Factors Affecting Synthetic Dye Adsorption; Desorption Studies: A Review of Results from the Last Five Years (2017–2021)

Abstract

The primary, most obvious parameter indicating water quality is the color of the water. Not only can it be aesthetically disturbing, but it can also be an indicator of contamination. Clean, high-quality water is a valuable, essential asset. Of the available technologies for removing dyes, adsorption is the most used method due to its ease of use, cost-effectiveness, and high efficiency. The adsorption process is influenced by several parameters, which are the basis of all laboratories researching the optimum conditions. The main objective of this review is to provide up-to-date information on the most studied influencing factors. The effects of initial dye concentration, pH, adsorbent dosage, particle size and temperature are illustrated through examples from the last five years (2017–2021) of research. Moreover, general trends are drawn based on these findings. The removal time ranged from 5 min to 36 h (E = 100% was achieved within 5–60 min). In addition, nearly 80% efficiency can be achieved with just 0.05 g of adsorbent. It is important to reduce adsorbent particle size (with Φ decrease E = 8–99%). Among the dyes analyzed in this paper, Methylene Blue, Congo Red, Malachite Green, Crystal Violet were the most frequently studied. Our conclusions are based on previously published literature.

A Comprehensive Insight into Fungal Enzymes: Structure, Classification, and Their Role in Mankind’s Challenges

“…These dyes imply many serious impacts in the aquatic environment, including increasing water turbidity and inhibiting the growth of some organisms like algae. In addition, most of these dyes are carcinogenic with high hepatocellular and renal toxicity upon long-term exposure [186]. There are two major mechanisms for decolorization of dyes using fungi, which are biosorption and biodegradation.…”

Novel Fe3O4‐Modified Biochar Derived from Citrus Bergamia Peel: A Green Synthesis Approach for Adsorptive Removal of Methylene Blue

“…For lower adsorbate concentration the ratio of vacant binding sites to dye molecules is higher allowing MB to interact with Fe 3 O 4 CBC instantaneously resulting in an elevation in removal percentage. For higher concentrations of adsorbate, as the abundance of vacant sites is limited, that leads to a reduction in percentage removal of MB [41] …”

“…For higher concentrations of adsorbate, as the abundance of vacant sites is limited, that leads to a reduction in percentage removal of MB. [41]…”

Synthesis of Activated Carbon from Trachycarpus fortunei Seeds for the Removal of Cationic and Anionic Dyes

“…An adsorbent with smaller particles has a large surface area, thus it has a higher adsorption capacity compared to an adsorbent with a larger particle size, which may cause a decrease in the adsorption capacity of the larger particles. Too small particle size may float on surface and not adsorb the dyes well [ 58 ].…”