2026-01-222026-01-222025-08-29MODESTO, Antônio Lucas Alcantara. Otimização do ph na remoção de íons cobre por zeólitas sintetizadas em escala semi piloto com aquecimento proveniente da variação de entalpia dos reagentes. 2026. 116 f. Trabalho de Curso (Graduação) – Faculdade de Engenharia Química, Instituto de Tecnologia, Universidade Federal do Pará, Belém, 2025. Disponível em: <https://bdm.ufpa.br/handle/prefix/9113>. Acesso em:.https://bdm.ufpa.br/handle/prefix/9113This study investigates the use of kaolin waste for zeolite synthesis, exploiting the heat released during sodium hydroxide dissolution, and the optimization of copper ion (Cu2+) removal as a function of pH. Zeolite synthesis was carried out under dynamic hydrothermal conditions, using kaolin waste calcined at 700 °C as the starting material. The heat during synthesis resulted from the enthalpy variation of sodium hydroxide dissolution, reaching a maximum temperature of 110 °C and stabilizing at 89 °C after 2 hours. X-ray diffraction analyses revealed kaolinite and quartz peaks in the kaolin waste, whereas in metakaolin only quartz and the appearance of an amorphous halo were observed, confirming the formation of metakaolinite. In the zeolitic product, zeolite A, hydroxysodalite, and quartz were identified, with mass fractions obtained by Rietveld refinement of 70 %, 29 %, and 1 %, respectively, all with Bragg residuals below 10 %, a weighted profile error of 16.06 %, and a chi-square value of 1.16. Scanning electron microscopy of the kaolin waste revealed a pseudohexagonal morphology with a “booklet-like” stacking, typical of kaolinite crystals. In metakaolin, this morphology was preserved, albeit with reduced stacking. The synthesized material exhibited cubic crystals characteristic of zeolite A and spherical particles attributed to hydroxysodalite. The point of zero charge (PZC) was determined to be approximately pH 9.24, indicating that copper ion removal is favored at pH values above this threshold. Adsorption experiments confirmed superior removal at pH 10.5 compared to pH 5. Adsorption kinetics were best described by the Elovich model, with 51.89 % removal after 120 minutes (adjusted R2 = 0.986; HYBRID = 0.025; BIC = 36.67) at pH 5, and 80.90 % removal after 120 minutes (adjusted R2 = 0.995; HYBRID = 0.006; BIC = 31.44) at pH 10.5. Regarding adsorption isotherms, the Sips model provided the best fit at pH 5 (adjusted R2 = 0.996; HYBRID = 0.116; BIC = 59.51), whereas the Freundlich model was more suitable at pH 10.5 (adjusted R2 = 0.996; HYBRID = 0.146; BIC = 79.63). In conclusion, the formation of zeolite A and hydroxysodalite, driven by the heat released during reagent dissolution, was confirmed by the characterization techniques applied in this study. Furthermore, optimization of copper ion removal was achieved at pH 10.5, a value above the determined PZC.Acesso AbertoResíduo de caulimReaproveitamentoZeólitaPCZAdsorçãoKaolin wasteValorizationZeolitePZCAdsorptionCNPQ::ENGENHARIAS::ENGENHARIA QUIMICATrabalho de Curso - Graduação - MonografiaAttribution-NonCommercial-NoDerivs 3.0 Brazil