Recent use of selected phytochemistry to mitigate environmental challenges facing leather tanning industry: a review

Leather tanning technology impacts negatively on the environment as a result of chemicals in the tannery effluents that increases the concentrations of chemical oxygen demand, Biological oxygen demand, total dissolved solids, total Kjeldahl Nitrogen and formation of Cr(VI) among others in the environment. This has led to the profiling of the industry by legislative bodies as a major source of pollution and hence urgent cleaner and eco-friendly innovative technologies are required that will mitigate the environmental pollution. Many studies have recommended green chemistry tanning protocols and systems involving plants since are non-carcinogenic, non-toxic, biodegradable, agro-renewable, sustainable and economical. Numerous studies have evaluated the potential of phytochemistry in leather tanning processes. However, these studies only focused on individual processes or individual plant phytochemicals. Hence this review compiles the selected plants, their phytochemical screening results, their applications in tanning process and their potential for leather tanning. The review has shown enormous capacity of plants and their phytochemicals that can replace synthetic inorganic materials in leather processing and guarantee quality. Plants have a greater applicability in this industry since they have multiple beneficial actions during processing and the final processed leather. Some plants can be used at all tanning processes due to wide variety of important phytochemicals and the final leather is more superior quality to the conventionally processed leather. Other studies have alluded to the possibility of some plant products that have the potential in the industry but yet to be utilized. Further studies have been recommended.