Graduation Year

2021

Document Type

Thesis

Degree

M.S.C.H.

Degree Name

MS in Chemical Engineering (M.S.C.H.)

Degree Granting Department

Chemical Engineering

Major Professor

Norma Alcantar, Ph.D.

Committee Member

George Philippdis, Ph.D.

Committee Member

Sylvia Thomas, Ph.D.

Keywords

NE, GE, FTIR, COMSOL, MATLAB

Abstract

As water is one of the primary sources of life, it is essential in an endless number of systems and processes to be utilized efficiently in nature and in practical applications. One of these applications includes farming, which depletes a lot of water as the water irrigation systems cover large soil areas. While water is a critical factor in growing crops, a question here stands, can the irrigation process be transformed? This is the overarching goal of my work since it is centered on studying if cactus mucilage, a natural substance, is capable of improving water absorption processes on crops during the irrigation process.

This research examines the change in the amount of absorbed water in soil and whether or not such amount is affected by cactus mucilage being mixed within the soil. This process will be done by simulating and predicting the water absorption process with and without cactus mucilage using the COMSOL, which is a Multiphysics analysis and solving software suite, using sugar as a model system to represent cactus mucilage.

Moreover, in surface gravity irrigation, there are three phases: the advanced phase, the storage phase, and the recession phase, which together are studied using various models to understand water flow phenomena. The differential equations which describe the water transfer in soil systems could be solved using numerical methods that simulate the moisture profile evolution and the infiltrated depth during gravity irrigation. Simulations of water redistribution patterns after irrigation due to the gravitational field. Results are revealed using Darcy’s law and the Richards equation, which are used to predict the behavior of the soil-water system when adding mucilage. Moreover, it is representing the attitude of variables on the system. The study showed that Darcy’s variable is independent of changing the composition of the flow. On the other hand, the Richards equation is subject to change when adding mucilage. It was found that the Richards equation was the best model to describe the characteristics of the soil-water system using cactus mucilage. This work also found that the optimal water holding capacity was accurately modeled by the Richards equation as analyzed by COMSOL for each mucilage extraction added to the soil system.

In closing, this work also includes experiments where the optimal amount of cactus mucilage that led to water content in soil systems was determined by using different percentage amounts of cactus mucilage 0.1, 0.125, 0.15, and 0.20. Other significant findings also include the optimal ratio of the two fractions of cactus mucilage known as the Gelling Extract (GE) and the Non-Gelling Extract (NE) in the system in the system were used as 4NE:1GE and 1GE:4NE. It was also found that increasing the GE amount forms a thin, protective layer on the top of the soil, which will be of interest in future study investigations. The result of the experiment was used to determine the parameters needed to update the simulation model to fit the experimental data. Finally, this work provides valuable information to transform how water absorption can be optimized in soil systems to improve water uptake and improve crop production rates.

This study will help to model the new system and use it for the next stage to study how it will help to reduce irrigation water needed for plants and reduce the amount of water needed in each irrigation run. The success of this new model will help increase the production of agricultural crops to match the significant demand for water to grow crops worldwide.

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