Chanel Fortier

Influence of Pyrolysis Temperature on Biochar Property and Function as a Heavy Metal Sorbent in Soil

While a large-scale soil amendment of biochars continues to receive interest for enhancing crop yields and to remediate contaminated sites, systematic study is lacking in how biochar properties translate into purported functions such as heavy metal sequestration. In this study, cottonseed hulls were pyrolyzed at five temperatures (200, 350, 500, 650, and 800 °C) and characterized for the yield, moisture, ash, volatile matter, and fixed carbon contents, elemental composition (CHNSO), BET surface area, pH, pHpzc, and by ATR-FTIR. The characterization results were compared with the literature values for additional source materials: grass, wood, pine needle, and broiler litter-derived biochars with and without post-treatments. At respective pyrolysis temperatures, cottonseed hull chars had ash content in between grass and wood chars, and significantly lower BET surface area in comparison to other plant source materials considered. The N:C ratio reached a maximum between 300 and 400 °C for all biomass sources considered, while the following trend in N:C ratio was maintained at each pyrolysis temperature: wood≪cottonseed hull≈grass≈pine needle≪broiler litter. To examine how biochar properties translate into its function as a heavy metal (NiII, CuII, PbII, and CdII) sorbent, a soil amendment study was conducted for acidic sandy loam Norfolk soil previously shown to have low heavy metal retention capacity. The results suggest that the properties attributable to the surface functional groups of biochars (volatile matter and oxygen contents and pHpzc) control the heavy metal sequestration ability in Norfolk soil, and biochar selection for soil amendment must be made case-by-case based on the biochar characteristics, soil property, and the target function.

Identification of cotton and cotton trash components by Fourier transform near-infrared spectroscopy

The high demand for cotton production worldwide has demonstrated the need for standardized classification of foreign matter present with cotton. Cotton trash can become comingled with fiber during the ginning and harvesting processes. The conventional instrumental method used to determine the amount of cotton trash present with cotton fiber, the high volume instrument (HVI), lacks specificity in the identification of individual trash components (leaf, etc.). Fourier transform near-infrared (FT-NIR) spectroscopy was investigated to distinguish the individual types of cotton trash from the fiber. In this study, the concept of monitoring differences in spectral bands of cotton and cotton trash by FT-NIR spectroscopy was demonstrated and provided a ‘proof of concept.’ A spectral library based on NIR spectral data and pre-processing methods was developed using cotton and cotton trash samples (hull, leaf, seed coat, and stem) yielding over 97% identification accuracy of cotton trash components in the prediction set.

Rapid measurement of cotton fiber maturity and fineness by image analysis microscopy using the Cottonscope

Two of the important cotton fiber quality and processing parameters are fiber maturity and fineness. Fiber maturity is the degree of development of the fiber’s secondary wall, and fiber fineness is a measure of the fiber’s linear density and can be expressed as mass per unit length. A well-known method for fiber maturity and fineness is a cross-section image analysis and microscopy measurement. In general, typical cross-section image analysis and microscopy methods for fiber maturity and fineness can be slow and tedious to perform. Much interest has been shown in improved and rapid routine measurements of fiber maturity and fineness in the laboratory. The Cottonscope® is a new small footprint instrument for measuring fiber maturity and fineness, consisting of a longitudinal measurement of weighted fiber snippets in water using polarized light microscopy and image analysis. A program was implemented to assess the potential and capabilities of the Cottonscope to measure cotton lint maturity and fineness and to determine the major operational impacts on the Cottonscope results. The measurement was fast and easy to perform. The major operational impact on the Cottonscope results was environmental conditions (room temperature and relative humidity), and its impact was a concern for fineness only. Very good method agreement was observed between the Cottonscope and image analysis and microscopy method for maturity and fineness, with moderate coefficients of determination, R2s, and low residuals. Recommended operational protocols for routine Cottonscope measurements were developed.

Near Infrared Measurement of Cotton Fiber Micronaire by Portable Near Infrared Instrumentation

In the U.S.A., cotton is classed (primary quality parameters) by the Uster ® High Volume Instrument (HVI), which must be maintained under tightly controlled laboratory environmental conditions. Improved and fast response quality measurement systems and tools are needed to rapidly assess the quality of cotton. One key area of emphasis and need is the development and implementation of new fast-response quality measurements that can be used not only in the laboratory but which also can be adapted to field and at-line quality measurements. A program was implemented to determine the ability of portable near-infrared (NIR) instrumentation to monitor critical fiber properties of cotton samples in the laboratory, at-line, and in the field, with initial emphasis on the laboratory measurement of cotton fiber micronaire. Micronaire is a key cotton property, and it is an indicator of the fiber’s maturity and fineness. Distinct NIR spectral differences between samples with varying micronaire were observed. A comparative evaluation was performed to determine optimum instrumental conditions for laboratory cotton micronaire measurements. The comparative evaluation established that the optimum instrumental conditions for laboratory measurements of micronaire was obtained with the use of a glass-covered sampling port and increased instrumental gain, with high R 2 values, low residuals, and with ≤ 12% outliers. For a NIR measurement with potential for multiple simultaneous analyses and non-laboratory measurements, the micronaire measurement was fast (< 3 min per sample) and easy to perform. The rapid and accurate laboratory measurement of cotton fiber micronaire with portable NIR instrumentation was demonstrated.

Chemical imaging of secondary cell wall development in cotton fibers using a mid-infrared focal-plane array detector:

Market demands for cotton varieties with improved fiber properties also call for the development of fast, reliable analytical methods for monitoring fiber development and measuring their properties. Currently, cotton breeders rely on instrumentation that can require significant amounts of sample, which complicates fiber development studies. Herein, we explored the use of high-resolution, Fourier-transform infrared (FT-IR) microscopy to examine cotton fiber secondary cell wall development in single fibers. Notably, there was a marked intensity increase for the C-O bending region near 1015 cm–1 and the C-H stretch at 2900 cm–1. These changes agree with those observed with macroscopic FT-IR tests. Chemical distribution maps and principal component analysis plots visually depict these spectral changes. Our results suggest the FT-IR microscopy can potentially be utilized as a tool to monitor and assess important fiber properties, such as cotton maturity, during fiber development.

Measurement comparison of cotton fiber micronaire and its components by portable near infrared spectroscopy instruments

Micronaire is a key cotton fiber quality assessment property, and changes in fiber micronaire can impact fiber processing and dyeing consistency. Micronaire is a function of two fiber components—maturity and fineness. Historically, micronaire is measured in a laboratory under tightly controlled environmental conditions. There is increased interest by the cotton and textile industry to measure key fiber properties both in the laboratory and in-field (non-controlled conditions), using small portable near infrared (NIR) spectroscopy instruments. A program was implemented to determine the feasibility of using portable NIR instruments to monitor fiber micronaire, maturity, and fineness. Prior to outside the laboratory measurements (field, warehouse, etc.), laboratory feasibility was performed to assess the NIR instruments’ capabilities. Comparative evaluations for fiber micronaire, maturity, and fineness were performed on three portable NIR instruments. Instrumental, sampling, and operational procedures and protocols for each instrument were established. Although representing different measurement technologies, very good spectral agreement was observed between the portable NIR instruments and a bench-top NIR unit used as a comparison. Rapid (less than 3 minutes per sample), easy to use, and accurate measurements of fiber micronaire and maturity were achieved, with regressions (R values) greater than 0.85, low residuals, and a low number of outliers observed for each NIR instrument. Improvements are required for the accurate measurement of fiber fineness by portable NIR instruments. Thus, for well-defined cotton fiber samples, the universal nature of the NIR measurement of cotton fiber micronaire and maturity by portable NIR instruments was validated.

Comparisons of Minicard ratings with ion chromatography sugar profiles of water extracts of cotton fibers and those of Minicard sticky spot materials

Specific levels of the carbohydrates melezitose and trehalulose deposited on the surface of cotton fibers are indicators of whitefly or aphid contamination. These deposits could cause stickiness problems during cotton ginning and textile processing. Cotton stickiness is highly complex, but surface carbohydrates may play the largest role in manifesting an issue. We utilized ion chromatography (IC) to identify and quantify nine sugars of interest present in the water extracts of 25 cotton samples to create sugar profiles for each sample: inositol, trehalose, glucose, fructose, trehalulose, sucrose, melezitose, raffinose and maltose. We compared the sugar profiles to the respective Minicard ratings of either NONE, LIGHT, MODERATE or HEAVY to draw correlations between the IC data and the rating. Trehalulose and melezitose in water extracts highly and positively correlate to Minicard ratings, confirming past researchers’ attribution of cotton stickiness to insect sugars. Trehalose and maltose also highly correlated, possibly due to their marker content in honeydew. Glucose and fructose moderately correlated to the ratings. IC studies of the collected Minicard sticky spot material found trehalulose and melezitose were the most prevalent sugars in HEAVY rated samples. Glucose and fructose were present in larger amounts in the MODERATE versus HEAVY rated samples. This result may indicate that the Benedict Test, which attributes these reducing sugars to stickiness, may not be sufficient for conjecturing a stickiness issue. When comparing the averages of the nine sugars present in water extracts versus those sugars contained in Minicard sticky spots, the overall distributions were very similar.