Highly Efficient Adsorption of P-Xylene from Aqueous Solutions by Hierarchical Nanoporous Biochar Derived from Crab Shell

The global consumption of p-xylene(PX)for the production of polymers has raised serious concerns about its impact on the environment.As various reports have shown the risks that PX could pose to human health,research into cost-effective remedial methods to remove PX from the environment has gained attraction.In this work,a hierarchical porous crab shell biochar(KCS)was synthesized,characterized,and evaluated for its efficiency to remove PX from aqueous solution.The characterizations of KCS,including the porous structure,surface functional group,phase structure,and surface morphology,were discussed by N_(2) adsorption-desorption,FTIR,XRD,and SEM.Batch adsorption experiments showed that the maximum adsorption capacity of PX on KCS was 393 mg/g within 5 min,larger than most biological/biomass materials,mainly due to the higher specific surface area of 2046 m^(2)/g,and abundant lipophilic functional groups.Subsequent adsorption kinetics study indicated a pseudo-second-order model which implied that the adsorption of PX was due to chemisorption.Thermodynamic parameters showed that the values ofΔH°andΔG°were both negative,indicating that the PX adsorption process on KCS was spontaneous and exothermic.The performance of KCS in delivering a cost-effective,fast,and efficient solution for the removal of PX from aqueous solution would greatly benefit current environmental remediation efforts.

Facile Preparation of a Porous Biochar Derived from Waste Crab Shell with High Removal Performance for Diesel

In this study,a porous biochar material derived from waste crab shell was prepared by one-step hydrothermal carbonization and acetic acid activation method at 180°C,which was characterized by SEM,BET,XRD and FTIR.The results show that the as-prepared crab shell biochar(CSB)exhibits a fluffy irregular layered structure with abundant pores and oxygen-containing functional groups,which can facilitate the adsorption of diesel using CSB.In addition,batch adsorption experiments had been performed,effects of initial diesel concentration,adsorption time,adsorbent dosage and pH on the diesel adsorption using CSB were analyzed,which could be observed that CSB has high removal efficiency for diesel,and the maximum removal rate is up to 80.1%.The adsorption isotherms and kinetic studies were also investigated to determine the adsorption mechanism of diesel using CSB,the results show that the Langmuir model and the pseudo-second-order model are more suitable for describing the adsorption of diesel using CSB,indicating that the adsorption of diesel oil by CSB is monolayer chemical adsorption.This study will provide a theoretical basis for the high-value utilization of waste crab shell,which has a great potential in the treatment of oil spill.

Preparation of Porous Materials Derived from Waste Mussel Shell with High Removal Performance for Tableware Oil

In this work,carbonized mussel shell powder(CMSP)was modified by alkyl polyglucosides(APG)and rhamnolipid(RL)to render porous biomass a lipophilic surface,which was innovatively utilized as an environmentally friendly tableware cleaning material.The modified method was two-step hydrotherm-assisted synthesis.A contact angle meter was used to determine the surface hydrophobic property of modified samples(MTAR).The pore and the surface structure of CMSP and MTAR were characterized by BET,SEM,XRD,FTIR and XPS.The effect of removing oil was tested by gravimetric method.The results showed that the surface of MTAR was more porous and fluffier than CMSP,and the specific surface area is increased by 16.76 times.The results showed that when calcining CMSP at 1000℃,the oil removal rate of the synthesized MTAR is the best,and the decontamination rate can reach 87.05%.This research aims to develop a green and environmentally-friendly tableware cleaning material,solve environmental problems,and make full use of waste,which is very conducive to environmental protection.

Study on Net Hauler Safety Device for Fishing Vessels

[Objective] To design a safety device set for fishing vessel net hauler, in order to reduce the severe potential safety hazards in offshore operation. [Method] In view of the operation and structure of net hauler on the fishing trawler, this paper investigated the existing safety protection devices and designed a new set of purely mechanical structure without changing the original structures of the vessel significantly. [Result] Using the easily-adjustable functions of the main shaft of CNC lathe, and simulating the operation performance of different hauling line speeds and testing the safety device, the results showed that the new device could protect the crew from safety accidents caused by net hauler. [Conclusion] The result provides references for the design and application of mechanical protection devices for net haulers on other fishing trawlers.

Numerical Study on Water Depth Effects on Hydrodynamic Forces Acting on Berthing Ships

Due to the restrictions of ports, maneuverability of berthing ships will be affected significantly by water depth. In the present study, numerical simulation of the berthing maneuver of a ship with prescribed translational motion is performed by solving the Reynolds-averaged Navier-Stokes(RANS) equations based on overset grid,and the effects of the quaywall and freesurface are taken into consideration. To validate the present numerical method, comparison is performed between our results and the other results or measurements. It is found that the agreement is significantly better than that resulting from previous CFD-based approach. Subsequently, the effects of various water depths are investigated to evaluate their influences on hydrodynamic forces. The present results can provide helpful guidance on safe maneuvering for vessels' berthing and fender system design in quays.