Grantee Research Project Results
Final Report: Natural Surfactants in Paper Recycling
EPA Grant Number: SU833151Title: Natural Surfactants in Paper Recycling
Investigators: Rojas, Orlando J. , Austin, Chad , Tucker, Jarrod , Spence, Kelley , Hunter, Morris , Venditti, Richard , Dasmohapatra, Sudipta
Institution: North Carolina State University
EPA Project Officer: Page, Angela
Phase: I
Project Period: September 1, 2006 through August 31, 2007
Project Amount: $10,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2006) RFA Text | Recipients Lists
Research Category: P3 Challenge Area - Chemical Safety , Pollution Prevention/Sustainable Development , P3 Awards , Sustainable and Healthy Communities
Objective:
The objective of this project is to introduce new types of surfactants based on renewable materials (sugar and protein surfactants) for use in ink removal from recycled paper. By applying green chemistry approaches we not only will solve an important industry and environmental problem but also open an avenue for a number of products that are to be generated from the full utilization of forest and agricultural biomass. We selected a number of natural surfactants that were compared with toxic, conventional deinking formulations currently used in industry. The main methodologies involved measurement of bulk properties and deinking ability. Foamability and foam stability was studied since they are relevant to deinking flotation techniques. Detergency tests and piezoelectric techniques were used to unveil the fundamental differences in activity of the studied surfactants. Our tests were performed using bench-scale hydrapulper and flotation cells with temperature and shear rate control. Deinking efficiency was measured by image analysis and optical brightness. Fiber yield and loss were determined gravimetrically. Results from our project will facilitate better, safer operations and ensure a more widespread acceptance of deinking procedures which in turn will favor more employment, higher recycling rates, and obvious direct benefits to the environment. The replacement of petroleum-based surfactants with renewable ones implies the removal of toxic components in waste streams from the process, and will lead to an enhanced recycling process and subsequent reduction in landfilling.
Summary/Accomplishments (Outputs/Outcomes):
We have estimated the economic benefit that will be obtained by replacing synthetic surfactants with sugar-based surfactants. We found that the yield of the sugar-based surfactant process is 10% higher than the commercial based surfactant. The yield then contributes to more products being produced at a value of about $500/ton of paper and also an avoided cost of disposal of the rejects at about $50/ton. The overall cost savings using the sugar-based surfactant were estimated and we demonstrated that the benefits in higher yield outweigh the higher sugar-based surfactant costs, making the replacement profitable. Based on our recycling experimental results it can stated that,
- Different surfactants have unique properties which affect their deinking performance
- The tested sugar-based surfactant produced the highest ink removal efficiency and yield
- Sugar-based surfactant had comparable results to commercially-used surfactants
- Protein based surfactants had similar yields; however did not have the same ink removal efficiency
- The addition point of surfactants in the deinking process plays an important role in the overall result of deinking process: The sugar-based surfactant performed similar than the synthetic and commercially used surfactant in the pulper. However, the protein-based surfactant also showed poor performance when added to the flotation cell
Conclusions:
We demonstrated that sugar-based surfactants can replace petroleum-based surfactants currently used in industrial operations for paper recycling. Furthermore, our work in Phase I can be summarized as follows,
- The detergency phenomena of surfactants can be investigated by measuring contact angles of water on a model ink after exposing the model ink system to different surfactants.
- The ability of the surfactants to produce foam has been positively correlated to the flotation efficiency.
- The efficiency of a flotation cell (with respect to ink removal and process yield) is very sensitive to the surfactant chemistry utilized.
- The tested natural surfactants based on sugar components have high efficiency relative to synthetic (petroleum-based) surfactants in flotation deinking.
Based on our preliminary results we have a solid basis to believe that positive impacts can be achieved in making progress toward sustainability. The use of natural surfactants not only brings a positive environmental impact but also improves the performance and yield in recycling operation. The waste streams from deinking operations, which involve large volumes of a slurry containing residual ink, fiber losses, fines, mineral particles and, more importantly, deinking surfactant, will be transformed in that the surfactant to be disposed (landfilled) will be biodegradable. No health concerns will be tied with the handling and use of these wasted streams. Furthermore, we learned that in several mills in the US and developing countries the waste streams from recycling operations are used to produce structural bricks for construction (as oppose to regular land filling). The presence in these materials of natural surfactants as opposed to toxic, petroleum-based surfactants will be of great benefit and will provide further incentives for a more widespread utilization of these wasted materials.
Our measure of success was set in terms of the performance of the proposed surfactants in deinking operations, which is convincingly demonstrated in our Phase I results. Our project impact can be broadly applicable and transferable to various industry sectors in the US and developing world. However, due to the particular nature of our project, which involves industry operations instead of direct connection with people or communities, we realized the existence of limitations in terms of implementation in the actual industrial setting. To this end we visited a number industries and educational centers in Latin America where excellent possibilities for technology implementation have been identified and discussed.
Proposed Phase II Objectives and Strategies:
Limitation of the findings for the phase I research are (1) that only lab scale flotation deinking trials were performed and (2) methods to determine the underlying mechanisms that were governing performance were developed but there was not enough conclusive data to predict the efficiency of a surfactant based on structure. Phase II activities will address the above issues as well as the economic, social and environmental impact.
Therefore, the objectives for phase II are the following:
- Understand how the structure of the surfactants impact the underlying mechanisms of flotation deinking in order to propose new surfactant structures based on sugars that will perform even better.
- Optimize the application of the sugar-based surfactants at the lab-scale, determining the effects of surfactant concentration, waste paper type, surfactant point of addition, temperature, consistency, and residence time on the removal efficiency of ink and the usable fiber yield of the process.
- Demonstrate on a pilot plant scale the feasibility of sugar-based surfactants in flotation deinking relative to synthetic surfactants.
- Demonstrate in a commercial operation, the feasibility of sugar-based surfactants in flotation deinking relative to synthetic surfactants (see our Final Report for activities with industries in developing countries).
- Develop a definitive economic evaluation of the traditional paper recycling process with respect to the proposed sugar-based surfactants.
- Develop an understanding of the environmental and social impact of the paper recycling process with respect to the proposed sugar-based surfactants.
Journal Articles:
No journal articles submitted with this report: View all 2 publications for this projectSupplemental Keywords:
Water, watersheds, recycling, sustainable development, chemical exposure, health risk, toxic chemicals, bioavailability, organics, effluent, discharge, green chemistry, pollution prevention, alternatives, clean technologies, renewable, waste reduction, waste minimization, environmentally conscious manufacturing; environmental chemistry, engineering, analytical, surveys, nation, paper industry, recycling industry,, RFA, Scientific Discipline, INTERNATIONAL COOPERATION, TREATMENT/CONTROL, Sustainable Industry/Business, Environmental Chemistry, Sustainable Environment, Technology, Technology for Sustainable Environment, Chemicals Management, Environmental Engineering, renewable feedstocks, ink removal, clean technologies, alternative surfactants, biomass, recycling, surfactant recycle/reuse system, pollution prevention, green chemistryRelevant Websites:
http://www4.ncsu.edu/~ojrojas/ Exit
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.