**6.1. Industrial byproducts**

Low-cost materials from different industries have been used for the treatment of wastewater. Many industries, especially food industries, dispose large quantities of waste and byproducts. The cost for disposal is sometimes challenging. Using these zero-cost industrial wastes as effective biosorbents for treating wastewater effluents can solve the dual problem (waste disposal and effluent treatment) [57]. Waste byproducts produced from different industries, that is, steel, aluminum, paper, fertilizer, food, mining, and pharmaceuticals, can be used as biosorbents. It is estimated that the use of biosorbents from industrial waste will grow at an annual rate of 5% [58]. **Table 2** summarizes the type and source of the biosorbent, type of biosorbate targeted, and maximum biosorption capacity/biosorption efficiency of various industrial biosorbents.


a Indicates the dry weight of the biosorbent, \* Indicates batch biosorption experiments at laboratory scale.

**Table 2.** Use of industrial byproducts for biosorption of metal ions.
