h, respectively by using 15,000/1852 (w/w) ratio of H 2 O 2 /FeSO 4 . On the opposite, in PC experiments, after an initial decrease in the early minutes of the treatment, a subsequent increase versus irradiation time was observed for both UV absorbance at 280 nm and chemical oxygen demand (COD); probably a partial oxidation made some organics detectable only after treatment.

Research paper thumbnail of Endocrine disruptors compounds, pharmaceuticals and personal care products in urban wastewater: implications for agricultural reuse and their removal by adsorption process

Environmental Science and Pollution Research, 2013

In the last years, a lot of emerging contaminants, such as, endocrine disruptors compounds (EDCs)... more In the last years, a lot of emerging contaminants, such as, endocrine disruptors compounds (EDCs), pharmaceuticals, and personal care products (PPCPs) have been detected in wastewater. Because of their toxicity and possible adverse effects on the environment and humans, their release from urban wastewater treatment plants (UWWTPs) effluents should be minimized, particularly when a wastewater reuse for crops irrigation is expected. Many processes have been investigated for advanced treatment of UWWTP effluents as well as for emerging contaminant degradation; among these, adsorption process was successfully used to remove EDCs and PPCPs from wastewater. This article shortly reviews EDCs and PPCPs removal from UWWTP effluents by adsorption process using conventional and non-conventional adsorbents. The fate of EDCs and PPCPs in UWWTPs and the implications for agricultural wastewater reuse has been addressed too. In spite of the adsorption process looking to be a valuable alternative to other advanced technologies for the removal of emerging contaminants from wastewater, some gaps still remain to evaluate the actual feasibility at full scale. However, according to a few studies available in scientific literature on the use of both powdered activated carbon and granular activated carbon at full scale, adsorption process by activated carbon is a promising, potentially effective, and economically feasible solution for producing safe wastewater for agricultural reuse.

Research paper thumbnail of Advanced oxidation of catechol: A comparison among photocatalysis, Fenton and photo-Fenton processes

Desalination, 2009

The aim of this work was to compare the behaviour of Fenton, photo-Fenton and photocatalysis proc... more The aim of this work was to compare the behaviour of Fenton, photo-Fenton and photocatalysis processes to treat catechol solutions which are pollutants occurring in wastewaters from many industries. The effect of different process parameters, such as initial catechol concentration, H 2 O 2 /FeSO 4 ratio in Fenton and photo-Fenton oxidation, TiO 2 loadings in photocatalysis and irradiation times has been studied. Fenton and photo-Fenton (H 2 O 2 /FeSO 4 = 600/500 (w/w) and 30 min reaction time) processes allowed us to achieve a high efficiency in the mineralization of catechol (COD removals up to 83% and 96% respectively), and removal of aromaticity (UV 280 ) (up to 93% and 98% respectively), for an initial catechol concentration of 110 mg/l. On the opposite, photocatalysis was not effective in the removal of higher catechol concentrations (110 and 200 mg/l), whereas a significant removal of aromaticity versus time was observed for 50 mg/l. Gas chromatography-mass spectrometry analysis, performed under selected treatment conditions, showed that total removal of catechol can occur after Fenton (2000/500 w/w; 30 min), photo-Fenton (600/500 w/w; 30 min), and photocatalysis (3 g TiO 2 /l; 240 min) treatments.

Research paper thumbnail of Advanced treatment of urban wastewater by sand filtration and graphene adsorption for wastewater reuse: Effect on a mixture of pharmaceuticals and toxicity

Pharmaceuticals removal from urban wastewater by coupling conventional sand filtration with graph... more Pharmaceuticals removal from urban wastewater by coupling conventional sand filtration with graphene adsorption reactor (GAR) was investigated. During GAR regime phase, the percentage removal of the four investigated pharmaceuticals, (namely caffeine, carbamazepine, ibuprofen and diclofenac) was higher than 95% (98.2, 97.0, 95.5 and 97.0%, respectively). In spite of the high initial concentrations of the target pharmaceuticals (10 mg/L each) and 4 months of experimentation (62 days of adsorption treatment), typical breakthrough adsorption curves were not observed. Graphene adsorption treatment effectively decreased toxicity to Daphnia magna (0–50% immobilization), but only a slight improvement in germination index (phyto-toxicity tests) was observed after GAR treatment. Finally, graphene performances were compared with conventional (granular activated carbon) adsorption process, and the best performance in the removal of pharmaceutical mixture was quite poor (62% in terms of UV absorbance) compared to GAR (96%).