A Review on Utilization Routes of the Leather Industry Biomass

Abstract

The use of biomass to produce bioenergy and biomaterials is considered a sustainable alternative to depleting fossil fuel resources. The world tanneries consume 8–9 MT of skin and hide every year producing 1.4 MT of solid waste. Most of the solid biomass generated from tanneries is disposed of as waste in the environment using either landfilling or thermal incineration. Disposal of this waste into the environment affects the ecosystem, causing bad odor (air pollution) and has an antagonistic impact on the environment. Due to this, European Union legislation bans the landfilling of biomass. This study aims to comprehensively review the possible valorization routes of leather processing industry biomass into high-value biomaterials. Leather biomass (trimmings, shaving, splitting, and buffing dust) mainly contain 30%–35% collagen protein, which is produced by acid or alkali hydrolysis. The biopolymers obtained from leather industry biomass can be utilized in the production of several high-value materials. In addition, leather processing industry biomass also contains fat, which can be converted into a bio-surfactant, and other useful biomaterials. Keratin protein can also be extracted from the hair waste of hides and skins. The increased demand for biomaterials makes the using of leather industry biomass very attractive. From this study, it can be concluded that the conversions of leather processing industry waste to valuable biomaterial can protect the environment, generate additional income for leather industries, and pave way for sustainable and renewable biomaterials production.

Functional Carbon from Nature: Biomass‐Derived Carbon Materials and the Recent Progress of Their Applications

“…That is, a slight change in it will lead to a huge change in sensing resistance. When CRT is exposed in air, oxygen can be absorbed on the CRT surface via the reaction of O 2(ads) + e − → O − 2 (6) resulting in the formation of a depletion layer on the surface of CRT. When CRT is exposed to NH 3 , two reactions will occur:…”

“…However, using biomass waste as a carbon precursor can convert this otherwise valueless waste into highvalue functional carbon materials. [6,7] In addition to protecting the environment and reducing costs, using biomass as a carbon source has many other advantages. Due to its high carbon content and diverse molecular structures, biomass can be made into carbon materials with different structures, allowing these materials to be applied in versatile applications.…”

“…However, using biomass waste as a carbon precursor can convert this otherwise valueless waste into high‐value functional carbon materials. [ 6 , 7 ]…”

Depollution of Polymeric Leather Waste by Applying the Most Current Methods of Chromium Extraction

“…This industry uses animal skins and hides as raw material [ 2 ], coming especially from the meat industry [ 5 ], to obtain a variety of products, such as belts, clothes, shoes, and bags [ 6 ]. Annually, the leather industry consumes approximately 8–9 million tons of raw skin and hide [ 7 ].…”

Development of Flexible Composite Sheet with Chrome Shavings Using Polyvinyl Alcohol as a Cross-Linker

“…One metric ton of raw hide generates about 200 kg of finished leather, 200-250 kg of tanned solid waste, and 200-350 kg of nontanned waste, and 100 kg is lost as wastewater [2,3]. Solid waste from tannery comprises of 2-5% hair, 5-7% skin trimmings, 35-40% buffing dust, CS, chrome split, wet blue scraps, and 56-60% fleshing [4,5]. These buffing dust, CS, and wet blue scraps contain a high quantity of chromium, whereas CS dust possesses 2.5-5% of chromium [6].…”