Porous geopolymers have been extensively developed as adsorbent materials for wastewater treatment. Display of a good mechanical strength on porous adsorbent would indicate an effective practicality in applications. In this work, we prepare geopolymeric cubes from coal fly ash by potassium-activation at different ratios of silicate: hydroxide, all of which were tested for the removal of cationic dye from aqueous solution. All samples exhibited open-cell macropores ranging from 1 to 10 μm in diameter, great durability, and reusability for multiple times without a substantial loss of mass. At the ratio 3.5: 1 silicate: hydroxide, the geopolymer cube displayed a high compression strength at about 1.7 MPa, which is much higher than other similar geopolymers prepared by sodium-activation. Surprisingly, our geopolymeric cube at the ratio 0.3: 1 demonstrated a high adsorption capability of methylene blue at 84 mg/g after about 6 h contact time. Electron and vibrational spectroscopies suggested that the incorporation of potassium within the aluminosilicate structure of geopolymers was responsible for the adsorption of methylene blue.

多孔地质聚合物已被广泛开发为废水处理的吸附材料。在多孔吸附剂上显示出良好的机械强度将表明在应用中的有效实用性。在这项工作中，我们通过在不同的硅酸盐：氢氧化物比率下进行钾活化，从煤粉煤灰中制备了地聚合物块，所有这些都经过测试以从水溶液中去除阳离子染料。所有样品均表现出直径在1至10μm范围内的开孔大孔，出色的耐用性和多次重复使用性，而不会造成质量损失。在硅酸盐：氢氧化物的比例为3.5：1的情况下，地质聚合物立方体显示出约1.7 MPa的高抗压强度，这比通过钠活化制得的其他类似地质聚合物高得多。令人惊讶的是，我们的地聚合物立方体的比例为0.3：图1显示了约6小时的接触时间后，在84mg / g的亚甲基蓝具有高吸附能力。电子和振动光谱学表明，在地质聚合物的铝硅酸盐结构中掺入钾是亚甲基蓝的吸附原因。