Valorization of Pine Cones (Pinus nigras) for Industrial Wastewater Treatment and Crystal Violet Removal: A Sustainable Approach Based on Bio-Coagulants and a Bio-Adsorbent

Abstract

Pine cones are a widely available and abundant natural resource in Algeria, and they are rich in active molecules. This study investigated the valorization of Pine cones as a natural and abundant bio-coagulant in raw form (powder) and extract form. The active components of the Pine cones were extracted using two solvents, distilled water (DW) and NaCl, to obtain coagulants (proteins, polyphenols, and carbohydrates) for the treatment and improvement of industrial water quality parameters (discharge from a processing plant and tomato production) and an adsorbent (residue extract, RE). The recovered bio-coagulant was used to remove turbidity, chemical oxygen demand (COD), and zeta potential. The formed adsorbent was used to remove crystal violet (CV). Coagulation-flocculation experiments were carried out in a jar test to evaluate the performance of the coagulant in powder and extract form. The use of pine cone powder (PCP), extract using NaCl (PC-NaCl), and extract using DW (PC-DW) resulted in turbidity reductions of 96%, 94%, and 98%, respectively. For the residue recovered after extraction, a CV removal percentage of 99.9% was achieved at the optimal conditions of pH 10, CV concentration of 20 mg/L, adsorbent dose of 20 mg/L, and contact time of 120 min, as determined using the Box–Behnken design (BBD). Furthermore, all the effects were significant in the process of the CV phase adsorption on the bio-adsorbent. The model designed for optimal design fit the experimental data well, with a coefficient of determination, R2, of 0.965 and an Adj-R2 of 0.926. The p-value of this model was 0.000, which indicated that the model was very significant. This confirmed the effectiveness of the bio-adsorbent in removing dyes from water.

Combined Effects of Banana Peels and Pith as Dual Natural Plant-Based Coagulants for Turbidity Removal

“…On the other hand, the effectiveness started to drop rapidly when the pH is increased to neutral and moderate alkaline pH except for BPPS coagulant. This is in agreement with the result obtained by Baatache et al, [44]. Depending on the solution pH, the decrease of turbidity removal could be due to different mechanisms either by charge neutralization, polymerization bridging effect, or electrostatic patch.…”

“…This finding is consistent that the repulsive forces tend to stabilize the suspension and prevent particle agglomeration [37]. In addition, coagulating agents such as proteins and polysaccharide in banana peels and pith facilitate the coagulation of colloids through the adsorption and bridging mechanisms [44].…”

Removal of Chromium (VI) from Water Using Orange peel as the Biosorbent: Experimental, Modeling, and Kinetic Studies on Adsorption Isotherms and Chemical Structure

“…Figure 2 reports the graphical calculation of pH pzc ; at pH = 2.63, the surface charge is zero. For pH values higher than pH pzc , the biosorbent surface charge is negative [58,59].…”