Abstract This study investigated the effect of dolomitic lime incorporation on the microstructure and mechanical properties of metakaolin-based geopolymers activated by alkaline solution. Five geopolymer mixtures were prepared with the addition of 0.0%, 2.5%, 5.0%, 7.5%, and 10.0% dolomitic lime. The microstructure of the geopolymers was evaluated by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction analyses (XRD). The compressive strength of the mixtures ranged between 53.2 and 63.0 MPa after 28 days of ambient curing. SEM/EDS analyses showed that the main phases formed were the N-A-S-H gel together with the C-A-S-H and N-M-A-S-H gels in the mixtures with dolomitic lime. In summary, the results showed that the incorporation of dolomitic lime can significantly improve the microstructure and properties of geopolymers. metakaolinbased metakaolin based solution 00 0 0.0% 25 2 5 2.5% 50 5.0% 75 7 7.5% 100 10 10.0 SEM, SEM , (SEM) energydispersive energy dispersive Xray X ray EDS, EDS (EDS) XRD. XRD . (XRD) 532 53 53. 630 63 63. curing SEMEDS NASH N A S H CASH C NMASH M summary 0.0 2.5 5.0 7.5 1 10. (SEM (EDS (XRD 6 0. 2. 5. 7.

Resumo Este estudo investigou o efeito da incorporação de cal dolomítica na microestrutura e nas propriedades mecânicas de geopolímeros à base de metacaulim ativados por solução alcalina. Foram preparadas cinco misturas de geopolímeros com adição de 0,0%, 2,5%, 5,0%, 7,5% e 10,0% de cal dolomítica. A microestrutura dos geopolímeros foi avaliada por microscopia eletrônica de varredura (MEV), espectroscopia de energia dispersiva de raios X (EDS) e análises de difração de raios X (DRX). A resistência à compressão das misturas variou entre 53,2 e 63,0 MPa após 28 dias de cura ambiente. As análises SEM/EDS mostraram que as principais fases formadas foram o gel N-A-S-H juntamente com os géis C-A-S-H e N-M-A-S-H nas misturas com cal dolomítica. Em resumo, os resultados mostraram que a incorporação de cal dolomítica pode melhorar significativamente a microestrutura e as propriedades dos geopolímeros. alcalina 00 0 0,0% 25 2 5 2,5% 50 5,0% 75 7 7,5 100 10 10,0 MEV, MEV , (MEV) EDS (EDS DRX. DRX . (DRX) 532 53 53, 630 63 63, ambiente SEMEDS SEM NASH N S H CASH C NMASH M resumo 0,0 2,5 5,0 7, 1 10, (MEV (DRX 6 0, 2, 5,

The species Oryza sativa (rice) and Musa cavendishii (banana) are sources of cellulose-rich waste biomass in the Amazon region, Tocantins State. This research investigates the nanoscale production of cellulose through the interactions between three choline amino acid ionic liquids Ch[AA]IL and the respective fibers by pretreatment. To this end, the synthesis of three ILs was carried out: choline arginate Ch[Arg], choline glycinate Ch[Gly] and choline lysinate Ch[Lys], characterized by Fourier transform infrared spectroscopy (FTIR). The samples resulting from the pretreatment were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). It was possible to infer from the SEM micrographs that Ch[Arg] caused greater fiber breakage than the other ILs. The TEM analyses identified fibers up to 16 nm in diameter. Positive effects were observed in the diffractograms, although no crystallinity was obtained in the pretreated samples. Thermogravimetry curves showed that the fibers treated with Ch[Arg] showed higher thermal stability. rice (rice banana (banana celluloserich rich region State ChAAIL Ch AA IL end out ChArg, ChArg Arg , ChGly Gly Ch[Gly ChLys, ChLys Lys Ch[Lys] FTIR. FTIR . (FTIR) SEM, (SEM) TEM, (TEM) Xray X ray XRD (XRD TGA. TGA (TGA) Ch[Arg 1 diameter diffractograms stability Ch[Lys (FTIR (SEM (TEM (TGA

The metal-organic frameworks (MOFs) UiO-66-NH2, UiO-66-2,5-(OH)2, UiO-66-NO2, UiO-66-NDC, and UiO-66-BPDC were synthesized under solvothermal conditions using different functionalized organic linkers. The structures and properties of the samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and nitrogen adsorption-desorption isotherms. The crystal structures of these functionalized UiO-66(Zr) forms were similar. A series of functionalized UiO-66(Zr) samples were used in the adsorption of carbon dioxide (CO2). UiO-66-NH2 had the highest CO2 adsorption capacity (about 3.35 mmol g-1) due to its small polar -NH2 group. The performance of UiO-66-NH2 in CO2 adsorption at different temperatures was also determined. The amino-functionalized material possessed better adsorption properties at 273 K than at 303 K, while the CO2 working capacity of UiO-66-NH2 was fully recovered after cyclic regeneration. metalorganic metal MOFs (MOFs UiO66NH2, UiO66NH2 UiONH UiO 66 NH2, NH2 NH UiO662,5OH2, UiO6625OH2 UiOOH 2,5 OH 2, 2 5 UiO-66-2,5-(OH)2 UiO66NO2, UiO66NO2 UiONO NO2, NO2 NO UiO-66-NO2 UiO66NDC, UiO66NDC UiONDC NDC, NDC UiO-66-NDC UiO66BPDC UiOBPDC BPDC linkers Xray X ray diffraction spectroscopy analysis microscopy adsorptiondesorption desorption isotherms UiO66Zr UiOZr Zr UiO-66(Zr similar CO2. CO . (CO2) UiO-66-NH about 335 3 35 3.3 g1 g 1 g-1 -NH group determined aminofunctionalized amino 27 30 regeneration UiO66NH 6 UiO662 5OH2 UiO662,5OH2 UiO6625OH 25 UiO-66-2,5-(OH) UiO66NO UiO-66-NO (CO2 33 3. g- UiO66 5OH UiO662,5OH UiO-66-2,5-(OH (CO UiO6

Chitosan (CS) blends with collagen (CL) and Aloe vera (AV) have gained significant attention in the biomedical field due to their biocompatibility, biodegradability, and potential for wound healing applications. In this study, we investigated the preparation and characterization of CS/CL and CS/AV blends using selective precipitation and co-precipitation techniques. The synthesis processes were analyzed for yield and 4-hydroxyproline content (in CS/CL blends). The materials were characterized using bromatological analyses, viscosity measurements, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). These eco-friendly methods effectively promoted interactions between the biopolymers, resulting in homogeneous blends with tunable properties. Besides, they are simple, fast, safe, and require minimal infrastructure. This study demonstrated that selective precipitation and co-precipitation are effective methods for producing chitosan/collagen and chitosan/Aloe vera blends. These methods foster interactions and miscibility between the biopolymers, as confirmed by FTIR, XRD, viscosity, and 4-Hy content analyses. They also align with green chemistry principles by avoiding organic solvents, reducing environmental risks, and minimizing waste. The high yields achieved, especially for CS/AV blends (exceeding 96%), make these materials compatible with lyophilization procedures. The absence of segregated phases after appropriate washing underscores their suitability for pharmaceutical formulations and other applications. CS (CS CL (CL AV (AV biocompatibility biodegradability applications CSCL CSAV coprecipitation co techniques 4hydroxyproline hydroxyproline 4 . blends) analyses measurements Fouriertransform Fourier transform FTIR , (FTIR) Xray X ray XRD (XRD) SEM. SEM (SEM) ecofriendly eco friendly biopolymers properties Besides simple fast safe infrastructure chitosancollagen chitosan chitosanAloe 4Hy Hy solvents risks waste achieved exceeding 96%, 96 96% 96%) procedures (FTIR (XRD (SEM 9

BiOCl/KBiO3 p-n heterostructures with hierarchical mesoporous architectures were successfully synthesized via a facile in situ method. The X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) results indicate the formation of heterojunctions between BiOCl and KBiO3. The photocatalytic performance of the as-prepared samples was investigated by the degradation of dye Rhodamine B (RhB) under visible light irradiation. BiOCl/KBiO3 composite has never been used to photodegrade the RhB which is a common dye and very difficult to degrade. The results demonstrated that KBiO3 combined with proper amount of BiOCl nanosheets exhibited high efficiency in the photocatalytic process, and BiOCl/KBiO3 with the molar ratio of 70/30 demonstrated the highest photocatalytic activity due to its large surface area, excellent charge separation characteristics and the suppressed recombination of electron-hole pairs. The results of active species detection reveal that the superoxide radical anions (O2-), hydroxyl free radicals (·OH), photogenerated holes (h+) and photogenerated electrons (e-) reactive species work together for the photocatalytic degradation of RhB. A possible and new mechanism of photocatalysis that differs from other teams was also explored and proposed. The present study will benefit the development of the new p-n heterojunction photocatalysts and would be of great importance to meet ever-increasing environmental demands in the future. BiOClKBiO3 BiOClKBiO KBiO BiOCl/KBiO pn p n method Xray X ray XRD, XRD , (XRD) XPS (XPS SEM (SEM asprepared as prepared (RhB irradiation degrade process 7030 70 30 70/3 area electronhole hole pairs O2, O2 O (O2-) ·OH, OH ·OH (·OH) h+ h (h+ e (e- proposed everincreasing ever increasing future (XRD 703 7 3 70/ (O2- (·OH (h (e (O2 (O

Novel nanocomposites synthesized with pollen grain, as a precursor, were tested for CO2 adsorption performance. The pollen-derived carbons were obtained by direct calcination (PC), calcination followed by KOH-chemical activation (PCKOH), and MgO incorporation using high-energy ball-milling (PC-MgO and PCKOH-MgO). All the as-prepared materials were texturally, morphologically and structurally characterized by N2 physisorption, scanning electron microscopy (SEM-EDS) and X-ray diffraction (XRD); CO2 adsorption/desorption was measured by thermogravimetry. The four materials were able to adsorb CO2 at 30 ºC and 1 bar, but PCKOH-MgO, with the high surface area (12.4 m2 g-1), total pore volume of (0.13 cm3 g-1) and microporosity, was the best (2.06 mmol g-1 and percentage of adsorption (Qad) = 9.06%, at 1 bar). This result is due to the synergic effect of both synthesis methods. Neither temperature (from 30 to 100 ºC), nor pressure (from 1 to 15 bar), improved the adsorption process of PCKOH-MgO. CO2 desorption times at 300 ºC were 47 min for PCKOH-MgO and 30 min for the other adsorbents, showing the possibility of cycling. Based on the obtained results, the PCKOH-MgO activated carbon nanocomposite stands as a promising adsorbent to be potentially used for industrial CO2 capture applications and to contribute to long-term solutions to avoid dangerous climate-change and reduce CO2 emissions. grain precursor CO performance pollenderived derived PC, PC , (PC) KOHchemical KOH chemical PCKOH, PCKOH (PCKOH) highenergy energy ballmilling ball milling PCMgO PCKOHMgO. PCKOHMgO . PCKOH-MgO) asprepared prepared texturally N physisorption SEMEDS SEM EDS (SEM-EDS Xray X ray XRD (XRD) adsorptiondesorption thermogravimetry 3 bar PCKOHMgO, MgO, 12.4 124 12 4 (12. m g1, g1 g 0.13 013 0 13 (0.1 cm microporosity 2.06 206 2 06 (2.0 g- Qad (Qad 906 9 9.06% bar. bar) methods from 10 ºC, ºC) MgO. adsorbents cycling results longterm long term climatechange climate change emissions (PC (PCKOH (XRD 12. (12 0.1 01 (0. 2.0 20 (2. 90 9.06 (1 0. (0 2. (2 9.0 ( 9.

The composites of poly (butylene adipate co-terephthalate) / poly (lactic acid) (PBAT/PLA) blend and montmorillonites functionalized using imidazole-derived ionic liquids with different carbon chain sizes (butyl, octyl, and dodecyl) proved to be a promising alternative for improving the thermal and mechanical properties of the polymer blend. Functionalization of montmorillonites by ionic liquids was confirmed by increasing the basal spacing, and spectroscopical and thermal analysis evidence. The composite synthesis was carried out by casting technique generating homogeneous polymeric films. X-ray diffraction analyses suggested that montmorillonite functionalization with the ionic liquid of the butyl carbon chain fostered exfoliation and incorporation of the clay into the polymer. Furthermore, an increase in the thermal stability and mechanical properties of the material was observed. The other composites formed between the PBAT/PLA blend and the montmorillonite functionalized by ionic liquids of higher carbonic chain showed micro composites formation. Thus, their thermal and mechanical properties had no significant improvements. butylene coterephthalate co terephthalate co-terephthalate lactic acid PBATPLA PBAT PLA (PBAT/PLA imidazolederived imidazole derived butyl, (butyl octyl dodecyl spacing evidence films Xray X ray Furthermore observed formation Thus improvements

RESUMO A estruvita (NH4MgPO4∙6H2O) é um fertilizante de liberação lenta obtido através da recuperação de fósforo e/ou nitrogênio de águas residuais geralmente pela adição de sais de magnésio. Neste sentido, objetivou-se avaliar a viabilidade da substituição de fontes comerciais de magnésio por fontes alternativas no processo de precipitação de estruvita, em termos de remoção de amônio e fosfato, e quantificação e caracterização do cristal precipitado. Os experimentos foram conduzidos em escala de bancada sob delineamento inteiramente casualizado a pH 9,5 através da precipitação de uma solução de efluente sintético com quatro diferentes fontes de magnésio: MgCl2∙6H2O, MgSO4∙7H2O, MgO e magnesita (MgCO3). Após pré-acidificação, soluções derivadas de fontes alternativas de baixo custo de magnésio removeram acima de 55 e 90% de nitrogênio amoniacal e fosfato em solução, respectivamente, e alcançaram por volta de 10 g L-1 de cristais precipitados. A proximidade dos resultados obtidos com soluções derivadas de fontes comerciais de magnésio (46ꟷ56% de remoção de nitrogênio amoniacal, 97% de remoção de fosfato, e mais de 6 g L-1 de precipitado formado) indicou que reagentes alternativos puderam facilmente substituir os comerciais se submetidos ao prévio processo de digestão, a fim de tornar o magnésio disponível em solução. A análise qualitativa por difratometria de raios-X confirmou a presença de estruvita e newberyita na maioria dos precipitados. NH4MgPO4∙6H2O NH4MgPO46H2O NHMgPOHO NH4MgPO4 6H2O NH MgPO H O (NH4MgPO4∙6H2O eou ou sentido objetivouse objetivou 95 9 5 9, MgCl26H2O MgClHO MgCl2 MgCl MgCl2∙6H2O MgSO47H2O MgSOHO MgSO4 7H2O MgSO MgSO4∙7H2O MgCO3. MgCO3 MgCO . (MgCO3) préacidificação, préacidificação pré acidificação, acidificação pré-acidificação 90 respectivamente 1 L1 L L- precipitados 46ꟷ56% 46ꟷ56 ꟷ (46ꟷ56 97 formado digestão raiosX raios X NHMgPO NH4MgPO HO (MgCO3 46ꟷ5 (46ꟷ5 (MgCO 46ꟷ (46ꟷ

ABSTRACT Struvite (NH4MgPO4∙6H2O) is a slow-release fertilizer obtained through phosphorus and/or nitrogen recovery from wastewaters, usually by adding magnesium salts. In this sense, the aim was to evaluate the viability of replacing commercial magnesium sources with alternative ones in the struvite precipitation process regarding ammonium and phosphate removal and precipitated crystal quantification and characterization. Experiments were conducted on a bench scale in a completely randomized design at pH 9.5 by precipitation of synthetic wastewater solution with four magnesium sources: MgCl2∙6H2O, MgSO4∙7H2O, MgO, and magnesite (MgCO3). After pre-acidification, derived solutions from low-cost alternative sources of magnesium removed above 55 and 90% of ammonium nitrogen and phosphate in solution, respectively, and reached around 10 g L-1 of precipitated crystals. Results proximity obtained with solutions derived from commercial sources of magnesium (46ꟷ56% of ammonium nitrogen removal, 97% of phosphate removal, and more than 6 g L-1 of precipitate formed) indicated that alternative reagents could easily substitute commercial ones if submitted to the previous digestion process, making magnesium available in solution. Qualitative analysis by X-ray diffraction confirmed the presence of both struvite and newberyite in most precipitates. NH4MgPO4∙6H2O NH4MgPO46H2O NHMgPOHO NH4MgPO4 6H2O NH MgPO H O (NH4MgPO4∙6H2O slowrelease slow release andor or wastewaters salts sense characterization 95 9 5 9. MgCl26H2O MgClHO MgCl2 MgCl MgCl2∙6H2O MgSO47H2O MgSOHO MgSO4 7H2O MgSO MgSO4∙7H2O MgO MgCO3. MgCO3 MgCO . (MgCO3) preacidification, preacidification pre acidification, acidification pre-acidification lowcost low cost 90 respectively 1 L1 L L- crystals 46ꟷ56% 46ꟷ56 ꟷ (46ꟷ56 97 formed Xray X ray precipitates NHMgPO NH4MgPO HO (MgCO3 46ꟷ5 (46ꟷ5 (MgCO 46ꟷ (46ꟷ

Palygoskite pellets were synthesized with lignin and WAX® and subjected to technological characterization for application in the remediation of Pb ions contained in aqueous effluents. X-ray diffraction (XRD) characterization of the palygorskite:lignin:WAX® material in a proportion of 70:15:15 revealed that the heat treatment of the pellets did not compromise the crystalline structure of the palygoskite. Texture analyses demonstrated that the surface area increased after synthesis and heat treatment, thus increasing the adsorption capacity. Regarding porosity, X-ray microtomography revealed that the pellets exhibit an irregular and porous spherical morphology with interconnected pores. Adsorption tests showed a removal of 73% of PbII contained in aqueous effluents after 15 min, with equilibrium reached in 60 min (88.36%). After the adsorption process, the presence of lead in the material was qualitatively confirmed through scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDS) images. The produced pellets exhibit promising adsorbent qualities, such as strength and effective PbII ion adsorption. WAX Xray X ray XRD (XRD palygorskiteligninWAX® palygorskiteligninWAX palygorskite palygorskite:lignin:WAX 701515 70 70:15:1 palygoskite capacity porosity pores 73 1 6 88.36%. 8836 88.36% . 88 36 (88.36%) process energydispersive energy dispersive SEMEDS SEM EDS (SEM-EDS images qualities 70151 7 70:15: 883 88.36 8 3 (88.36% 7015 70:15 88.3 (88.36 701 70:1 88. (88.3 70: (88. (88 (8 (

Silver film is commonly used to examine the structure and composition of molecules due to its surface-enhanced Raman scattering (SERS) effect. A simple method for preparing SERS silver films is proposed in this paper by electrodeposition in an amide-based liquid mixture (urea-acetamide-LiBr). The electrochemical behavior of silver in urea-acetamide-LiBr mixture was studied by cyclic voltammetry (CV) and chronoamperometry. It was found that the nucleation mechanism of silver shifts to instantaneous nucleation under diffusion control with increasing overpotential and temperature. The energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) investigations confirmed that the obtained deposits are pure silver. Scanning electron microscopy (SEM) analysis showed that the morphology of the silver deposits depends on the deposition potential and temperature. Rhodamine 6G was used as probe molecules for SERS experiments, showing that these new active substrates have high sensitivity to SERS response with high enhancement factors, of approximately 107, and enable Raman scattering even for diluted solutions. surfaceenhanced surface enhanced (SERS effect amidebased amide based ureaacetamideLiBr. ureaacetamideLiBr urea acetamide LiBr . (urea-acetamide-LiBr) CV (CV chronoamperometry temperature EDS (EDS Xray X ray XRD (XRD SEM (SEM G experiments factors 107 solutions (urea-acetamide-LiBr 10 1

Efavirenz, an antiretroviral drug, is a class 2 according to the biopharmaceutics classification system. Many dissolution enhancement systems have been tried and our group had success using wet milling to decrease particle size and granules were obtained by spray and freeze drying. In this paper we present data related to the upgrade in the process, raising the solids concentration in the suspension from 10 to 50% (m/v) and changing the drying step for a fluid bed granulation. After that, tablets were obtained. Granules and tablets were fully evaluated and a pharmacokinetic study was also performed with the granules. By powder X-ray diffraction (PXRD) and Fourier transform infrared spectroscopy (FTIR) it was possible to prove that there was no phase transition in the sample after milling and drying. Dissolution efficiency of 4 from 5 granules was higher than 90%, considering 83% for the raw material. Tablets were technically approved but the dissolution was impacted and just 2 out of 11 showed results > 80%. A high enhancement in the bioavailability was also observed, around 172%. So, it is possible to conclude that efavirenz microcrystals with enhanced dissolution and bioavailability can be formulated into tablets and are a viable system to develop a new drug product. Efavirenz process 1 50 m/v mv m v (m/v granulation Xray X ray PXRD (PXRD FTIR (FTIR 90 90% 83 material 80 80% observed 172 172% So product 9 8 17

Nanocomposites of GO/γ-Fe2O3 were used for magnetic dispersive solid-phase microextraction (m-d-μ-SPE) of six pesticides from river water samples, followed by the determination using high performance liquid chromatography-diode array detection. The synthesis of the nanocomposites is described and characterized using Fourier transform-infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. A central composite design was used to optimize the extraction time, sample solution pH, and adsorbent amount. The solvent type and volume for desorption and the effect of the ionic strength for adsorption were also investigated. The optimum adsorption conditions were achieved at 84 min of extraction time, pH 5.4, 115 mg of absorbent, and 1% (m/v) of NaCl, while the desorption solvent selected was 1.0 mL of methanol-acetic acid (9:1, v/v). The limits of detection ranged from 0.1 to 0.9 μg L-1, and a good precision was achieved with relative standard deviation (RSD) lower than 7.6% (n = 10). The accuracy of the method was accessed by recovery tests ranging from 82 to 117% (n = 3, RSD < 8%). GO/γFe2O3 GOγFe2O3 GOγFeO GO/γ Fe2O3 GO γ Fe O GO/γ-Fe2O solidphase solid phase mdμSPE m d μ SPE (m-d-μ-SPE samples chromatographydiode chromatography diode transforminfrared transform infrared spectroscopy Xray X ray diffraction microscopy time amount investigated 8 54 5 4 5.4 11 absorbent 1 m/v mv v (m/v NaCl 10 0 1. methanolacetic methanol acetic 91, 91 9 1, (9:1 v/v. vv v/v . v/v) 01 0. 09 L1, L1 L L-1 (RSD 76 7 6 7.6 n 10. 10) 117 3 8%. 8% 8%) γFe2O3 γFe GO/γFe2O GOγFe GOγFe2O GOγ FeO Fe2O 5. (9: L- 7. γFeO γFe2O (9 (

Phosphate species can affect aquatic ecosystems, as excess of this nutrient can cause eutrophication, generating environmental impacts. Lamellar double hydroxides have shown promise in removing phosphate at low concentrations (10-50 mg L 1). In this context, lamellar double hydroxides were synthesized interspersed with nitrates and humic substances, searching for a new product that favors phosphorus adsorption. X-ray diffraction showed the presence of characteristic peaks of lamellar double hydroxides and thermogravimetric analysis showed the decomposition behavior of lamellar structure. The adsorption capacity occurred quickly (< 30 min), being more efficient for lamellar double hydroxides with NO3. The maximum adsorption capacity showed results of 35.03 and 44.20 mg g 1 for lamellar double hydroxides with humic substances and lamellar double hydroxides with NO3, respectively. The complexation capacity showed that pH directly influences complexation, being greater for lamellar double hydroxides with humic substances at pH 6.5. Thus, nanostructured materials with humic substances are promising for use in contaminant remediation and adsorption can be a fast and efficient technique for use in soil and water. ecosystems eutrophication impacts 1050 10 50 (10-5 1. . 1) context Xray X ray structure < ( 3 min, min , min) NO3 NO 3503 35 03 35.0 4420 44 20 44.2 respectively 65 6 5 6.5 Thus water 105 (10- 350 0 35. 442 4 2 44. 6. (10 (1

Nanoparticles of TiO2 doped with low amount of Fe were synthesized from natural ilmenite obtained from alluvial gold mine wastes. The obtained TiO2 were characterized using X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), UV-Vis diffuse reflectance, thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), N2 adsorption-desorption isotherms, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The results confirm the formation of mesoporous TiO2 nanoparticles in anatase phase with 0.05 wt.% of iron possibly replacing some titanium places. All the characterizations were performed to the synthesized solid and the reference materials (TiO2 anatase and Degussa P25). The photocatalytic activity of both the synthesized solid and references were evaluated in the photo-oxidation of cyanide in aqueous medium under UV illumination. An experimental design type Box-Behnken was performed choosing three different parameters: the initial concentration of cyanide (50, 150 and 250 ppm) the catalyst load (0.1, 0.5 and 1.0 g L-1) and the oxygen source. The percentage of cyanide conversion was chosen as response in the design obtaining as optimal conditions [CN-]0 = 50 ppm, catalyst load = 0.6 g L-1 and air bubbling. Under these conditions it was reached 32, 32 and 89% of cyanide conversion for Fe-TiO2 synthesized, TiO2 anatase and Degussa P25, respectively. TiO wastes Xray X ray XRD, XRD , (XRD) XRF, XRF (XRF) Fouriertransform Fourier transform FTIR, FTIR (FTIR) UVVis Vis reflectance analysisdifferential analysis differential TGA/DSC, TGADSC TGA/DSC TGA DSC (TGA/DSC) N adsorptiondesorption adsorption desorption isotherms TEM (TEM XPS. XPS . (XPS) 005 0 05 0.0 wt wt. places (TiO P25. P25 P P25) photooxidation photo oxidation illumination BoxBehnken Box Behnken parameters 50, (50 15 25 ppm 0.1, 01 1 (0.1 5 0. 10 1. L1 L source CN0 CN [CN-] 06 6 L- bubbling 3 89 FeTiO2 FeTiO Fe-TiO respectively (XRD (XRF (FTIR (TGA/DSC (XPS 00 P2 (5 2 0.1 (0. [CN- 8 ( (0 [CN

Abstract The improper disposal of this waste poses environmental challenges, which can be addressed through effective reuse strategies. This study aims to explore the potential of utilizing marine shell waste as partial substitutes for aggregates in concrete. The research involves investigating the physical characteristics of the recycled aggregate using Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) techniques to elucidate the contact surface with the paste. Additionally, chemical and mineralogical characteristics are analyzed through X-ray fluorescence and X-ray diffraction tests. The compressive strength test is conducted on concrete samples to assess the performance of these materials as both aggregate (shell type A) and filler (shell type B). The findings indicate that replacing up to 20% of marine shells as coarse aggregate and 10% as filler demonstrates feasibility for applications in structural concrete. Furthermore, up to 30% replacement can be directed towards non-structural concrete, providing a comprehensive understanding of the potential applications of marine shell residues in concrete production. challenges strategies AFM (AFM SEM (SEM paste Additionally Xray X ray tests A B. B . B) 20 10 Furthermore 30 nonstructural non production 2 1 3

Resumo As atividades de mariscagem e malacocultura produzem uma grande quantidade de resíduos sólidos compostos por conchas marinhas. O impacto ambiental do descarte inadequado pode ser atenuado com estratégias de reaproveitamento. O objetivo deste trabalho é investigar a viabilidade do uso de resíduo de conchas marinhas com substituintes parciais de agregados no concreto. As características físicas do agregado reciclado foram investigadas através das técnicas de Microscopia de Força Atômica (MFA) e Microscopia Eletrônica de Varredura (MEV) a fim de esclarecer aspectos da superfície de contato com a pasta; as características químicas e mineralógicas foram investigadas por meio dos ensaios de fluorescência de raios-X e difração de raios-X; e o ensaio de resistência à compressão foi conduzido em amostras de concreto foram moldadas para avaliação do comportamento destes materiais do comportamento destes materiais como agregado (concha tipo A) e fíler (concha tipo B). Concluiu-se que o uso de até 20% de substituição de concha marinha como agregado graúdo e 10% como filer mostrou viabilidade para aplicações em concretos estruturais e, de forma complementar, teores de até 30% podem ser direcionados à concretos não estruturais. reaproveitamento MFA (MFA MEV (MEV pasta raiosX raios X A B. B . B) Concluiuse Concluiu se 20 10 complementar 30 2 1 3