Homogeneous versus heterogeneous catalytic reactions to eliminate organics from waste water using H2O2

Homogeneous (Cu²⁺ ions) and heterogeneous (Cu²⁺-pillared clay) Fenton-like catalysts have been compared in the conversion of p-coumaric acid. The performances of the two classes of catalysts are similar for an analogous amount of copper, but there are some relevant differences in terms of (i) the presence of an induction time, (ii) the turnover frequency, (iii) the efficiency in the use of H₂O₂, (iv) the initial attack of p-coumaric acid (hydroxylation on the aromatic ring or oxidative attack on the double bond of the lateral chain), and (v) the effect of dissolved oxygen on the removal of total organic carbon (TOC). These differences were interpreted in terms of reaction network of generation of radical oxygen species and of organics conversion. The possible formation of a surface peroxo adduct coordinated to a copper binulcear site was also evidenced for the solid heterogeneous catalyst.     

S—94触变性不饱和聚酯树脂的制备和开发

在基体树脂中添加触变剂白炭黑，制成了Ｓ－９４触变性不饱和聚酯树脂。该树脂的触变指数比基体树脂高３倍多，改善了不饱和聚酯树脂的流变性。     

Enhanced properties of innovative laponite‐filled waterborne acrylic resin dispersions

In view of the possible future applications of waterborne automotive coatings, acrylic‐based nanocomposite dispersions were investigated by the simple mixing of aqueous laponite nanoparticle dispersions with acrylic resin dispersions. The mechanical, flow, and leveling properties of waterborne nanocomposite dispersion formulations containing increasing concentrations of silicate and nonvolatile components (nvc) in the acrylic dispersions were investigated. The results obtained were related to the morphological information obtained from transmission electron microscopy and wide‐angle X‐ray scattering measurements in liquid suspension or on the cured films. At low synthetic silicate loading when flow, leveling, and appearance properties were still acceptable for processing and application, a large increase in the modulus of the cured coating films was observed, which was a result of the special morphology of the laponite‐rich regions of the cured film. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 687–697, 2007     

De-oiling contaminated bleaching clay by high-pressure extraction

The disposal and re-use of spent bleaching clay from the vegetable oil processing industry is a problem of growing importance. Although today the only practical way of removal of the spent material is disposal, extraction with organic solvents is a well-known method of de-oiling contaminated bleaching clay. In our investigations we compare the extractibility of two different types of bleaching clays with CO₂ as a solvent. All experiments were carried out with a high-pressure extraction plant. The extraction and separation conditions, temperature and pressure, as well as the CO₂ mass flow, were varied during experiments. The aim of our investigations was a complete separation of the oil from the adsorbent. The latter should then be re-used as bleaching clay. The oil and the bleaching clay were analyzed and tested, respectively. The results show that oil of good quality can be recovered and the bleaching clay still has an activity approximately 50% of fresh clay.     

改性凹凸棒土净化含铬废水的研究

将凹凸棒土进行改性处理，用于对含铬废水中铬离子的吸附。本文研究了改性方式、凹凸棒土用量、吸附时间、pH值对含铬废水中铬离子净化率的影响。     

粘土结合耐火浇注料的研制

选用山东特级焦宝石、贵州焦宝石、河南三级高铝矾土熟料和山西阳泉特级高铝矾土熟料为骨料 ,河南三级高铝矾土熟料和山西阳泉特级高铝矾土熟料的球磨粉为基质 ,广西软质粘土为结合粘土 ,三聚磷酸钠、六偏磷酸钠、柠檬酸钠、酒石酸钠、酒石酸钾钠、碳酸钠 6种钠盐作分散剂 ,铝 60高铝水泥作促凝剂 ,配制了 4种不同组成的粘土结合耐火浇注料。在试验研究的基础上 ,分析了不同分散剂对广西软质粘土的分散效果 ,分散剂在粘土 -水体系中的分散机理和不同骨料对粘土结合耐火浇注料性能的影响。结果表明 :分散剂的分散效果以六偏磷酸钠为最好 ;以广西软质粘土作结合剂 ,用烧结良好的特级高铝矾土熟料作耐火骨料研制的粘土结合耐火浇注料 ,用水量少 ,气孔率低 ,结构致密 ,强度高     

Thermooxidative degradation of natural rubber/clay composite

The clay is treated with a reducing agent and an acid so as to obtain a clay containing various metal components with a variable‐valence state. Then, the clay is coprecipitated with natural rubber (NR) latex to prepare a vulcanized NR/clay composite. The degradation process of the NR/clay composite under hot air condition was studied dynamically by using a Fourier transform infrared spectrometer attaching an in situ sample cell and was also investigated using the TGA method. The test result obtained from the infrared spectrometry indicated that under low decomposition temperature, the decomposition products of the test samples mainly are ethylene, low molecular olefinic hydrocarbon, and carbonyl compounds. As the decomposition temperature rises, the low molecular olefinic hydrocarbon content decreases, the olefine with longer chain is formed, and a lot of alkane decomposition products are formed at the same time. When the content of the metal components with a variable‐valence state in clay such as Cu, Mn, Co, and Fe increases, the oxidation products containing the carbonyl group, the olefinic hydrocarbon, and CO₂ in the decomposition product of the test sample also increase. The TGA result clearly shows a shoulder peak that appears by the side of the main peak on the DTG curve of NR/clay composite. With the increase in the content of metal components with variable‐valence state in clay, the initial degradation temperature of the test sample (T₀), the degradation peak temperature (T_p1), and the final degradation temperature (T_f1) in first‐stage reaction, as well as the degradation peak temperature (T_p2) and the last final degradation temperature (T_f) in second‐stage reaction of all the test samples more or less shift to the direction of low temperature; besides, the activation energy (E) of the reaction of the test samples more or less decreases. This means that the metal components with variable‐valence state promote the oxidative degradation of the clay–rubber masterbatch. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3809–3815, 2006     

Enhanced corrosion prevention effect of polysulfone–clay nanocomposite materials prepared by solution dispersion

A series of polymer–clay nanocomposite (PCN) materials containing polysulfone (PSF) and layered MMT clay were successfully prepared by effectively dispersing inorganic nanolayers of MMT clay in an organic PSF matrix via a solution dispersion technique. The synthesized PCN materials were subsequently investigated with a series of characterization techniques, including Fourier transform infrared (FTIR) spectroscopy, wide‐angle powder X‐ray diffraction (XRD) and transmission electron microscopy (TEM). The prepared PCN coatings with low clay loading (1 wt %) on cold‐rolled steel (CRS) were found to be superior in corrosion prevention to those of bulk PSF, based on a series of electrochemical measurements of corrosion potential, polarization resistance, corrosion current and electrochemical impedance spectroscopy (EIS) in a 5 wt % aqueous NaCl electrolyte. The effects of material composition on the molecular barrier, mechanical strength and optical clarity of PSF and PCN materials, in the form of membranes, was also studied by molecular permeability analysis (GPA), dynamic mechanical analysis (DMA) and UV‐Visible transmission spectra, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 631–637, 2004     

Potential for use of crushed waste calcined-clay brick as a supplementary cementitious material in Brazil

The Brazilian ceramic industry generates large amounts of calcined-clay waste. This paper examines the factors that influence its potential for use as a partial replacement of Portland cement. Superplasticized mortars of equal workability containing ground crushed waste calcined-clay brick (GCWCCB) in the proportions of 10, 20, 30 and 40% as a cement replacement were analyzed through mechanical tests, pore structure characterization and durability tests. The results indicated the optimal percentages of substitution lies between 10% to 20%. The potential reduction of CO₂ emissions could be as high as 10% of current Brazilian cement industry emissions if this approach were to be fully implemented, and it could be eligible for “Clean Development Mechanism” credits under Kyoto protocol.     

Bulk polymerization of styrene in the presence of organomodified montmorillonite

The effect of montmorillonite (Cloisite 6A) on the bulk polymerization of styrene initiated by benzoyl peroxide (BPO) was studied by the dilatometric determination of the polymerization rates. The bulk polymerization rates increased as the montmorillonite input quantity increased. The effect became greater when the BPO concentration decreased. Under the assumption that clay participated in the radical initiation reaction of the chains, the reaction orders for clay and BPO were determined to be approximately 1.0 and 0.5, respectively. X‐ray diffraction and thermogravimetric analysis studies showed that the structure and properties of the obtained polystyrene (PS)/montmorillonite nanocomposites were greatly affected by the BPO concentration. With lower BPO concentrations, a larger interlayer distance and a higher extent of delamination for the clay were observed in the obtained PS/montmorillonite nanocomposites. The nanocomposites prepared with lower BPO concentrations also showed higher heat‐decomposition‐resistance temperatures. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1146–1152, 2005