Cotton Burr Research Articles

329 Evaluation and Prediction of Site and Extent of Protein Digestion of Feedstuffs Commonly Fed in Beef Cattle Finishing Diets

Abstract Meeting metabolizable protein requirements of finishing cattle without overfeeding protein requires reliable estimates of site and extent of digestion. Current estimates of rumen degradable (RDP) and undegradable protein (RUP), as well as intestinal digestibility of RUP (dRUP) may be inadequate. Thus, the objectives of this experiment were to quantify RDP, RUP, and dRUP of common feedstuffs and evaluate nutrient composition as a predictor of RDP, RUP, and dRUP. Ruminally cannulated steers (n = 6) consuming a finishing diet were enrolled in replicated 3 × 3 Latin squares. Within each Latin square period, steers were assigned a feedstuff classification for in situ ruminal incubation. Single-source ingredients were classified as grain (steam-flaked and whole-shelled corn, wheat, and milo), protein (wet and dried corn distillers grains, Sweet Bran, cottonseed meal, canola meal, and soybean meal), and roughage (cotton burrs, alfalfa hay, wheat hay, sorghum × sudangrass hay, wheat silage, and corn stalks). Nutrient composition was determined for all feedstuffs using wet chemistry procedures. Feedstuffs were lyophilized, ground through a 2-mm screen, aliquoted into in situ bags, and ruminally incubated for 0, 4, 8, 12, 24, or 48 h. Samples were composited within incubation time point, analyzed for crude protein (CP), corrected for microbial contamination, and fit to non-linear models to estimate RDP and RUP using calculated passage rate. Subsamples of in situ digested feedstuffs underwent in vitro pepsin-pancreatin digestion and CP analysis to estimate dRUP. Statistical analyses were conducted using JMP Pro 16.0 and R (v4.1.0). On average, RUP estimates were 37.0% decreased (P < 0.05) for protein ingredients, yet grains and roughages were not different (P > 0.73) compared with NASEM (2016) empirical values, respectively. However, average dRUP was 11.9% and 33.1% reduced (P < 0.01) for protein ingredients and roughages, yet grain dRUP was not different (P = 0.16) compared with NASEM (2016) values, respectively. Neutral detergent fiber (NDF) and CP explained a substantial portion of the variation in RDP (P < 0.01, R2 = 0.94, RMSE = 2.26). Acid detergent fiber, NDF, and CP explained considerable variation in dRUP (P < 0.01, R2 = 0.91, RMSE = 5.43). Models were predictive when applied to independent data from the literature for estimates of RDP (R2 = 0.93; RMSE = 3.72) and dRUP (R2 = 0.83; RMSE = 6.06). There was slope (-0.09; P < 0.05) and mean bias (-1.30; P < 0.01) for RDP prediction validation but only mean bias (4.90; P < 0.01) in dRUP prediction validation models. Collectively, these data suggest that dRUP of protein ingredients and roughages are less than values reported by the NASEM (2016). Furthermore, CP and NDF may be useful for predicting RDP, RUP, and dRUP.

Greenhouse Cultivation of Cucumber (Cucumis sativus L.) in Standard Soilless Media Amended with Biochar and Compost

Peat is one of the most commonly used substrates in soilless cultivation. However, peat mining produces a negative carbon footprint, which raises the need for alternative sustainable substrate media. To address this, we studied the impact of peat replacement with a combination of various biochars and cotton burr compost on the growth and yield of cucumber (Cucumis sativus L.), and nutrient concentration of media, plant leaf, and fruit in greenhouse conditions. Two experiments were conducted from Nov 2020 through Jan 2021 (Trial 1) and from Feb to Apr 2021 (Trial 2). The treatments were control (peat, vermiculite, and perlite at 2:1:1) and in the control peat was either fully replaced (hardwood biochar+compost, softwood biochar+compost, and hemp biochar+compost) or partially replaced up to 50% (v/v) (hardwood biochar+compost, softwood biochar+compost, and hemp biochar+compost). The control media was more acidic with lowest electrical conductivity than the other treatments. The leaf chlorophyll content and the photosynthetic assimilation rate varied among the treatments in both trials. The final dry shoot biomass was lowest in peat-dominated control treatment suggesting biochar-compost in the substrate media contributed in increased dry biomass of the cucumber plant. The total number of fruits per plant and total yield per plant was significantly increased in all the treatments with the highest in hardwood biochar+compost, compared with the control. The nutrient concentration of media, leaf, and fruit indicates that biochar-compost enhances the nutritional status of the media, which supplies essential nutrients to the plant leaf and fruit while growing in different substrate compositions. Our results suggest that the replacement of peat with full or partial proportions of biochar-compost can produce similar and, in some cases, even better growth, yield, and physiology in potted cucumber than in the unamended control treatment.

308 Effects of Roughage Source on Growth Performance, Carcass Characteristics, and Rumination Time of Beef Steers Fed Steam-flaked Corn Finishing Diets

Abstract We hypothesized that roughage source would not impact rumination time and growth performance if the different sources provided a similar concentration of dietary neutral detergent fiber (NDF) and physically effective NDF (peNDF). This experiment’s objective was to evaluate rumination time, and growth performance steers consuming finishing diets with differing roughage sources (corn stalks, cotton burrs, or wheat silage). Beef steers (n = 49; BW = 317 + 5.6 kg) were used in a completely randomized design with 3 dietary treatments. Steers consumed a steam-flaked corn-based diet containing corn stalks (CS), cotton burrs (CB), or wheat silage (WS) included at 7% (DM basis). Dietary NDF was similar (P = 0.36) across treatments. Each steer was fitted with a sensory collar to record daily rumination. Weekly ingredient and dietary samples were estimated for physically effective NDF (epeNDF) using the Penn State Particle Separator. Actual physically effective NDF (apeNDF) was calculated based upon rumination time. Neither initial nor final body weight (BW) differed between treatments (P > 0.52); nor did average daily gain (ADG), dry matter intake or carcass adjusted variables of FBW, ADG, empty BW, or empty body fat (P > 0.31). However, gain to feed (G:F) tended to differ (P = 0.06) between treatments. The CS diet had the greatest G:F with no difference (P = 0.75) between CB and WS. Dietary NDF and epeNDF were similar (P > 0.35) among roughage sources; however, CB had the least apeNDF, consistent with lower rumination time (P < 0.01). When energy values were calculated from animal performance, the CS diet had the greatest observed energy values, followed by WS and CB having the least. These results indicate roughage source impacted rumination time, although steers were fed a steam-flaked corn-based finishing diet with similar dietary roughage and NDF inclusions.

Effects of roughage type on particle separation, rumination, fiber mat characteristics, in situ degradation, and ruminal fermentation parameters in beef steers.

Six ruminally cannulated steers (average BW = 791 ± 71 kg) were used in a replicated 3 × 3 Latin square experiment to determine the effects of roughage type on rumination, fiber mat characteristics, and rumen fermentation variables. Three roughages were included at 7% (DM basis) in a steam flaked corn-based diet: cotton burrs (CB), wheat silage (WS), or corn stalks (CS). Steers were fitted with a sensory collar to record rumination behaviors in 2-h intervals at the beginning of the experiment. Each 30-d period consisted of 7 d of recovery, 14 d of diet adaptation, 7 d of rumination data collection (daily and bi-hourly average rumination), 1 d of rumen fluid collection, and 1 d of rumen evacuations. In situ degradation of individual roughages was determined for 4 d after period 3 evacuations. During rumen evacuations, ruminal contents were removed; the rumen fiber mat (RF) was separated from the liquid portion with a 2-mm sieve, weighed, and a subsample was dried. Data were analyzed using the MIXED procedure of SAS with steer as the experimental unit and roughage (CB, WS, and CS) as the main effect. Dry matter intake (DMI) was not different for CB and WS (P = 0.25) and greatest for steers consuming CS diet (P ≤ 0.01). Roughage type did not influence the weight of the RF dry matter (%; DM; P = 0.92), RF weight (P = 0.69), or RF:DMI ratio (P = 0.29). Daily rumination (min/d) did not differ among roughages (P = 0.40), but min of rumination/kg of DMI was greatest for CS (18.0 min), min/kg of NDF was greatest for WS (89.8 min; P = 0.02), and min/kg of peNDF was greatest for CS (132.4 min; P ≤ 0.01). Wheat silage had the greatest percentage of soluble and degradable DM. Rumen fiber mat did not differ for roughages, although rumination min/kg of DMI and peNDF was greatest for steers consuming CS and WS. In situ degradation determined that CB-R and CS-R had the greatest percentage of ruminal undegraded DM. Based on the objective of the experiment, roughage type did not influence daily rumination or fiber mat characteristics.

251 Effects of Roughage Source on Rumination Time and Ruminal Ph in Steers Fed a Steam-flaked Corn Finishing Diet

Abstract Research is limited on how physically effective fiber from various roughage sources aids in rumination time and ruminal pH of finishing beef cattle. This experiment’s objective was to evaluate rumination time and ruminal pH of beef steers consuming finishing diets with varying roughage sources (corn stalks, cotton burrs, or wheat silage). We hypothesized that roughage type would not impact rumination time and ruminal pH if different sources provide similar dietary neutral detergent fiber (NDF). Ruminally cannulated steers (n = 6; average BW = 644.56 + 13.15 kg) were used in a 3 × 3 replicated Latin square with 3 dietary treatments and 3, 21-d periods (20-d diet adaptation, 1-d sampling). Steers consumed a steam-flaked corn-based finishing diet containing corn stalks (CS), cotton burrs (CB), or wheat silage (WS) included at 7% (DM basis) of the diet. Dietary NDF was similar across treatments. Steers were fitted with a sensory collar to record daily rumination (Allflex Livestock Intelligence). Ruminal pH was measured using a handheld pH probe on d-21 at 0, 3, 6, 12, 24 hr postprandial. The NDF and dry matter intake (DMI) were greatest for steers consuming the WS diet (P < 0.01) while CS and CB diets did not differ (P = 0.81). While dietary NDF and estimated physically effective NDF (peNDF) were similar among roughage sources, CB had the lowest actual peNDF, consistent with lower rumination time (P < 0.01) and lower ruminal pH (P = 0.29). This experiment’s results indicate that roughage source impacted rumination time despite feeding steers a steam-flaked corn-based finishing diet with similar roughage and NDF levels. Using rumination time (min/d) to determine peNDF was a better indicator of rumen function parameters than particle size measured via the Penn State Particle Separator equation.

Availability and Management of Cotton Byproducts in North Carolina: A State Survey

Abstract Whole cottonseed and cotton gin byproduct, also known as gin trash or cotton burrs, are known to be economical feed ingredients for beef cattle diets. There are several sources of information available to producers regarding the feeding of cotton byproducts; however, there is little information on the local supply chain and availability of these products. The objective was to survey cotton gins in North Carolina to determine how whole cottonseed and cotton gin byproduct are marketed. The 19-question survey was developed using Qualtrics survey software and emailed to all cotton gins in the state. Those who failed to respond to the weblink were contacted by phone. This resulted in a 73.5% response rate (n = 25 responses). Data were analyzed using the reporting feature of Qualtrics. On average, 7,716 metric tons of cottonseed and 1,523 metric tons of gin byproduct are produced per gin during a typical season. All respondents reported that the majority of their whole cottonseed is marketed out-of-state as livestock feed. All respondents reported that they either already sell or would consider selling cottonseed locally as cattle feed. In contrast, 78% of respondents reported that the majority of their gin byproduct stays in the state, with 40% being sold as cattle feed and the remaining 60% either being stockpiled and allowed to decompose on-site or used as compost. Of the respondents, 95% already sell gin byproduct locally as cattle feed or would consider doing so. The majority of respondents (92%) answered that they would like to be added to a directory to be distributed to cattle producers. This survey demonstrates that North Carolina cotton gins have cotton byproducts available and that they are interested in selling these locally to cattle producers.

Optimization of Liquefaction Parameters of Cotton Burrs (Gossypium hirsutum L.) for Polyurethane-Type Isolation Foams

Aim of study: The use of composites obtained from wood and similar lignocellulosic plants has increased all over the world. Because of the rapid depletion of forest natural resources, the rational use of declining wood raw materials and to evaluate environmental alternatives has gained importance. For this purpose, many alternative lignocellulosic raw materials are used as heat insulation material by producing foams.
 Materials and methods: This research compared the properties of liquefied using cotton burr after liquefaction under different acid concentrations, PEG 400-Glycerin/Cotton burr ratios, pore sizes, and PEG 400/Glycerin ratios. The cotton burrs were put in a reaction chamber at 160 °C for 2 h with the PEG 400-Glycerin/cotton burr and sulfuric acid in a glass balloon. 
 Main results: The maximum yield in the liquefaction of cotton burrs was found in the polyethylene glycol/glycerin ratio of 1:1. It has been found that the amount of unliquefied cotton burrs decreased with increasing of the acid concentration, reaction temperature and time.
 Research highlights: Consequently, the liquefaction of cotton burrs could be seamlessly used in the production of polyurethane-type foam.

Cotton Baby, and: The Boss’s Store, and: Their House Is No Sweet Home, and: After His Father Dies, and: On the Liberty Ship, and: The Port Battalion, and: You Call This a Bar?

Cotton Baby, and: The Boss’s Store, and: Their House Is No Sweet Home, and: After His Father Dies, and: On the Liberty Ship, and: The Port Battalion, and: You Call This a Bar? Margot Wizansky (bio) Cotton Baby It’s dawn in the cotton fieldand his mama’s singingtill the high sun takes away her song.He’s a cotton baby, lyingon the picking bag, draggeddown the cotton rowsthe whole day long.Mama’s face is shining,cotton bits stickingto her sweat-slicked skin.He cries hungry till Mamasits to feed him on the cotton bag.She can’t let that foremansee her cotton baby, can’t ever letthat foreman see her breasts. [End Page 87] The Boss’s Store not a real store anyway, unpainted walls chinkedwith cotton, open one day a week to buy what they can’t grow—coffee, cornmeal, the boss, fanning himself on a pile of feed bags, hauls himself up, opens a can of lard, scoops it out, goes behind the counter to cuttobacco with his knife and tally their debt in a dog-eared notebook, so hot a peppermint stick, cool burn, is what he wants,more than anything. What are you looking at, boy? Papa told him not to look, so he can’t say. Boss saysA cross-eyed boy’s bad luck and kicks him out of the store. He sits in the truck, so hot his head’s a baked yam about to burst; his arm hangs out the window to catch one flutter. Everything smells of dung; the sun’s cookingthe cotton fields the cart rumbles through on their way home. [End Page 88] Their House Is No Sweet Home His papa’s eyes are red with cottongin dust. He’s a white man’s sharecropper,same as being shackled for everything he needs, and his papa knows what he’ll never have,a weatherproof house, and for eachof his children, a pair of shoes and a bed. Sometimes when his papa’s sick of fighting,he tells them how he played the banjoat dances when he was young. While the children crowd around the woodstove,Papa roasts peanuts and tosses them.Conceived in slavery, he’s a Sunday preacher, unpaid, and from his pulpit,he preaches love of God, never sayslove each other. Their home is swearing and whipping, and he, the youngest boy,stands trembling. Papa never hugs himand he even fights with Mama, who stitches his worn socks into glovesto save his hands from cotton burrs. [End Page 89] After His Father Dies They’ve packed up what little they haveand hired a white man with a Ford coupeto drive them to his older sister in Kansas.He sits with his mother in the rumble seat.She’s made him wear his church clothesand it’s hot. Even the wind blowshot in his face. His first car ride,and the world is spinning.He’s trying to take it in, but hedoesn’t know how to look fast.Big houses, herds of cows, cornfields,cotton fields, field hands picking.Then the skies open, too muchrain for the driver to see the roadso they stop at a farmhouse to askif they can get out of the rain.The woman lets them stand on the porch.She brings a glass of sweet teafor the driver, a tin of water for his mama,until the woman’s husbandcomes up from the barn and shouts,Get them off my porch!The driver says, But it’s raining so hard,and the farmer says he doesn’tcare what it’s doing.He and Mama climb back intothat soaking rumble seat.She puts their shoes in a bagso they won’t get ruined.The driver stays on the porchtill the rain lets up. [End Page 90] On the Liberty Ship Camp Harahan, New Orleans, 1943 The president asks for volunteers.He drops out of high school, ready to go.Basic training is knots; hot, odorous weeks of knots...

Mechanical properties of polylactic acid composites reinforced with cotton gin waste and flax fibers

Interest in biodegradable polymers and sustainable materials has grown significantly in the last decade. Value addition of byproducts generated in agricultural processing systems is on the rise. Similarly, there is growing concerns with cotton ginners as the disposal of cotton gin waste (CGW) is becoming both financially expensive and an environmental concern. Therefore, this study investigated the possibility of producing environment friendly composites using biodegradable Polylactic acid (PLA) matrix reinforced with 10 to 30 wt. % of cotton burr and stem fibers from CGW. For comparison, hybrid composites were also prepared using CGW and stem fibers from flax residue of 100:0, 67:33, 33:67 and 0:100 ratios, while overall fiber weight fraction was fixed as 30%. The composites were produced by compression molding technique and the flexural property test was carried out following ASTM D790 standard. The test results showed that the flexural modulus increased by 42% with the addition of 30 wt. % of CGW as compared to neat PLA. Furthermore, the improvement of modulus of elasticity of composites containing 30 wt. % of CGW is comparable to hybrid composites reinforced with different percentage of flax fibers. However, the addition of fiber filler moderately altered the brittleness and reduced the flexural strength as compared to neat PLA. Nevertheless, the improvement of modulus of elasticity, and strain shows the possibility of using these composites as construction materials in low load or non-structural applications.

Short-term Effects of Composted Cattle Manure or Cotton Burr on Growth, Physiology, and Phytochemical of Spinach

Compost is increasingly used in horticultural crop production as soil conditioner and fertilizer because of its contribution to agriculture sustainability. The short-term (35 days after transplanting) effects of composted cattle manure or cotton burr on growth, physiology, and phytochemical of spinach (Spinacia oleracea L.) were evaluated in a greenhouse. Composted cattle manure at 5% or 10% mix rate (5Ca or 10Ca) greatly enhanced spinach growth as indicated by increased leaf number, area, fresh and dry weights (FW and DW), shoot FW and DW, and root DW. They also increased water use efficiency (WUE) and shoot:root ratio, and improved the photochemistry of mature leaves. Chlorophyll content also increased under 10Ca treatment. Composted cotton burr also improved spinach growth but only at 10% amendments (10Co), and was less efficient than composted cattle manure. Specific leaf area (SLA) decreased and succulence increased under all compost amendment indicating that compost could improve spinach quality. All soil amendments reduced the content of total phenolic and anthocyanin, while only 10Co and 5Ca treatments decreased flavonoid content and total antioxidant capacity. The content of carotenoid and protein increased in 10Ca treatment and amino acid content increased under both 5Ca and 10Ca treatments. The results indicated that compost, especially composted cattle manure mixed at 10%, improved spinach production and quality, and with proper application rate enhanced nutritional value by increasing carotenoid, protein, and amino acid contents while having little effect on total antioxidant capacity.

1413 Cotton burrs as alternative roughage to adapt beef steers to steam-flaked corn-based finisher diet

1413 Cotton burrs as alternative roughage to adapt beef steers to steam-flaked corn-based finisher diet

Impact of Fiber Treatment on the Oil Absorption Characteristics of Plant Fibers

Most plant fibers are good sorbents of oil; however, synthetic sorbents have a much higher sorption capacity (SC) than plant fibers. This study evaluated the effect of fiber treatments, specifically hot-water treatment and mercerization, on the absorption characteristics of selected plant fibers. Five common plant fibers—corn residues, soybean residues, cotton burr and stem (CBS), cattail, and oak—were evaluated for their absorption characteristics in crude oil, motor oil, deionized (DO) water, and a 80:20 mix of DO water. The fiber treatments included ground fiber (control), hot-water treatment at 80 °C for 4 h and 125 °C for 4 h, mercerization at room temp for 48 h, and mercerization at 300 °C for 1 h. The absorption capacity (AC) varied with fiber type, absorption medium, and fiber treatment. Mercerization at 300 °C increased the water absorption of soybean residue up to 8 g/g. Mercerization at room temperature and the hot-water treatment at 125 °C increased the crude oil absorption capacity. After certain treatments, the crude oil absorption capacity of CBS and corn fibers increased over 5 g/g, and the motor oil absorption capacity of cattail, corn, and soybean also increased to 4 to 5 g/g.

Physical Processing and Emission Characteristics of Firelogs from Cotton Ginning Byproducts

Cotton burr with stems (CBS), a byproduct from cotton ginning operations was evaluated for its suitability in firelogs. Firelog burn quality was examined by varying the CBS to paraffin wax ratio, and firelog processing conditions. The firelogs were burned in a wood stove to quantify the burn quality, burn time, product durability, and gaseous emissions. Firelog composition had no effect on the burn temperatures. Carbon monoxide (CO), ammonium (NH4), hydrogen (H2), and nitrous oxide (NO) gases were not detected in the gaseous emissions. Air emission samples from combustion showed the presence of n-alkanes, n-alkenes, oxygenated volatile organic compounds, polycyclic aromatic hydrocarbons (PAH), halogenated alkane, cyclic terpenes, benzene derivatives and naphthalene. Overall this study showed the potential of CBS as an alternative material for manufacturing firelogs.

Efficacy of an autodisseminator of an entomopathogenic fungus, Isaria fumosorosea, to suppress Asian citrus psyllid, Diaphorina citri, under greenhouse conditions

We are developing an autodisseminator (‘dispenser’) to inoculate Asian citrus psyllid with entomopathogens for the purpose of inducing epizootics in residential trees and abandoned groves, areas where chemical control is problematic. The dispenser prototype consisted of a bright yellow pleated tube coated with a spore formulation made from pulverized cotton burrs and blastospores of Isaria fumosorosea. Adult psyllids were released within an array of dispensers and potted citrus saplings in a greenhouse. After 24h, they were collected from the foliage, surface sterilized, and placed in an incubator. A mean of 55% of the adults developed mycosis (n=3 tests), demonstrating that the dispensers could cause primary infection. The potted plants used in the horizontal transmission tests were infested with immature psyllids; 27–35% of which became infected following contact with adults that had visited the dispensers (n=2 tests). When mycosed adult cadavers with mature conidia were placed near immatures on the potted plants, over 90% of the immatures mycosed, indicating that conidia from the cadavers were highly contagious. On dispensers left in the greenhouse for three weeks, the infectivity of blastospores exposed to direct sunlight decreased by 46% after 7d and by 60% after 20d, while infectivity levels remained high in blastospores that were shaded. These results confirmed that that the basic dispenser design was sound with respect to attracting and infecting psyllids. It requires further modification to work effectively under ambient conditions, since exposure to direct sunlight decreased blastospore infectiveness over time.

Environmental effects of using cotton burr compost mulch to establish roadside vegetation

Roadside vegetation is widely used in the highway design in USA to protect the right-of-way channels from water and wind erosion. Cotton waste used for compost has huge market potential for the establishment of roadside vegetation. However, limited information is available on the impact of cotton waste compost on soils while being used to establish roadside vegetation. The objective of this paper was to investigate the environmental effects using cotton waste compost to establish roadside vegetation. The basic experimental design consisted of a randomized split-plot. Ten subplot treatments were randomly assigned to either an irrigated or a non-irrigated main plot in each of three blocks. Physical evidence, visual observations, and laboratory analysis were combined with descriptive and inferential statistical methods to form the investigative component. The results showed that there was no significant change of soil pH, electrical conductivity, Na, K, Ca, Mg, sodium adsorption ratio, and soluble sodium percentage in soil salinity analysis before and after the application of cotton waste compost. Soil temperature was significantly ( P < 0.05) influenced by application of cotton waste compost at depths greater than 5 cm. Soil moisture was more effectively conserved by cotton waste compost manufactured topsoil or by a 10.2-cm layer of cotton waste compost. Cotton waste compost applied at depths greater than 5 cm retarded or prevented emergence of desired perennial grasses.

Development of Design Criteria for Denitrifying Treatment Wetlands

Subsurface wetlands are well suited for on-site applications because they provide odor and vector control and they mitigate public access issues (U.S. EPA, 1993). Artificial subsurface wetlands are typically designed with an inert rock medium, can be either planted or unplanted, and are designed so that the water flows below the surface of the wetlands through the porous medium. The medium provides a surface area for the growth of bacterial films but inhibits the carbon cycling from plant debris because the packing material prevents the plant debris from reaching the water. As a result, subsurface wetlands are only marginally successful at removing nitrogen from wastewater. The nitrogen removal that does occur is the result of plant assimilation and microbial denitrification that utilizes any remaining carbon source in the influent and from plant decay (Kadlec and Knight, 1996). To increase the denitrification performance, an alternative carbon source is required. Gersberg et al. (1983) demonstrated that the addition of carbon, in the form of methanol, stimulated bacterial denitrification and increased nitrate removal efficiencies to 95%. Based on previous research, it has been found that a variety of organic solids can be used simultaneously as media and as a carbon source to support the denitrification process. These include plant biomass (Gersberg et al., 1983), cotton burr and mulch compost (Su and Puls, 2007), wheat straw (Aslan and Turkman, 2003), sawdust (Robertson and Cherry, 1995; Schipper et al., 1998), and woodchips (Healy et al., 2005; Robertson et al., 2009). Schipper et al. (1998) demonstrated that porous groundwater treatment walls amended with sawdust were successful in removing nitrate from contaminated groundwater. Robertson et al. (2005) demonstrated that the proprietary Nitrex filters, which utilize a nitrate reactive material, produced septic tank effluent nitrate removal rates of up to 96%, remaining effective for at least five years, but removal rates were diminished during the winter months. The temperature of the water in a wetland system can significantly affect the rate of denitrification (Kadlec and Knight, 1996). The use of a readily available organic medium in a constructed subsurface wetland as a method for denitrification of nitrified septic tank effluent has not been investigated. This title belongs to WERF Research Report Series . ISBN: 9781843395331 (eBook)

Evaluation of cotton byproducts as fillers for poly(lactic acid) and low density polyethylene

Polymeric composites based on cotton burr and cottonseed bull have been prepared by melt blending and extrusion. For poly(lactic acid) (PLA) and low-density polyethylene (LDPE), addition of the fillers slightly changed the composite's thermal properties but significantly decreased the composite's mechanical properties. Heat treatment prior to extrusion resulted in composites with better tensile strength and Young's modulus. The use of maleic anhydride and peroxide only slightly improved the physical properties of the LDPE materials, but the effect was less clear for the PLA materials. The PLA-filler composites may be useful for lowering the cost of the materials in applications that can tolerate the decreased properties. In addition, the addition of fillers to LDPE might be beneficial in applications to improve stiffness or to improve biodegradability.

Conversion of cotton byproducts to mixed cellulose esters

Cotton byproducts, such as cotton burr and cottonseed hull, can be used as low-cost feedstock for the production of specialty chemicals. The conversion of these cellulosic byproducts into mixed cellulose esters, e.g., cellulose acetate propionate (CAP) and cellulose acetate butyrate (CAB), was studied. Instead of using the conventional process for preparing these materials, which uses the appropriate anhydrides, sulfuric or perchloric acid, and methylene chloride as solvent, an iodine-promoted process was used that requires no chlorinated solvent in the reaction mixture. Product ester ratios and degrees of substitution were determined by 1H NMR spectroscopy. At the conditions studied, acetic anhydride was only slightly more reactive than propionic anhydride in the formation of CAP, but acetic anhydride was noticeably more reactive than butyric anhydride in the formation of CAB.

Properties of thermoplastic composites with cotton and guayule biomass residues as fiber fillers

This study was conducted to evaluate the suitability of using residual plant fibers from agricultural waste streams as reinforcement in thermoplastic composites. Three groups of plant fibers evaluated included cotton burrs, sticks and linters from cotton gin waste (CGW), guayule whole plant, and guayule bagasse. The plant fibers were characterized for physical (bulk density and particle size distribution) and chemical properties (ash, lignin and cellulose contents). A laboratory experiment was designed with five fiber filler treatments, namely control (oak wood fiber as the filler – OWF), cotton burr and sticks (CBS), CBS with 2% (by weight) second cut linters (CBL), CBS with 30% (by weight) guayule whole plant (CGP), and CBS with 30% (by weight) guayule bagasse (CGB). The composite samples were manufactured with 50% of fiber filler, 40% of virgin high-density polyethylene (HDPE), and 10% other additives by weight. The samples were extruded to approximately 32 × 7 mm cross-sectional profiles, and tested for physico-mechanical properties. The CBS and CBL had considerably lower bulk density than the other fibers. Cotton linters had the highest α-cellulose (66.6%), and lowest hemicellulose (15.8%) and lignin (10.5%) of all fibers tested. Guayule whole plant had the lowest α-cellulose and highest ash content. Both CBS and guayule bagasse contained α-cellulose comparable to OWF, but slightly lower hemicellulose. Evaluation of composite samples made from the five fiber treatments indicated that fibers from cotton gin byproducts and guayule byproducts reduced the specific gravity of the composites significantly. However, the CBS and CBL samples exhibited high water absorption and thickness swelling, but the addition of guayule bagasse reduced both properties to similar levels as the wood fiber. The CGP exhibited significantly lower coefficient of thermal expansion. Composite samples with the five different fiber fillers showed similar hardness and nail holding capacity, yet oak fibers imparted superior strength and modulus under flexure and compression with the exception of the compressive modulus of CGB composites. In general, both cotton ginning and guayule processing byproducts hold great potential as fiber fillers in thermoplastic composites.

Chemical modification of cotton-based natural materials: Products from carboxymethylation

The processing of cotton generates a number of byproducts, two of which are cotton burr and cottonseed hull. A proximate analysis indicates that they contain about 30–32% cellulose, 17–19% lignin and lesser amounts of protein and oil. They differ in level of hemicellulose with burr containing ∼6% and hull containing ∼20%. Both materials can swell in aqueous NaOH–isopropanol solutions in which state they become susceptible to reaction with monochloroacetic acid. The products of this reaction consist of a water-soluble fraction (observed weight yields ranging from 28% to 55%) and a water-insoluble residue. The water-soluble fractions produce clear films that dissolve slowly in water with viscosities that are somewhat lower than for carboxymethyl products generated from purified cellulose. The products were characterized by NMR and IR and were found to consist mostly of carboxymethyl derivatives of cellulose and hemicellulose.