Valorization of Agri-Food Wastes as Sustainable Eco-Materials for Wastewater Treatment: Current State and New Perspectives

Abstract

The paper addresses environmental protection by valorizing an important agri-food waste category, namely fruit and vegetables with focusing on the main characteristics regarding consumption, waste quantities, and ways for valorizing these materials. Thus, vast research was undertaken in order to emphasize the main commodities and their potential application as adsorbents for organic and inorganic pollutants. The main methods or treatment techniques applied for the valorization of eco-materials as adsorbents were presented and the principal efficiency results were indicated. The advantages and disadvantages of using these eco-materials as adsorbents in wastewater treatment were revealed and future recommendations were established. According to the international statistics, the most purchased and consumed five commodities were studied regarding waste generations as potential conversion into eco-materials with an adsorbent role for water pollutants. Thus, the performances for adsorbents based on fruit wastes (such as citrus, banana, apples, grapes, mango) and vegetable wastes (such as potatoes, tomatoes, cabbage, carrots, cauliflower, and/or broccoli) were studied and highlighted in this research.

Sustainable Use of Apple Pomace (AP) in Different Industrial Sectors

“…Fruits, including apples, that deviate from the imposed standards, for example in terms of size and visual elements (colour intensity, discolouration, skin elasticity, defects: bruises, rots) are often discarded by producers, consumers and retailers [ 25 ]. It is estimated that approximately 3.7 trillion apples end up in landfills each year [ 26 ]. Furthermore, such a waste of food and improper AP waste management causes huge losses of water, land, fertilizer, energy, labour and capital, which are economically unprofitable [ 24 , 27 ].…”

The influence of separately and combined bentonite and kaolinite as binders for pelletization of NaA zeolite from coal fly ash

“…Agro-industrial wastes and by-products are eco-friendly adsorbents because they are locally available and low-cost sources for water and wastewater treatment applications [1,2]. Many materials can be used as low-cost adsorbents, such as rice straw and husks rice straw [3], raw/activated sawdust [4,5], diatomaceous earth [6], and sugarcane bagasse [7][8][9][10].…”

“…1 31 3. 24.2 13.8 5.40 3.57 0.758 0.694 0.447 0.071 0.031 0.026 0.022 0.021 <0.001 19.61 : loss on ignition.…”

Surface Modified Activated Carbons: Sustainable Bio-Based Materials for Environmental Remediation

“…Utilization of agricultural wastes or biomasses for solving environmental problems could be considered as an effective and green strategy in environmental protection as they are inexpensive, renewable, and locally available in large quantities [2][3][4]. In the literature, agricultural wastes have been proposed as an economic and eco-friendly precursor for ACs [5][6][7][8][9]. The agricultural wastes are rich in lignocelluloses, mainly composed of polysaccharides such as cellulose (35-50%), hemicellulose (20-35%), and an aromatic polymer, lignin (10-25%) [10].…”