Mohammad Abu Haija

Review of technologies for biotreatment of refinery wastewaters: progress, challenges and future opportunities

Rapid urbanization and industrial development has led to increased discharge of wastewater from process plants such as oil and gas refineries in recent years. Refinery wastewater is a complex mixture of various organic and inorganic compounds. Due to their toxicity and increased generation volume, environmentally accepted disposal of oily wastewater is a current challenge to the petroleum industry worldwide. Besides, stringent global standards have necessitated new and existing facilities to achieve higher levels in wastewater treatment to recover more water for re-use. Compared to different physical and chemical methods employed in effluent treatment, biological processes are considered to be environment-friendly, benign, profitable and cost effective. In this review, the source, characteristics and toxicity impact of petroleum refinery wastewater (PRW) is introduced. A comprehensive summary on the recent developments of different biotreatment techniques adopted for PRW refinement, with reference to inorganics and heavy metals have been discussed. Based on observations, it is inferred that no individual process can be considered as a panacea, since each method is outlined by several advantages and limitations. This work aims to help future researchers and practitioners to have a good understanding of the present progress and future perspectives in the field.

Removal of iron from industrial lean methyldiethanolamine (MDEA) solvent by adsorption on sepiolite

ABSTRACT Sepiolite clay was used as an adsorbent for the removal of iron ions from industrial methyldiethanolamine (MDEA) solvent. The raw sepiolite clay was modified by different chemical and thermal treatments, and was characterized by FTIR, XRD, SEM-EDX, and BET-specific surface area analysis. Treating sepiolite with nitric acid significantly improved the adsorption capacity of iron ions from lean MDEA. The experimental equilibrium data were represented by Henry, Freundlich, and Langmuir isotherm models. The thermodynamic parameters indicated that the adsorption of iron ions on sepiolite was spontaneous and endothermic process. The kinetic studies showed that the adsorption followed pseudo-second order model.

Enhanced removal of methyl violet 6B cationic dye from aqueous solutions using calcium alginate hydrogel grafted with poly (styrene-co-maleic anhydride)

Calcium alginate hydrogel was grafted with poly (styrene-co-maleic anhydride) synthetic polymer (PSMA) and used as an adsorbent for the effective removal of methyl violet 6B cationic dye from aqueous solutions. The characteristics of native and grafted alginate hydrogels were investigated using FTIR, Zetasizer and TGA/DSC. The carboxyl groups’ content and the swelling properties were determined as well. Batch adsorption experiments were conducted as a function of initial dye concentration, adsorbent dosage, solution ionic strength, solution pH, time of contact and temperature. Results revealed that grafting of PSMA onto alginate improved the removal percentage of the dye up to 30%. The highest adsorption capacity of the dye was obtained at a temperature of 40xa0°C, a pH range of 5–11 and at lower solution ionic strengths. The kinetics of adsorption followed the pseudo-second-order model and the equilibrium data could be better described by the Langmuir isotherm. The maximum adsorption capacity was found to be 109.9xa0mg/g suggesting the promising potential of our low-cost adsorbent for the removal of cationic dyes from aqueous solutions. A desorption study was carried out where the adsorbent showed high desorption characteristics and it could be reused at least for five consecutive cycles.

Graphene as an Efficient and Reusable Adsorbent Compared to Activated Carbons for the Removal of Phenol from Aqueous Solutions

The adsorption capacity of graphene for removing phenol from aqueous solutions was evaluated and compared to those obtained for three different commercial activated carbons. In this study, graphene, W-35 activated carbon, RB2H2 activated carbon, and Nuchar granular activated carbon were investigated. Various techniques such as X-ray diffraction, BET surface analysis, and scanning electron microscopy were used to characterize the adsorbents. The adsorption of phenol onto graphene was investigated under different experimental conditions including temperature, solution pH, adsorbent dosage, and initial concentration of phenol. For comparison, adsorption experiments of phenol onto the activated carbons were also conducted. The adsorption of phenol onto graphene and activated carbons could be described by the pseudo-second-order kinetic model and the Langmuir equilibrium isotherm. The maximum adsorption capacities predicted by the Langmuir isotherm for graphene, W-35, RB2H2, and Nuchar granular activated carbons were found to be 233, 200, 91, and 167xa0mg/g, respectively. The thermodynamic study demonstrated that the adsorption of phenol onto graphene and activated carbons is a spontaneous and exothermic process. Regeneration of graphene was found to be possible using sodium hydroxide or methanol as eluents over five adsorption-desorption cycles.

Effect of different solvents and clay loading on Polyacrylamide hydrogel to remove Iron from Lean Methyldiethanol solvent

The polyacrylamide (PAAM) hydrogel consisting of acrylamide and 2(methacryloyloxy) ethyl aceto acetate as monomer, N, N/-methylenebisacrylamide as crosslinker and ammonium peroxodisulfate as initiator was prepared using different solvents. Methanol, ethanol, dimethylsulfoxide and deionized water was used as solvent to prepare the hydrogel. Its usefulness as adsorbent for the removal of iron as contaminants from industrial lean methyl diethanol amine solvents (MDEA, 50 weight % used by GASCO Company, Abu Dhabi for natural gas sweetening) was tested. Finally, PAAM hydrogel in water with nitric acid treated sepiolite having different loading were prepared to increase the mechanical strength of the composite hydrogel. SEM and FTIR analysis of the PAAM clay composite hydrogel explained the morphology and adsorption process. PAAM composite hydrogel with 12.5 % clay loading was found to be best using batch adsorption studies for the removal of iron (45.15% having uptake capacity 6.397 μg/g using 1.0 g hydrogel) from industrial lean MDEA solvent.