Application of Cold Region Regenerable Biomass in Phosphorus Adsorption in Reclaimed Water

Abstract

In order to enhance the using efficiency of the adsorbent and decrease production costs, reclaimed saturation Lanthanum modified pine needles (LH pine needles) have been studied as a possible solution. Pine needles gathered from the woods of Northeast China area were used as raw material for generating LH pine needles by alkali-isopropanol treatment and chemical precipitation. To explore the utilization of LH pine needles as a recycling adsorbent in wastewater treatment plants (WWTPs) and laboratory water distribution. Results show that removal effective of phosphorus (P) by LH pine needles in low concentration reclaimed water of WWTPs was 41% and up to more than 92% in its adding standard. In the wide pH range, LH pine has an effective adsorption capacity for phosphorus; pH can also interfere with the adsorption capacity of LH pine as there is a negative correlation between them. The adsorption of phosphorus by LH pine needles is divided into three stages with a pH ranging from 3~11. Ligand exchange reaction, electrostatic reaction and Lewis acid reaction are PO 4 3− adsorption mechanism. The analysis of the recycling efficiency of LH pine needles proved that LH pine needles have good regeneration performance. After being eluted by NaOH regeneration agent for more than 10 times, the adsorption efficiency of phosphorus can still be stable at over 90% in seven cycles.the emission of phosphine gas [9]. Due to different P concentrations in solutions, the P adsorption capacities of substrates vary greatly [10]. Our previous research of the removal of P was only at laboratory scale of water distribution, while research and mechanism analysis in actual WWTPs were yet executed [11]. Adsorption mechanism is a necessary part of adsorbent which plays an important role in pollutant removal of reclaimed water. During the last decade, studies of adsorbent on phosphorus have been conducted varied, including in sodium bentonite/clay (BC) [12], Modified cottonwood fiber, etc. [13]. The effectiveness for P removal with different absorbing materials have also been compared [11,14,15]. However, most adsorbent studied to date are used to treat P of sewage in few cycles, and very few studies investigated the use of adsorbent in recycling, let alone use a recycling biosorbent.Different kinds of natural and synthetic adsorbents have been used to remove pollutants from wastewater [16,17]. Biomass adsorbent has been widely used in wastewater treatment due to its purification effect on lower phosphorus wastewater. 2.12 million hectares of camphor pine and red pine in Changbai Mountain in the northeast of China produces 14.84 million tons of pine needles annually. However, these pine needles are abandoned normally. Biomass adsorbent can improve the adsorption efficiency by changing the adsorption properties: increasing the pore channel and specific surface area of adsorbent, or changing the cationic species attached to the surface of adsorbent. Hence, pine needles with pore structure are supposed to be good carbon-based biomass adsorbents....