Abstract The effect of industrial waste from the cork industry on the strength and adsorption properties of zeolite-metakaolin based geopolymers has been studied. Cork residue 20% by weight was added to geopolymers that contained 0%, 25%, 50%, 75% replacement of metakaolin by zeolite in the structure. The SiO2/Al2O3 and Na2O/Al2O3 molar ratios were kept at 1 to reduce the environmental impact of sodium silicate and sodium hydroxide to the minimum. The compressive strength evolution after 1, 14 and 28 days in water and the heavy metals (Cd2+, Cr3+, Cu2+, Pb2+, and Zn2+) adsorption of the geopolymers were determined. It was found that addition of zeolite and cork residue in minor amounts concurrently aided in increasing the compressive strength of geopolymers. The adsorption properties, however, were dominated by the presence of cork residue and metakaolin which resulted in increasing adsorption of all heavy metal cations with increasing metakaolin in the structure. The adsorption was well fitted by the Langmuir model with R2 > 0.98 and the trend of adsorption was found to be Pb2+ > Cd2+ > Cu2+, Zn2+ > Cr3+. The significant improvement in compressive strength, as well as adsorption capacity observed with the addition of cork waste residue, connotes that it can be efficient as filler in geopolymers.

中文翻译：

---

软木废渣对偏高岭土-沸石基地质聚合物影响的新研究

摘要 研究了软木行业的工业废料对沸石-偏高岭土基地质聚合物的强度和吸附性能的影响。将按重量计 20% 的软木残留物添加到结构中含有 0%、25%、50%、75% 的偏高岭土被沸石替代的地质聚合物中。SiO2/Al2O3 和 Na2O/Al2O3 摩尔比保持在 1，以将硅酸钠和氢氧化钠对环境的影响降至最低。测定了在水中 1、14 和 28 天后的抗压强度变化以及地质聚合物对重金属（Cd2+、Cr3+、Cu2+、Pb2+ 和 Zn2+）的吸附。发现少量加入沸石和软木残留物同时有助于提高地质聚合物的抗压强度。然而，吸附特性 主要是软木残留物和偏高岭土的存在，这导致所有重金属阳离子的吸附增加，结构中的偏高岭土增加。吸附符合 Langmuir 模型，R2 > 0.98，吸附趋势为 Pb2+ > Cd2+ > Cu2+，Zn2+ > Cr3+。通过添加软木废渣观察到的抗压强度和吸附能力的显着提高，意味着它可以有效地作为地质聚合物中的填料。