Modified sericite mica was prepared by combining the intercalation of cetyltrimethylammonium bromide (CTAB) through ion exchange and surface modification of 3-aminopropyltriethoxysilane (KH550) with the following steps: high-temperature activation of sericite mica, acid activation, sodium modification, LiNO3 treatment, the ion-exchange intercalation of the cetyltrimethylammonium cation (CTA+) and surface modification of KH550. High-temperature activation was the most critical step for the modified sericite mica, and the number of hydroxyl groups of mica under high temperature directly affected the surface modification of KH550. The effects of various activation temperatures on the surface modification of sericite mica were investigated. The structure of activated sericite mica was intact when activation temperature was 600°C or 700°C, and the surface modification of sericite mica was not affected. The structure of activated sericite mica was partially destroyed at 800°C. The optimal temperature for activating sericite mica was 700°C. The structure and morphology of modified sericite mica were characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, Brunauer–Emmett–Teller (BET) analysis and loose bulk volume. The KH550 could not only chemically graft onto the surface of sericite mica, but also enter into the interlayer through electrostatic attraction after its end amino group was protonated. The interlayer spacing of modified sericite mica increased to 3.22 nm, indicating that it might be an excellent layered silicate for preparing clay–polymer nanocomposites.

Montmorillonite (Mnt), a clay mineral with a nanolayered structure, was combined with an Fe-based metal–organic framework (MOF; MIL-53(Fe)) using an in situ growth technique that yielded a novel eco-friendly clay-based adsorbent (MIL-53(Fe)@Mnt). The adsorbent was characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis and N2 gas adsorption. The MIL-53(Fe) particles grew on the surface of the nanolayered Mnt and the MIL-53(Fe) particle size became smaller. The adsorption performance of MIL-53(Fe)@Mnt was investigated by removing methylene blue (MB), and optimization experiments were carried out to study the effects of contact time, pH, initial dye concentration and adsorbent mass on the adsorption processes. The MIL-53(Fe)@Mnt exhibited excellent adsorption capacity for MB, namely 313.7 mg g−1, which was 3.02 times and 3.54 times greater than that of pure Mnt and MIL-53(Fe), respectively. Adsorption was fitted with the Langmuir isotherm model and followed a pseudo-second order kinetic model. The MIL-53(Fe)@Mnt obtained is a low-cost and eco-friendly adsorbing material and might be a candidate for removing dyes during water treatment.

The Qingliang Temple kiln located in Baofeng County, Henan Province, China, is the discovery site of Ru Kuan porcelain, which is one of the five famous porcelain types of the Song dynasty in China. The ‘Ru-type ware’ and unglazed firing bodies were unearthed from the Qingliang Temple kiln in 2014, and the excavation site was very close to the central firing area of Ru Kuan porcelain. In this paper, the chemical composition, firing temperature and phase structure of the Ru-type ware and unglazed firing bodies from the Qingliang Temple kiln were analysed systematically using energy-dispersive X-ray fluorescence spectrometry, high-temperature thermal expansion and X-ray diffraction. The raw-material sources of the Ru-type ware bodies with various glaze colours are consistent but differ significantly from those of the unglazed firing bodies. The firing temperatures of the Ru-type ware and unglazed firing bodies are 1150–1200°C and 950°C, respectively, which are considered underfired. Mullite, α-quartz, β-cristobalite and α-Fe2O3 are the main constituents of the Ru-type ware bodies, whereas α-quartz and anatase were identified in the unglazed firing bodies. The Ru-type ware is related to the Ru Kuan ware in terms of firing techniques and official use.

Polycarboxylate superplasticizer (PCE) is sensitive to the clay present in concrete aggregates. In particular, Montmorillonite (Mnt), an impurity inevitably contained in the aggregate, can significantly influence the performance of concrete. In an effort to improve the compatibility of PCE, a zwitterionic PCE with cationic amide groups and shorter side-chain lengths was synthesized via free radical copolymerization. The optimal synthesis condition was verified via Box-Behnken design. In addition to characterizing the PCE, the performance of PCE in cement pastes with or without Na-Mnt was examined and the underlying mechanism was explored. The results show that, compared with commercially available PCE, the required dosage of PCE for cements containing Na-Mnt decreased. Unlike commercially available PCE, no intercalation occured on the newly manufactured clay-tolerant PCE within the layers of Mnt, resulting in a greater sorption thickness and improved dispersion of the cements containing Na-Mnt.

Non-metallic raw materials are largely unexplored in many African countries. In an attempt to reduce this knowledge gap, kaolin occurrences in three promising regions of southern Mauritania were examined. The aim of the paper is to describe the occurrences and characterize the material in terms of mineralogy and potential technical use in the ceramics industry. The kaolins are geologically associated with various sedimentary rock units in either the Coastal Basin (Kaédi), the Mauritanide Belt (Hassi Abyad) or the Taoudeni Basin (Néma). Geochemical data show Al2O3 contents of between 9% and 38% (corresponding to 23–96% kaolinite). Samples from the Hassi Abyad and Kaédi regions have greater kaolinite contents on average and were further investigated mineralogically. The kaolin from the Néma region contained less kaolinite (<50 mass%). The region is also less accessible and hence is not considered further in this study. X-ray diffraction, X-ray fluorescence and infrared spectroscopy confirmed the geochemically calculated kaolinite contents of the kaolins and identified quartz, anatase and goethite as the remaining major mineral constituents. The degree of structural disorder of the kaolinites (determined by infrared spectroscopy) is generally greater in the Kaédi occurrences than at Hassi Abyad. Ceramic tests proved that all of these kaolin raw materials might be used for the production of ceramics, and some may even be used for fine ceramics. From an economic point of view, the Hassi Abyad deposit is interesting in terms of its quality and reserves, aspects that will be addressed in detail in a follow-up study.

This work determines the optimal palygorskite (Plg) content (maximum surfactant adsorption point) to achieve organophilization using the cationic surfactant cetyltrimethyl ammonium bromide (CTAB) at various concentrations. Adsorption assays were carried out in a finite bath after varying the content of Plg and CTAB in solution. In those assays, the effects of time, temperature, pH and thermodynamic characteristics were studied. The results were analysed using the Langmuir, Freundlich, Dubinin–Radushkevich and Tempkin adsorption models. The increase in clay content in the dispersion leads to a decrease in adsorption of surfactant on the clay. It was possible to obtain the optimal Plg content to achieve organophilization at various concentrations of CTAB surfactant. The experimental data fitted well to the Freundlich model. The Dubinin–Radushkevich and Tempkin isotherms confirmed the chemical adsorption of CTAB on Plg clay.

Acid activation was carried out by heating muds prepared from Ca-rich bentonite (CaB), sulfuric acid (H2SO4) and distilled water, yielding various bleaching earths (BEs). The roles of each of the process variables, namely mass fraction of H2SO4 (x) in the dried CaB and pure H2SO4 mixture, heating temperature (T) and contact time (t), in the activation were tested. The raw CaB and each BE were examined with X-ray diffraction, chemical analyses, N2 adsorption/desorption, pH-metry and tintometry. The BE contents in both the aqueous and oily suspensions were set to 2% by mass in order to measure the pH value and the bleaching power, respectively. The optimum conditions for the activation to obtain a BE having the same bleaching power (0.60) as Tonsil® Optimum Bleaching Earth for soybean oil were determined as x = 0.35, T = 100°C and t = 2 h. The bleaching power increased only marginally upon increasing the activation time from 2 h up to 10 h at a given x and T. After 10 h, significant changes did not take place in the bleaching power of the BE. The mass fraction of total structural metal oxide (y), pH value, specific pore volume (V), specific surface area (S) and mean internal diameter (D) of the mesopores for the optimized BE are y = 0.10, pH = 3.0, V = 0.31 cm3 g–1, S = 225 m2 g–1 and D = 7 nm. The pH and D values were more important for bleaching the alkaline refined soybean oil compared to the other parameters tested.

Geopolymers can be transformed into zeolites under certain synthesis conditions. However, zeolite formation is not frequently reported in KOH-activated geopolymers. This study attempted to explore zeolite synthesis through geopolymerization for a curing time of 24 h using mixed NaOH/KOH alkaline solution as an activator, and then applying the geopolymer-supported zeolites to immobilize Cd(II) in paddy soil. The K2O/M2O–H2O/SiO2 and K2O/M2O–OH–/SiO2 binary zeolite crystallization phase diagrams were obtained. Zeolite A, faujasite and sodalite formed at lower K2O/M2O molar ratios (0–0.2), ferrierite formation was favoured at a K2O/M2O molar ratio of 0.2–0.4 and zeolite K-I and zeolite F-K (both K-zeolites) were observed at a K2O/M2O molar ratio of 0.6. The geopolymer-supported zeolites had micropores and mesopores and specific surface area values of 44.2–74.8 m2 g–1. The material displayed a considerable Cd(II) immobilization efficiency (55.6–58.7% at 4–6 wt.% addition of zeolite).