Quantification of the Vulcanizing System of Rubber in Industrial Tire Rubber Production by Laser-Induced Breakdown Spectroscopy (LIBS)

Determining metal elements in liquid samples using laser-induced breakdown spectroscopy and phase conversion technology

A phase conversion technology, involving the loading of brine samples with anionic polyacrylamide (APAM) colloidal droplets, is proposed to detect metal elements rapidly and accurately in liquid samples using laser-induced breakdown spectroscopy. The experimental conditions were optimized by comparing the obtained emission intensities and the signal-to-noise ratios, including the concentration of APAM, volume ratio of APAM solution to sample, delay time, and lens-to-sample distance (LTSD). Three kinds of complex brine samples with slightly soluble salts were used to test the analytical performance of the proposed method. The results show that the discrepancies of the concentrations of Li, Sr and Ca were 0.74-3.59%, compared with those obtained using inductively coupled plasma-optical emission spectrometry. This suggests that the proposed method can successfully determine metal elements in liquid samples, featuring short sample preparation time (less than 20 min), small sample volume (10 μL), and simple operation (no adsorption).

Review of Element Analysis of Industrial Materials by In-Line Laser—Induced Breakdown Spectroscopy (LIBS)

Laser-induced breakdown spectroscopy (LIBS) is a rapidly developing technique for chemical materials analysis. LIBS is applied for fundamental investigations, e.g., the laser plasma matter interaction, for element, molecule, and isotope analysis, and for various technical applications, e.g., minimal destructive materials inspection, the monitoring of production processes, and remote analysis of materials in hostile environment. In this review, we focus on the element analysis of industrial materials and the in-line chemical sensing in industrial production. After a brief introduction we discuss the optical emission of chemical elements in laser-induced plasma and the capability of LIBS for multi-element detection. An overview of the various classes of industrial materials analyzed by LIBS is given. This includes so-called Technology materials that are essential for the functionality of modern high-tech devices (smartphones, computers, cars, etc.). The LIBS technique enables unique applications for rapid element analysis under harsh conditions where other techniques are not available. We present several examples of LIBS-based sensors that are applied in-line and at-line of industrial production processes.

Design and Preparation of Polysulfide Flexible Polymers Based on Cottonseed Oil and Its Derivatives

Polysulfide-derived polymers with a controllable density and mechanical strength were designed and prepared successfully using bio-based cottonseed oil (CO) and its derivatives, including fatty acid of cottonseed oil (COF) and sodium soap of cottonseed oil (COS). The reaction features of CO, COF and COS for polysulfide polymers were investigated and compared. Based on the free radical addition mechanism, COF reacts with sulfur to generate serials of polysulfide-derived polymers. COF strongly influences the density and tensile strength of these polymer composites. Whereas COS was not involved in the reaction with sulfur, as a filler, it could increase the density and tensile strength of polysulfide-derived polymers. Moreover, the results showed that these samples had an excellent reprocessability and recyclability. These polysulfide-based polymers, with an adjustable density and mechanical strength based on CO and derivatives, could have potential applications as bio-based functional supplementary additives.

Sulfur determination in laser-induced breakdown spectroscopy combined with resonance Raman scattering

Sulfur is an essential element in industry, but it is difficult to be detected by laser-induced breakdown spectroscopy (LIBS). In this work, the disulfide radical Raman scattering was observed in sulfur plasma by combining LIBS with resonance Raman scattering (LIBS-RRS). Sulfur has been ablated by a focused laser beam to generate plasma, in which some sulfur atoms were combined to form disulfide radicals. The disulfide radical resonance Raman was excited by a 306.4 nm wavelength laser and observed at 710 and 1420 cm^-1 Raman shift. Using different contents of sulfur mixed with alumina (Al₂O₃) powder, both LIBS and LIBS-RRS calibrations were obtained at the same ablation laser energy. The calibration curve of sulfur atomic emission S I 921.28 nm was set up, and the linear coefficient (R²) was 0.285 and the detection limit (LoD) was 13.092 wt %. While the R² was 0.966 and LoD was 0.118 wt % for S₂ 710 cm^-1 in LIBS-RRS. The results indicate that disulfide radical Raman scattering by LIBS-RRS is promising for the determination of sulfur content and the diagnosis of molecular evolution in plasma.

Evaluation of heavy metal element detection in municipal solid waste incineration fly ash based on LIBS sensor

Heavy metal elements are the main pollutants in municipal solid waste incineration (MSWI) fly ash, the online detection of heavy metals in MSWI fly ash could benefit its subsequent solidification treatment and land-filling. In this paper, laser induced breakdown spectroscopy (LIBS) was introduced to the rapid measurement of heavy metal elements in MSWI fly ash. Considering the serious matrix effect in MSWI fly ash, the multiple linear regression model combined with internal standard method was used to establish the calibration curves of heavy metals. Validated samples were used to evaluate the performance of quantitative analysis models. The results show that linear regression coefficients (R²) of the calibration curves for Cd, Cr, Cu, Pb, Zn are 0.981, 0.988, 0.968, 0.978 and 0.993, respectively. The average relative error of the prediction results are from 6.8 to 20.3%. The detection limits of the heavy metal content are Cd (11.13 μg/g), Cr (44.87 μg/g), Cu (36.18 μg/g), Pb (10.83 μg/g), Zn (12.27 μg/g), respectively, which are far below those required in the Standard for Pollution Control on the Landfill Site of Municipal Solid Waste (GB16889-2008). All results indicate the great potential of LIBS sensor for online rapid detection of heavy metals in MSWI fly ash.