Advanced hybrid materials for direct potable reuse as alternatives to activated carbon for removal of contaminants of emerging concern

Vinícius Diniz

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Author(s):	Vinícius Diniz Total Authors: 1
Document type:	Doctoral Thesis
Press:	Campinas, SP.
Institution:	Universidade Estadual de Campinas (UNICAMP). Instituto de Química
Defense date:	2025-03-11
Examining board members:	Susanne Rath; José Alberto Fracassi da Silva; Davi Gasparini Fernandes Cunha; José Carlos Mierzwa; José Roberto Guimarães
Advisor:	Susanne Rath
Abstract
As freshwater availability declines and global water consumption rises, water scarcity has become critical, driving the need for alternative water sources. Direct potable reuse (DPR) offers a promising solution, though it faces challenges such as advanced treatment requirements and identifying marker contaminants. This thesis focuses on the EPAR Capivari II facility in Campinas, São Paulo, Brazil, a non-potable water reuse plant that uses membrane bioreactor (MBR) technology. A pilot plant (350 L/h) was installed at EPAR Capivari II, incorporating reverse osmosis (RO), UV/H2O2 photoperoxidation, and granular activated carbon (GAC) columns to test different DPR treatment configurations. The study monitored 12 contaminants of emerging concern (CECs) in raw sewage and post-MBR effluent using bidimensional liquid chromatography coupled with mass spectrometry (LC-LC-MS/MS), prioritizing five for further investigation: caffeine, hydrochlorothiazide, saccharin, sulfamethoxazole, and sucralose. The RO-UV/H2O2-GAC process proved to be the most effective in removing these prioritized CECs, producing effluent that met Brazilian potable water standards (GM/MS Ordinance No. 888). This thesis also evaluated the performance of the pilot plant’s activated carbon (AC1) and a commercial activated carbon (AC2) in batch and continuous flow studies. Results indicated that both activated carbons had higher adsorption capacities for sulfamethoxazole and lower for sucralose, with the Sips model best fitting the adsorption data. Continuous flow studies showed that upward flow was more effective for contaminant removal, with AC2 outperforming AC1 due to its larger surface area. To enhance DPR efficiency, this thesis also explored the development of new materials, including TiO2-supported activated carbon (TiO2/AC) and porous sulfur polymers (PSPs). Various synthesis methods and TiO2 precursors were tested, with the sol-gel method using titanium isopropoxide yielding the most effective TiO2/AC material, increasing TiO2 efficiency up to tenfold compared to commercially available dispersed TiO2 nanoparticles. Additionally, PSPs were synthesized via inverse vulcanization using 1,3-diisopropenylbenzene (DIB) as a monomer and sodium chloride (NaCl) as a template for pore formation. Higher DIB content resulted in increased caffeine adsorption, while a higher sulfur content enhanced photocatalytic activity, achieving over 90% caffeine removal. In summary, the pilot plant at EPAR Capivari II successfully demonstrated the feasibility of the RO-UV/H2O2-GAC process in producing potable water according to regulatory standards. Comparative studies highlighted AC2’s superior performance due to its larger surface area. The exploration of TiO2/AC composites and PSPs underscores the potential of these materials to improve DPR systems' sustainability and effectiveness, emphasizing the ongoing need for innovation and optimization in water treatment technologies (AU)

FAPESP's process:	21/08123-0 - Advanced hybrid materials for direct potable reuse as alternatives to activated carbon for removal of contaminants of emerging concern
Grantee:	Vinicíus Diniz
Support Opportunities:	Scholarships in Brazil - Doctorate

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