In this study,vine pruning wastes(VPW)were used as raw material to develop an alternative activated carbon(VPW-AC)for adsorbing and concentrating rare earth elements cerium(Ce(Ⅲ))and lanthanum(La(Ⅲ))from synthetic a...In this study,vine pruning wastes(VPW)were used as raw material to develop an alternative activated carbon(VPW-AC)for adsorbing and concentrating rare earth elements cerium(Ce(Ⅲ))and lanthanum(La(Ⅲ))from synthetic and real leachate solutions.The Ce and La adsorption studies evaluated the effects of VPW-AC dosage,pH,contact time,rare earth initial concentration,and temperature.The VPW-AC adsorbent was subjected to many physicochemical characterization methods to correlate and understand its adsorptive performance.The characterization data indicate a carbonaceous adsorbent with a specific surface area of 467 m^(2)/g.Zeta potential indicates a material with a negatively charged surface at a pH higher than 3.1,which is extremely beneficial to cations removal.For both rare earths elements(REEs),the adsorption capacity increases with the increase of the pH,reaching its maximum at pH 4-6.The kinetic data are well fitted by Avrami-fractional o rder,while the Liu model agreeably fits equilibrium data.The maximum adsorption capacities for Ce(Ⅲ)and La(Ⅲ)are 48.45 and 53.65 mg/g at 298 K,respectively.The thermodynamic studies suggest that the adsorption process is favorable,spontaneous,and exothermic for both REEs.Pore filling,surface complexation,and ion exchange are the dominant mechanisms.Finally,the VPW-AC was subjected to the recovery of REEs from real phosphogypsum leachate,and it is proved that it can be successfully used to recover REEs in a real process.展开更多
A 9-month incubation experiment using composted and non-composted amendments derived from vine pruning waste and sewage sludge was carried out to study the effects of the nature and stability of organic amendments on ...A 9-month incubation experiment using composted and non-composted amendments derived from vine pruning waste and sewage sludge was carried out to study the effects of the nature and stability of organic amendments on the structural composition of organic matter (OM) in a semi-arid soil.The changes of soil OM,both in the whole soil and in the extractable carbon with pyrophosphate,were evaluated by pyrolysis-gas chromatography and chemical analyses.By the end of the experiment,the soils amended with pruning waste exhibited less organic carbon loss than those receiving sewage sludge.The non-composted residues increased the aliphatic-pyrolytic products of the OM,both in the whole soil and also in the pyrophosphate extract,with the products derived from peptides and proteins being significantly higher.After 9 months,in the soils amended with pruning waste the relative abundance of phenolic-pyrolytic products derived from phenolic compounds,lignin and proteins in the whole soil tended to increase more than those in the soils amended with sewage sludge.However,the extractable OM with pyrophosphate in the soils amended with composted residues tended to have higher contents of these phenolic-pyrolytic products than that in non-composted ones.Thus,despite the stability of pruning waste,the composting of this material promoted the incorporation of phenolic compounds to the soil OM.The pyrolytic indices (furfural/pyrrole and aliphatic/aromatic ratios) showed the diminution of aliphatic compounds and the increase of aromatic compounds,indicating the stabilization of the OM in the amended soils after 9 months.In conclusion,the changes of soil OM depend on the nature and stability of the organic amendments,with composted vine pruning waste favouring humification.展开更多
基金Project supported by the Brazilian National Council for Scientific and Technological Development/CNPq(405982/2022—4,303992/2021-2)。
文摘In this study,vine pruning wastes(VPW)were used as raw material to develop an alternative activated carbon(VPW-AC)for adsorbing and concentrating rare earth elements cerium(Ce(Ⅲ))and lanthanum(La(Ⅲ))from synthetic and real leachate solutions.The Ce and La adsorption studies evaluated the effects of VPW-AC dosage,pH,contact time,rare earth initial concentration,and temperature.The VPW-AC adsorbent was subjected to many physicochemical characterization methods to correlate and understand its adsorptive performance.The characterization data indicate a carbonaceous adsorbent with a specific surface area of 467 m^(2)/g.Zeta potential indicates a material with a negatively charged surface at a pH higher than 3.1,which is extremely beneficial to cations removal.For both rare earths elements(REEs),the adsorption capacity increases with the increase of the pH,reaching its maximum at pH 4-6.The kinetic data are well fitted by Avrami-fractional o rder,while the Liu model agreeably fits equilibrium data.The maximum adsorption capacities for Ce(Ⅲ)and La(Ⅲ)are 48.45 and 53.65 mg/g at 298 K,respectively.The thermodynamic studies suggest that the adsorption process is favorable,spontaneous,and exothermic for both REEs.Pore filling,surface complexation,and ion exchange are the dominant mechanisms.Finally,the VPW-AC was subjected to the recovery of REEs from real phosphogypsum leachate,and it is proved that it can be successfully used to recover REEs in a real process.
基金Supported by the Spanish Ministry of Science and Innovation (No. CTM 2007-60061)the CSIC-I3P fellowship from the Council of Scientific Research (CSIC) of Spain
文摘A 9-month incubation experiment using composted and non-composted amendments derived from vine pruning waste and sewage sludge was carried out to study the effects of the nature and stability of organic amendments on the structural composition of organic matter (OM) in a semi-arid soil.The changes of soil OM,both in the whole soil and in the extractable carbon with pyrophosphate,were evaluated by pyrolysis-gas chromatography and chemical analyses.By the end of the experiment,the soils amended with pruning waste exhibited less organic carbon loss than those receiving sewage sludge.The non-composted residues increased the aliphatic-pyrolytic products of the OM,both in the whole soil and also in the pyrophosphate extract,with the products derived from peptides and proteins being significantly higher.After 9 months,in the soils amended with pruning waste the relative abundance of phenolic-pyrolytic products derived from phenolic compounds,lignin and proteins in the whole soil tended to increase more than those in the soils amended with sewage sludge.However,the extractable OM with pyrophosphate in the soils amended with composted residues tended to have higher contents of these phenolic-pyrolytic products than that in non-composted ones.Thus,despite the stability of pruning waste,the composting of this material promoted the incorporation of phenolic compounds to the soil OM.The pyrolytic indices (furfural/pyrrole and aliphatic/aromatic ratios) showed the diminution of aliphatic compounds and the increase of aromatic compounds,indicating the stabilization of the OM in the amended soils after 9 months.In conclusion,the changes of soil OM depend on the nature and stability of the organic amendments,with composted vine pruning waste favouring humification.
