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Red discolorations are an effloresce phenomenon detect on the surface of stone objects and considered as damage factor in both esthetic and conservation points of view. It is very difficult to remove and seldom report about their weathering mechanism. Recently, numerous of red discolorations have affected the limestone objects of Lingyan Temple in Shandong province, one of the most important building materials in China. In order to set up the appropriate conservation remedy, it is essential to identify the origin, characteristics, composition, and the formation process of red discolorations. Several analytical and investigation techniques, such as X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), Micro-Raman spectroscopy (Raman), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS) were used to better understand the red discolorations. The results demonstrated that the discolorations on limestone surface have been caused by carbonic acid weathering process. The red discolorations consisted mainly of kutnohorite (Ca(Fe,Mg,Mn)CO3) and iron oxides. They showed tabular, lamellar, and granular morphologies, which originated from the in situ carbonic acid weathering of kutnohorite. After rainfall, the Ca, Mg, Mn ions with relatively high solubility were primarily leached from carbonatite phases. It was resulting in the sedimentation of red iron oxides through a chemical reaction and physical adhesion. Based on those analyses, a chelating agent (ethylenediamine tetraacetic acid disodium salt) was chosen to remove theses red discolorations on the stone object.

The spontaneous degradation of pigments in painting may occur depending on environment, especially the surrounding condition of high humidity and soluble salts. Even some of these are well studied, more investigations are still in need for heritage science. Paint cross sections from Vairocana Statue in Dazu Rock Carvings, one of World Cultural Heritage, Chongqing, China are studied by optical microscopy (OM), Raman spectroscopy (Raman) and mapping, and scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM–EDS). Ultramarine blue, emerald green, synthetic atacamite, vermilion, red lead, gold foil, orpiment, cerussite, gypsum and barite are identified as pigments. Moreover, lavendulan (NaCaCu5(AsO4)4Cl·5H2O) and mimetite (Pb5(AsO4)3Cl) are degradation products of emerald green (Cu(C2H3O2)2·3Cu(AsO2)2) and cerussite(PbCO3) originally used as green pigment with mixture. These secondary products is formed via multistep progresses as degradation of emerald green and cerussite, oxidation of arsenite ((AsO2)-), migration of arsenate ((AsO4)3-) and precipitation reaction of these ions with other necessary ions from environmental conditions. Based on the pigment and paint layer stratigraphy analysis, the paintings of the statue have been executed at least four times and the most recent may be after 1850s. The formation of lavendulan give rise to a highlight for identification of green copper-arsenic containing pigments and characterization of degradation in complex conditions.

Natural hydraulic lime (NHL) based grout has been widely used in construction project related to ancient architecture in recent decades. In order to improve grouting performance of NHL based grout, silica fume (SF) and silicon-acrylic latex (SAL) were incorporated in the preparation of grout. For the grout in fresh state, compared with control grout, bleeding rate of modified grout with SF and SAL incorporation decreased. Wettability, interfacial bond and simulated grouting properties of grout were improved. For the grout in hardened state, water absorption of grout decreased. Compactness, mechanical strength and salt resistance were improved. SAL played a more important role in improving both grout’s flexural strength and interfacial bond property between grout and consolidated matrix. Generally, combined use of SF and SAL made the grout with the most beneficial grouting performance.

Natural hydraulic lime (NHL)-based mortars were prepared by introducing isobutyltriethoxysilane (SO) and silica fume (SF) as partial replacement of NHL by percentage of 20%. Main physical, mechanical and durability properties of mortars were evaluated. Compared with control mortars, apparent density, water absorption and shrinkage of modified mortars decreased, mechanical and durability properties were improved. Generally, SF was more effective than SO in improving main physical and mechanical properties of mortars. The reason was attributed to pozzolanic reaction between SF and Ca(OH)2, which generated more hydrate product and refined pore structure. SF modified mortars showed the highest compressive strength (CS). The combined use of SF and SO showed the largest improvement in mortars’ flexural strength (FS) and bond strength (BS), for that SO played a bridge coupling role between components in mortars. Durability properties of mortars were greatly improved by the presence of SO and it was related to water repellency of SO. Mortars prepared with SF and SO had the highest durability.

Compared with other wall paintings, tomb murals are rarely and have been most seriously damaged by natural weathering, erosion of bacteria and vandalism. Traditional identification methods are time-consuming, laborious, and confined to the visible light range, which mainly relies on expert's experience, analogy and visual color. This calls for new recording methods for mural site protection, relics restoration and repairs. Hyperspectral imaging can capture pictures of spectral range from visible to near infrared light, which render visual enhancement of faded tomb murals. This paper presents a method that can extract faded mural pattern from the hyperspectral images of mural, taking the leaf-like mural patterns in typical Tang dynasty tomb in China as an example. In the method, the faded leaf-like patterns are highlighted through normalization of sensitive spectral bands and extracted by density slice and masking on image space. The result shows that the method can extract the target pattern efficiently with the simple operations.

A thermo- and pH-sensitive hydrogel was prepared by a facile free aqueous radical copolymerization of PEGMA and AAc without any crosslinkers for controlled drug delivery. The successful fabrication of hydrogels was confirmed by Fourier transform infrared spectroscopy (FT-IR) and thermo gravimetric analysis (TGA) measurements. The morphological, mechanical and swelling properties of the obtained hydrogels were studied systematically. The results showed that the morphological and mechanical behaviors of the resultant hydrogels were strongly affected by the content of AAc. Moreover, the obtained hydrogels showed an excellent thermo-, pH- and salinity sensitivities. Release profiles of 5-Fu were studied at different pH (gastric pH 1.2 and intestinal pH 7.4) and temperatures (25 °C and 37 °C). The results showed that the release is very low at pH 1.2/37 °C and high at pH 7.4/25 °C. The cytotoxicity of hydrogels to cells was determined by an MTT assay. The result demonstrated that the blank hydrogels had negligible toxicity to cells, whereas the 5-Fu-loaded hydrogels remained high in cytotoxicity for LO2 and HepG-2 cells. Results of the present investigation exemplify the potential of this novel thermo- and pH-sensitive hydrogel for the controlled and targeted delivery of the anti cancer drug 5-Fu.

Honglvcai (also named red and green porcelain) was prosperous in Jin Dynasty (1115–1234 AD) and had played a pivotal role in ancient ceramic development history in China, connecting with former glazed pottery Tang Sancai and later polychrome porcelain like Wucai and Doucai, but little scientific analysis has been reported up until the present day. In this research, one precious sherd unearthed from Linshui (one major site of Cizhou kiln system) in Hebei province was adopted as specimen for compositional and micro-structural analysis. Optical microscope (OM), X-ray fluorescence spectrometry (XRF) and energy dispersive spectrometry (EDS) in association with scanning electron microscope (SEM) were employed for investigation of the multi-colour decors and black outline. The extensive data reveal that although high lead content has been detected by surface analysis and the iron-rich pigment particles do locate in the middle of the whole vitrified region, the black outline in fact belongs to high temperature fired under-glaze painted decoration, rather than the deceptive low temperature fired lead based over-glaze decor or the generally believed ‘sandwich’ (glazed twice) structure. Furthermore, a corresponding criterion then has been established for differentiation among three main decorating methods, especially for the puzzling ‘sandwich’ effect scenario. Moreover, once this ongoing vexed debate over the nature of the black decoration in Cizhou kiln system has been clarified, it is then reasonable to deduce that, from idealistic and technical point of view, there is no difference between producing prototype like this sherd and real Doucai in Ming dynasty (1365–1644 AD) except for the types of under-glaze pigment. Overall, all these results together firstly provide realising scientific proofs for the origin of Doucai.

Hydrazinolyzed cellulose-graft-polymethyl acrylate (Cell-g-PMA-HZ), an efficient adsorbent for removal of Cd(II) and Pb(II) from aqueous solution, has been prepared by ceric salt-initiated graft polymerization of methyl acrylate from microcrystalline cellulose surface and subsequent hydrazinolysis. The influences of initial pH, contact time, and temperature on adsorption capacity of Cell-g-PMA-HZ as well as adsorption equilibrium, kinetic and thermodynamic properties were examined in detail. As for Cd(II) adsorption, kinetic adsorption can be explained by pseudo-second-order, while adsorption isotherm fits well with Langmuir isotherm model, from which maximum equilibrium adsorption capacity can be derived as 235.85 mg g−1 at 28 °C. Further thermodynamic investigation indicated that adsorption of Cd(II) by adsorbent Cell-g-PMA-HZ is endothermic and spontaneous under studied conditions. On the other hand, isotherm of Pb(II) adsorption fits well with Freundlich isotherm model and is more likely to be a physical-adsorption-dominated process. Consecutive adsorption–desorption experiments showed that Cell-g-PMA-HZ is reusable with satisfactory adsorption capacity.

Research on corrosion of archaeological porcelain glaze has rarely been carried out in the past, although corrosion damage precious heritage items continuously. A group of black-glazed porcelains from the Song Dynasty was excavated at a poor conservation site in Chongqing, and one of their fragments was investigated with optical microscope, SEM-EDX, FTIR and Raman spectroscopy. The results showed that the alteration crust of the glaze mainly consisted of silica-rich gel and contained a variety of heterogeneous phases, including the liquid phase separation structure and different crystals. The crystals mainly include hematite, magnetite, rutile, pseudobrookite and silicon dioxide. The inter-diffusion reaction between alkalis in glaze and hydrogenated species in contact solution was the main reaction, which led to the formation of silicon-rich hydrate layers. The amorphous layers eventually transformed into acicular silica crystals under long exposure to environment.

A pH-, temperature- and salinity responsive hydrogel with enhanced mechanical performance was developed based on semi interpenetrating network that was formed as a result of concurrent free radical polymerization of acrylic acid (AA), oligo(ethylene glycol) methacrylate (OEGMA) and 2-(2-methoxyethoxy) ethyl methacrylate (MEO2MA) along with chitosan (CS) for controlled drug delivery. The mechanical behaviors and swelling properties of these hydrogels were systematically investigated, and the results indicated that they were strongly affected by the content of AA and MEO2MA and exhibited strong pH-, temperature and salinity sensitivity. Bovine serum albumin (BSA) and 5-Fluorouracil (5-Fu) were used as the model drugs to evaluate the sustained release of the hydrogel. The result indicated that the amount of both drugs released was relatively low in acidic condition (pH 1.2) but high in neutral environment (pH 7.4), and the release rate of the drugs was slower at 37 °C than that at 25 °C. Cytotoxicity results suggested that the blank hydrogels had negligible toxicity to normal cells, whereas the 5-Fu-loaded hydrogels remained high in cytotoxicity for LO2 and HepG2 cancer cells. These results suggest that the synthesized hydrogels have the potential to be used as an effective pH/temperature sustainable site-specific oral drug delivery in intestine and colon.

A novel physically cross-linked pH-responsive hydrogel with enhanced mechanical performance (PCAD) was prepared from chitosan (CS), acrylic acid (AA) and (2-dimethylamino) ethyl methacrylate (DMAEMA) via in situ free radical polymerization for controlled drug delivery. The successful fabrication of the hydrogels was verified by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) measurements. Scanning electron microscopy (SEM) and mechanical analyses demonstrated that the morphological and mechanical behaviors of the resultant hydrogels were strongly affected by the content of AA and DMAEMA. Moreover, the swelling properties of these hydrogels were systematically investigated, and the results indicated that they exhibited strong pH sensitivity. The drug delivery applications of such fabricated hydrogels were further evaluated, from which Bovine serum albumin (BSA) and 5-fluorouracil (5-Fu) were chosen as the model drugs for in vitro release. The results showed that the amount of 5-Fu and BSA released can be tuned by changing the composition of the hydrogel and the pH of the medium. Toxicity assays confirmed that the blank hydrogels had negligible toxicity to normal cells, whereas the 5-Fu-loaded hydrogels remained high in cytotoxicity for LO2 and HepG-2 cancer cells. As seen from the results, PCAD hydrogels seem to have a potential application in drug-delivery systems controlled by the external pH value for cancer therapy.

BACKGROUND Although methyl acrylate has been graft polymerized from cellulose and functionalized with hydrazine and hydroxylamine for removal of copper and nickel ions, the adsorption capacity was less than 80 mg g−1. The present work reported hydrazinolysis of cellulose-graft-polymethyl acrylate and remarkably improved adsorption capacity for Cu(II) and Ni(II) in aqueous solution. RESULTS Hydrazinolyzed cellulose-graft-polymethyl acrylate (Cell-g-PMA-HZ) has been prepared by ceric salt-initiated graft polymerization of methyl acrylate from microcrystalline cellulose surface and subsequent hydrazinolysis with hydrazine hydrate. The successful synthesis was confirmed by Fourier-transform infrared spectroscopy, 13C-NMR, elemental analysis, scanning electron microscopy and thermogravimetric analysis. Adsorption behavior of Cell-g-PMA-HZ for Cu(II) and Ni(II) were studied through batch static adsorption processes and column chromatography methods. The influences of graft yield, initial pH, contact time and temperature on adsorption capacity of Cell-g-PMA-HZ as well as adsorption equilibrium, kinetic and thermodynamic properties were studied in detail. Kinetic adsorption can be explained by pseudo-second-order and adsorption isotherms fitted with Langmuir isotherm model, from which maximum equilibrium adsorption capacity can be derived as 229.36 mg g−1 for Cu(II) and 173.91mg g−1 for Ni(II) at 28°C. Further thermodynamic investigation indicated that adsorption of Cu(II) and Ni(II) by adsorbent Cell-g-PMA-HZ was exothermic and spontaneous under the studied conditions. CONCLUSIONS Hydrazinolysis of cellulose-graft-polymethyl acrylate has been accomplished. As an adsorbent, the prepared Cell-g-PMA-HZ was reusable and fairly efficient for removal of Cu(II) and Ni(II) from aqueous solution. © 2015 Society of Chemical Industry

Cobalt blue is a famous pigment in human history. In the past decade it is widely reported that the cobalt aluminate has been detected in ancient ceramics as blue colorant in glaze, yet the acquired Raman spectra are incredibly different from that of synthesised references, necessitating a reassessment of such contradictory scenario with more accurate analytic strategies. In this study, micro-Raman spectroscopy (MRS) and scanning electron microscopy (SEM) in association with energy dispersive spectrometry (EDS) were performed on under-glaze cobalt pigments from one submerged blue and white porcelain shard dated from Wanli reign (1573–1620 CE) of Ming dynasty (1365–1644 CE) excavated at Nan'ao I shipwreck off the southern coast of China. The micro-structural inspection reveals that the pigment particles have characteristics of small account, tiny size, heterogeneously distribution, and more importantly, been completely enwrapped by well-developed anorthite crystals in the glaze, indicating that the signals recorded in previous publications are probably not from cobalt pigments themselves but from outside thickset anorthite shell. The further spectromicroscopic analyses confirm this presumption when the accurate spectra of cobalt aluminate pigment and surrounding anorthite were obtained separately with precise optical positioning. Accordingly, we reassess and clarify the previous Raman studies dedicated to cobalt blue pigment in ancient ceramics, e.g. cobalt blue in celadon glaze, and in turn demonstrate the superiority and necessity of coupling spectroscopic analysis with corresponding structure observation, especially in the characterization of pigments from complicated physico-chemical environment like antiquities. Thus, this study promotes a better understanding of Raman spectroscopy study of cobalt blue pigments in art and archaeology field.