Gonçalves Dos Santos Mateus, Destefani Paquini Lucas, Leite Quintela Paulo Henrique, Roberto Profeti Luciene Paula, Guimarães Damaris
Postgraduate program in Chemical Engineering (PPEQ), Universidade Federal do Espírito Santo, Alto Universitário, s/n., Alegre, ES 29500-000, Brazil.
Laboratório de Pesquisa e Desenvolvimento em Eletroquímica (LPDE), Universidade Federal do Espírito Santo, Campus Goiabeiras, Av. Fernando Ferrari, Vitória, ES 29075-910, Brazil.
ACS Omega. 2025 May 15;10(20):20326-20340. doi: 10.1021/acsomega.4c11718. eCollection 2025 May 27.
Different materials have been used as adsorbents for removing micropollutants from industrial effluents, with vegetal-derived activated carbon being widely reported for dye removal, especially methylene blue (MB). However, its high cost and environmental concerns have driven the search for alternative adsorbents. Beyond developing new materials, understanding the interaction mechanisms between adsorbents and adsorbates is crucial. In this investigation, sodium (NaZ) and protonic (HZ) zeotypes were synthesized using diatomaceous earth (DE) residue as a silicon source and applied to MB dye adsorption. Batch experiments investigated adsorption rates, mechanisms, and thermodynamic spontaneity. The results showed rapid adsorption kinetics, with equilibrium achieved in about 5 min, following the Avrami model. The Weber and Morris model highlighted that the boundary layer significantly affects film diffusion and intraparticle diffusion. The adsorption process reached equilibrium governed by the Freundlich model, with favorable adsorption behavior for all adsorbents (nF values between 1 and 10). Additionally, the enthalpy values were found to be +39.66, + 5.70, and +21.79 kJ mol for NaZ, HZ, and DE, respectively. This was accompanied by a decrease in Gibbs free energy with a progressive increase in temperature, indicating a more spontaneous process at higher temperatures. These results suggest that the adsorption of MB onto the synthesized zeotypes is efficient, with fast kinetics and thermodynamic favorability. The zeotypes synthesized from diatomaceous earth exhibit promising characteristics for potential large-scale applications in wastewater treatment.
不同的材料已被用作从工业废水中去除微污染物的吸附剂，植物源活性炭被广泛报道可用于去除染料，尤其是亚甲基蓝（MB）。然而，其高成本和环境问题促使人们寻找替代吸附剂。除了开发新材料，了解吸附剂与被吸附物之间的相互作用机制至关重要。在本研究中，以硅藻土（DE）残渣为硅源合成了钠型（NaZ）和质子型（HZ）沸石，并将其应用于MB染料吸附。批量实验研究了吸附速率、机制和热力学自发性。结果表明，吸附动力学迅速，遵循阿夫拉米模型，约5分钟达到平衡。韦伯和莫里斯模型强调，边界层对膜扩散和颗粒内扩散有显著影响。吸附过程达到由弗伦德利希模型控制的平衡，所有吸附剂均具有良好的吸附行为（nF值在1到10之间）。此外，发现NaZ、HZ和DE的焓值分别为+39.66、+5.70和+21.79 kJ mol 。随着温度逐渐升高，吉布斯自由能降低，表明在较高温度下过程更自发。这些结果表明，MB在合成沸石上的吸附是高效的，具有快速的动力学和热力学优势。由硅藻土合成的沸石在废水处理的潜在大规模应用中表现出有前景的特性。
