Desalination of Agricultural Wastewater by Solar Adsorption System: A Numerical Study

Abstract

There are still areas around the world suffer from severe shortage of freshwater supplies. Desalination technologies are not widely used due to their high energy usage, cost, and environmental damaging effects. In this study, a mathematical model of single-bed adsorption desalination system using silica gel-water as working pair is developed and validated via earlier experiments. A very good match between the model predictions and the experimental results is recorded. The objective is to reveal the factors affecting the productivity of fresh water and cooling effect in the solar adsorption system. The proposed model is setup for solving within the commercially-available software (Engineering Equation Solver). It is implemented to solve the mass and heat balance equations for the adsorbent bed, condenser, and evaporator components. At a typical temperature of 89 °C and flow rate of 30 m3/sec for the hot water entering the bed, the following results are reported: (a) the specific daily water production of 1.89 m3 /ton of silica gel/ day, (b) coefficient of performance of 0.32, and (c) specific cooling power of 40.82 W/kg of silica gel. The concentration of salt (X) in the product (desalinated water) has been set with value of 0.5 gm/kg to be suitable for drinking and irrigation. The salt concentration in the evaporator is estimated to be 4.611 gm/kg during the overall adsorption process. The results from this study should be of wide interest for the field of solar water desalination and air-conditioning.

Experimental investigation on the performance of a pyramid solar still for varying water depth, contaminated water temperature, and addition of circular fins

“…Raising the temperature at which water is introduced increases evaporation by increasing the water's thermal energy. The increased energy promotes a faster conversion of liquid to vapour, leading to greater evaporation and freshwater production (AlRubaiea et al 2021).…”

Adsorption of Methylene Blue on Fix Bed Column Using Adsorbent from Tea Waste

“…The most common and widely used adsorption isotherm models in adsorption are the Langmuir and Freundlich isotherm models [38][39][40] shown in Eqns. ( 5) and (6).…”

“…Generally, the liquid waste produced includes dyestuffs. Dyes are organic or inorganic compounds that give color to textiles, food, beverages, medicines, and cosmetics [6]. There are two types of dyes; natural and synthetic dyes, but synthetic dyes are more widely used [7,8].…”

Optimization of Methylene Blue Dye Adsorption in Fixed Bed Column Packed with Tea Waste via Response Surface Methodology

“…The chemical industry is proliferating along with the increase in the world's population. Industries that use synthetic dyes in manufacturing their products are also increasing, including the textile, paper, medicine, food, cosmetics, printing, and rubber industries [1]. Synthetic dyes contain compounds with complex aromatic molecular structures, making them challenging to decompose when discharged naturally into the environment [2].…”