Performing Department
(N/A)
Non Technical Summary
The US Environmental Protection Agency has estimated 14.5 million tons of plastic containers and flexible packaging were generated in 2018, of which only 30% is recycled or combusted for energy recovery, and the remainder is landfilled. The excessive use of plastics contributes significantly to greenhouse gases (GHGs) emissions and the mechanical breakdown of plastics, microplastic particles (<5 mm dimensions) poses a great threat to the ecosystem. For preventing the use of plastic packaging, the fiber-based molded pulp packaging products (MPPs) are among the most promising sustainable packaging owning to its renewability, recyclability, biodegradability, or compostability. The base formulation to produce MPPs, called "pulp", needs to be developed depending on the desired properties of MPPs. Virgin wood fibers and recycled fiber materials, such as waste printing papers, magazines, cardboard, and corrugated boxes, are traditionally used to make pulps. However, the rising prices of wood pulp and the sharp decline in supply of recycled newsprint are contributing to the need of developing other alternatives. Agricultural and food processing industries unavoidably generate tremendous amounts of plant fiber-based biowastes (PFBW). While PFBW contains high quality and/or quantity of alternative fibers, their compositions and fiber behavior (i.e., freeness, strength) differ from wood-based fibers. This project will develop high quality of pulp by modifying a wide range of plant fiber-based biowastes (PFBW) generated from agricultural and food processing via eco-friendly and energy-saving technologies. PFBW include, but are not limited to, fruit and vegetable processing byproducts, wine grape processing byproducts, brewers' spent grain (beer processing byproducts), spent coffee ground, and hemp hurd. These pulps will be created into a series of MPPs including single-serve food container or trays, fresh fruit and vegetable baskets, and plant pots by using our pilot-scale pulper and transfer-molded pulp machine. This project will also fabricate superhydrophobic coatings using biodegradable and edible materials via eco-friendly and low-cost methods, thus overcoming the limit of hydrophobic surface for MPPs. Therefore, this project not only generates new scientific knowledge about plant fiber-based biowaste and their behaviors in the pulp and MPPs, but also develop engineering and scaling-up technologies using our pilot-scale pulper and transfer-molded pulp machine for promoting commercialization of technologies and products. In addition, new information on the biodegradability and compostability, economic impact, and GHG emission of applied technologies for converting plant fiber-based biowastes into MPPs will be generated. Therefore, the goal of this project is to develop a circular bioeconomy for agricultural, food, and packaging industries by promoting environmental and economic sustainability and reducing GHGs emissions, landfill deposits of PFBW, and single-use plastics.
Animal Health Component
50%
Research Effort Categories
Basic
20%
Applied
50%
Developmental
30%
Goals / Objectives
The ultimate goal of this project is to promote environmental and economic sustainability and thus transition from a linear to a more circular economy for agricultural, food, and packaging industries by reducing GHGs emissions, landfill deposits of plant fiber-based biowaste (PFBW), and single-use plastics. Four specific research objectives are proposed:Objective 1: To investigate the chemical and lignocellulosic composition, cellulosic fiber morphology and behavior (strength, freeness, color, etc.) of PFBW abundantly generated from agricultural production and food processing in northwest pacific (NWP) region and to extract and modify functional components (lignocellulosic fibers, cellulosic fibers, lignin, microparticles, etc.) from PFBW that are essential in creating molded pulp packaging products (MPPs) by using eco-friendly and energy-saving technologies. PFBW include, but are not limited to, fruit and vegetable pomace, wine grape pomace, brewers' spent grain, spent coffee ground, and hemp hurd;Objective 2: To develop high freeness and fiber interactions of pulps with functional components from Obj. 1 to create MPPs fulfilling the desired performance and specification (e.g., mechanical and thermal properties, water-resistance, permeability, etc.). A series of MPPs including single-serve food container or trays, fresh fruit and vegetable baskets, and plant pots will be created using our pilot-scale pulper and transfer-molded pulp machine;Objective 3: To fabricate edible and biodegradable superhydrophobic coatings for the MPPs created from Obj. 2 to overcome the hydrophilic nature of MPPs at different temperature and humidity conditions of given packaging applications. Functional components obtained from PFBW are also used in superhydrophobic coating formulation along with other biodegradable or edible materials; andObjective 4: To evaluate biodegradability and compostability of the MPPs and to analyze the economic viability, sustainability/global warming impacts, and life cycle properties of the applied technologies for producing pulps and MPPs in comparison with the plastic products (i.e., polystyrene, PET).
Project Methods
EffortsBench-scale production of MPPs:The formulated pulps will be made into MPPs using our self-built manual molded pulp former connected with vacuum pump and air compressor. The product will be formed on the mold while applying vacuum, and air pressure will then be applied to blow off molded product from the mold at 17 psi. The MPP will be dried using an impingement oven at 80-120 °C until the moisture content reaches about 10%.Pilot-scale production of MPPs:The formulated pulps will be made into food container, tray, fresh fruit and vegetable basket, and plant pots using our automatic transfer molded-pulp machine under the ideal operation conditions identified above. Produced MPPs will be dried using the same impingement dryer. Drying temperature and time will be studied to prevent deformation of the products.Preparation and application of superhydrophobic coatings:Colloidal system (i.e., micro- or nano-particles) will be prepared by either the solvent extraction/evaporation (e.g., lignin, cellulose), anti-solvent precipitation (e.g., zein/pectin), and electrostatic crosslinking (e.g. chitosan). For hydrophobic barrier, a surfactant-free wax emulsion will be prepared by following the method of Wang & Zhao (2021). Briefly, beeswax or candelilla wax will be mixed with acetone and hexane (1:1, v/v) at a concentration of 20 mg/mL, and heated (65 °C for 30 min) to reflux. Prepared colloids will be added to wax solution to obtain wax emulsion upon cooling. The combination of colloidal system and hydrophobic matrix is applied via one-step single-layer coating using the spray coater nozzle. Coating density will be controlled by adjusting concentration of hydrophobic barrier and spray time. For two-step double-layer coatings, surfactant-free wax emulsion without colloids will be coated onto the surface of MPPs using the spray nozzle and allowed completely dry. After that, the same spray coating procedure for the colloidal system will be applied onto the coated MPPs, which forms the double layer with hydrophobic barrier (inner) and colloidal system (outer) giving both hydrophobicity and rough surface.EvaluationsChemical and lignocellulosic composition of PFBW: Methods that commonly used for analyzing chemical and lignocellulosic composition were adopted for comparing with other references. Raw and treated PFBW will be analyzed for water-insoluble solid content (%) (Belay et al., 2013), chemical composition (%) including water, carbohydrate, protein, fat and ash (AOAC, 2000), pectin (%), lignocellulosic composition (%), cellulosic fiber morphology, strength, and freeness. Pectin will be extracted by citric acid solution (pH 2.5), precipitated by ethanol, and calculated by the gravimetric method. Lignocellulosic composition will be analyzed through the continuous procedure of extracting lignin, hemicellulose, and cellulose.Mechanical, thermal, and hydrophobic properties of MPPs: Mechanical properties (i.e., flexural strength and strain and modulus of elasticity) will be measured following the methods mentioned above. Thermal properties will be measured using differential scanning calorimetry and thermogravimetric analysis. Water absorption and solubility will be analyzed following ASTM D570-98 and calculated as percentage of weight increase and decrease from the initial sample weight, respectively.Thermal and cold stability evaluation: The thermal stability will be tested under 85 ºC for 30 min, while cold stability will be evaluated by placing samples in a -20 ºC freezer for 24 h. After thermal and cold treatments, CA and SA will be re-measured.Biodegradability and methane production potential: The individual MPP and coated MFP samples from Objectives 2 and 3 will be mixed with an anaerobic bacteria culture, retrieved from an active digester at a local wastewater treatment plant. Serum bottles containing the sample and bacterial culture will be stored at a temperature of either 35 °C or 55 °C, and constantly mixed for a period of 30-60 days. Methane and carbon dioxide will be produced during the testing period due to the anaerobic degradation of the packaging and coating material. The methane generated from the material will then be measured and the methane potential of the material which is expressed as per mass of volatile solids added or chemical oxygen demand added will be calculated by subtracting the methane volume from a blank. The biodegradability will be calculated by dividing the cumulative biogas volume by the theoretical cumulative biogas volume at standard temperature and pressure conditions. More details information on the tests can be found in ASTM D 5210 developed by the American Society for Testing and Materials. The key collaborator, Dr. Liu's lab has all the necessary equipment and experience to conduct the BMP tests.Compostability: In container with drainage holes, 50 g of soil will be placed into the bottom of the container. MPP samples will be buried with 10 cm burial depth. Water will be added every 5 days. At 10-day intervals, MPP samples will be removed, excess soil will be rinsed off, and the samples will be dried at 105 °C for 24 h. The initial weight and weight of sample at different sampling times will be recorded. The percentage weight loss will be calculated as initial weight minus weight at sampling time divided by initial weight x100.Life cycle analysis (LCA): The LCA will be conducted following the ISO standards 14040 and 14044 with the goal of evaluating the environmental performance of developed MPPs for comparison with similar plastic products (i.e., polystyrene, PET) (ISO 14044, 2006). The system studied will be from cradle to grave and its boundary encompasses raw material extraction, biowaste conversion to functional components, pulping, transfer molding, coating and waste disposal (landfill) or conversion (methane production). The functional unit is defined as 1 ton of each MPP. Background data such as upstream production of raw materials and the data on downstream waste treatment will be taken from the Ecoinvent database v3.0 whenever available, and complemented by other data sources including literature, part lists, patents, or equipment and product specifications if necessary. Life cycle impact assessment will be performed using the TRACI 2.1 method developed by the U.S. EPA considering that this project is conducted in the U.S. context. While ten categories of midpoint environmental impacts will be calculated by TRACI, this project mainly focus on the global warming impact of MPP production from biowaste, in terms of global warming potential (GWP; kg CO2 eq.). All the calculation will be performed using the SimaPro v8.0 software (PRé Sustainability, Netherlands).Economic impact evaluation: As noted in both the engineering and economic literature, LCA and TEA are the standard methodologies that allow for the characterization of environmental and economic aspects of technologies. In this objective the long-term sustainability of MPPs will be further evaluated from the economic returns, environmental outcomes and social perspectives using a comprehensive, integrated impact assessment framework. We will develop an integrated, curated techno-economic analyses that reflect the project research findings on biodegradability and compostability of MPPs and incorporates and values the environmental findings from the LCA. The main economic framework will focus on producers and markets and comparisons made with similar plastic products used for food packaging products. Working with industry partners and reported values in the global warming and environmental literature, a matrix for identifying key economic and environmental thresholds and factors that influence the acceptance and adoption of innovative technologies for MPPs will be established.