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The use of volunteers is one of the approaches to capacity building, preparedness and the response of the health system in disasters. Appropriate management of volunteers during disasters and emergencies is essential. This study aimed to explain the challenges of volunteer management in the Pandemic COVID-19 in Iran.

Qualitative research was conducted using the content analysis based on the Graneheim method. The participants' selection was done based on purposeful sampling and theoretical sampling until data saturation. Direct field observation and 26 interviews were applied to collect data.

Four categories and 15 sub-categories emerged to describe the challenges of volunteer management during the COVID-19 crisis including policymaking barriers (including legal barriers, insurance and support coverage and risk governance), managerial barriers (including planning, coordinating and organizing, training and awareness, command and leadership and information management and documentation), socio-cultural barriers (personal safety attitude and culture, attitudes and expectations of the community and perspectives on volunteers) and executive-operational barriers (monitoring and evaluation, cost and needs assessment).

It is essential to increase managers', officials' and volunteers' perceptions of COVID19 risk through education and information. Preparing a database for volunteers' information, including non-governmental organization and governmental organization volunteers, planning for needs assessment, establishing a mechanism for recruiting volunteers and using their capacities and appropriate organizing, tracking and monitoring of volunteers can be among effective strategies.

A series of sulfate-based Gemini anionic surfactants were synthesized via etherification, ring opening and sulfation reactions using epichlorohydrin, fatty alcohol, ethylene glycol and chlorosulfonic acid as the main raw materials. Orthogonal experiments for 1,8-bisalkoxymethylene-3,6-dioxin-1,8-octane disulfate were performed on the sulfation reaction to determine the optimal reaction conditions.

A series of sulfate-based Gemini anionic surfactants were synthesized via etherification, ring opening and sulfation reactions using epichlorohydrin, fatty alcohol, ethylene glycol and chlorosulfonic acid as the main raw materials. Orthogonal experiments for 1,8-bisalkoxymethylene-3,6-dioxin-1,8-octane disulfate were performed on the sulfation reaction to determine the optimal reaction conditions. The structures of the intermediate and final products were characterized by FT-IR (Fourier transform infrared spectroscopy analysis), ¹H-NMR (proton nuclear magnetic resonance spectroscopy) methods. The thermal performance of surfactants was analyzed using thermogravimetric analysis (TGA). The thermogravimetric results showed that the sulfate-based Gemini surfactants had good heat resistance (the thermal decomposition temperature of which was in the range of 140∼170?). The Krafft point, surface tension, foaming, Hydrophile–Lipophile Balance Number (HLB), emulsifying, wetting, and lime-soap dispersing performance were measured by visual observation, hanging drop method, aqueous surfactant solution method and Borghetti–Bergman method, respectively. The results have shown that all the sulfate-based Gemini surfactants had good water solubility and lime-soap dispersing ability. When spacer group was -(CH2)2-, with the increase of the carbon chain length from C12 to C14, the micellar concentration critical micelle concentration and surface tension (CMC) gradually increased from 8.25 × 10^–4 mol/L to 8.75 × 10^–4 mol/L and 27.5 mN/m to 30.9 mN/m, respectively. Also, the sulfate-based Gemini surfactants with the different length of the spacer group had a different effect on their performance on foaming properties and foam properties, HLB and emulsifying ability and wetting ability.

In view of the important role of the spacer group and the general use of anionic surfactants in oil fields, this article considers the preparation of a series of sulfate-based Gemini surfactants by changing the spacer group and the chain length of the hydrophobic group and evaluating their surface activity, and finally its Kraffi, on the foam properties, HLB value, emulsifying performance, lime soap dispersing ability etc.

Sulfate-based Gemini surfactants have broad application prospects in the fields of oil and gas exploitation, environmental protection, chemistry and daily chemical industry and so on.