Textile industry being one of the most flourishing industries keeps growing and developing every year, and the consequences are not very pleasant. Even though its contribution towards economy of a country is indisputable, there are many pros and cons associated with it that should not be brushed aside, one of them being textile dye waste which is also growing at alarming rate. Many techniques have been designed to deal with this environmental crisis including adsorption and photodegradation of dye waste by various substances, both natural and synthetic. TiO2 and clay both have gained immense popularity in this area. Over the last decade, many successful attempts have been made to design TiO2-clay-based composites to combine and make the most of their individual capabilities to degrade textile dye waste. While clay is an effective adsorbent, inexpensive, innocuous, and a great ion exchanger, TiO2 provides supplementary active sites and free radicals and speeds up the degradation rate of dyes. This review summarizes various features of TiO2-clay-based composites including their surface characteristics, their role as dye adsorbents and photocatalysts, challenges in their implementation, and modifications to overcome these challenges made over the last decade.

The photocatalytic degradation of dyes (alizarin red S, amaranth, congo red, and rhodamine B) present in wastewater was performed with UV lamp. The catalysts employed for this investigation were ZnO, TiO2, and SnO2. The kinetic studies of dyes degradation followed first order reaction. ZnO was found to be most efficient photo-catalyst for degrading these dyes. The optimal result for alizarin red S was k = 0.2118 min−1, t1/2 = 3.27 min, and R2 = 0.7998, for amaranth was k = 0.146 min−1, t1/2 = 4.74 min, and R2 = 0.8348, for congo red was k = 0.2452 min−1, t1/2 = 2.8 min, and R2 = 0.8382, and for rhodamine B was k = 0.1915 min−1, t1/2 = 3.6 min, and R2 = 0.76.

The usage of dyes has been tremendously augmented due to industrialization and human’s intrinsic fascination with colors. Owing to their excessive usage in industries like textiles, food, cosmetics, paints, printing etc., it is indisputably a contributing factor in aquatic pollution. Dyes effluents have emerged as a burgeoning challenge. Owing to issues such as toxicity, mutagenicity, and disturbed photosynthesis associated with dye contamination, it is crucial to look for an explication to deal with this challenge. Polypyrrole-based biocomposites have been reported as good adsorbents for textile wastewater treatment. In the last decade, numerous studies have stated the effective removal of dyes via Polypyrrole-based biocomposites. This review concentrates on the implication of different Polypyrrole-based biocomposites for decontamination of dyes and synthesis methods, characteristics, and mechanism of dyes degradation by these biocomposites from wastewater.

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